I SDMS Document 106290
POHATCONG VALLEY GROUNDWATER CONTAMINATION SITE
STATEMENT OF WORK FOR EPA REGION 6 RESPONSE ACTION CONTRACT 4 JUNE 1,1999
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EXECUTIVE SUMMARY i
0.0 INTRODUCTION 1
O.I SCOPE OF WORK OBJECTIVES 2
0.2 WORK PLAN FORMAT 2
0.3 REFERENCES 3
0.4 BACKGROUND 3 0.4.1 Site Location And Description 3 0.4.2 Site History 4 0.43 Sealed Private WeUs 7 0.4.4 Site Geology 7 0.4.4.1 Stratigraphy and Lithology 7 0.4.4.2 Structure 9 0.4.4.3 Geologic Features and Implications for Groundwater Movement 10 0.4.5 Site Conceptual Hydrogeologic Model 10 0.4.5.1 General Hydrologic Conditions 11 0.4.5.2 Thickness And Hydraulic Properties Of The Glacial Deposits 12 ^^ 0.4.5.3 Recharge, Movement, And Discharge Of Groundwater In The Glacial ^B Deposits 13 0.4.5.4 Bedrock Beneath The Valley And Hydraulic Properties 14 0.4.5.5 Water Levels In The Bedrock Aquifer 14 0.4.5.6 Recharge, Movement, And Discharge Of Groundwater From the Bedrock AquiferlS 0.4.5.7 Groundwater • Surface Water Interchange 15 0.4.6 Site Contaminants 15 0.4.6.1 Groundwater 15 0.4.6.2 Soil 16 0.4.6.3 Historical Uses 16 0.4.6.4 Fate And Transport 16
0.5 PRELIMINARY HUMAN RISK ASSESSMENT 18 0.5.1 Potential Source Areas 19 0.5.2 Migration Pathways 19 0.53 Routes of Exposure, Potential Receptors, and Preliminary Assessment of Risk 20 0.5.4 Public Health and Environmental Assessment Data Needs 23
0.6 PROBLEM SUMMARY23 0.6.1 Site Investigation Plan 24 0.6.1.1 Methodologies For Identifying PSAs 24 ^^
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0.6.1.2 Recommended Actions For PSAs 25 0.6.1.2.1 PSAs Requiring Field Investigations 25 0.6.1.2.2 Sites Requiring Site Inspections 26 0.6.1.2.3 Sites Requiring No Further Action 26 0.6.2 Hierarchical List of PSA Sites 26 0.6.3 Preliminary Identification of Potential Remedial Technologies 27 0.6.3.1 General Response Actions 27 0.6.3.2 Potential Remedial Technologies 29 0.6.4 ARARs and Guidance To Be Considered 29 0.6.4.1 Definition of ARARs and TBCs 29 0.6.4.2 Types of ARARs and TBCs 30 0.6.4.3 Consideration of ARARs During the RI/FS 31 0.6.5 Preliminary Remedial Action Objectives 32 0.6.6 DQO D€termination32 0.6.7 Field Investigation Scope of Work 35
TASK I PROJECT PLANNING AND SUPPORT 40 1.1 Project Management 40 1.2 Access Agreements 40 1.3 Project Organization, Schedule and Costs 41 1.3.1 Project Organization 41 1.3.2 Initial Site Inspection4l 1.3.3 Scoping Meeting 41 1.3.4 Work Plan Submittal 41 * TASK 2- COMMUNITY RELA TIONS 42 2.1 Project ImplemerBtation42 2.2 Public Meeting/Public Availability Session Support 42 23 Fact Sheet Preparation 43 2.4 Develop an Internet Site 43 2.5 Prepare Public Notices 44 2.6 Prepare and Update a Site Mailing List 44
TASK 3 FIELD INVESTIGATIONS 44 3.1 Collection and Evaluation of Existing Data 45 3.2 Fracture Trace Analysis 46 33 Cultural Resources Investigation 47 3.4 Subcontract Procurement 48 3.5 Delineation of Wetlands 49 3.6 Survey of Endangered Species Habitat 50 3.7 Mobilization 50 3.8 Soil Gas Investigations 51 3.9 SampUng Existing Wells 52 3.10 Surface Geophysical Investigations 54 3.11 Drilling, Subsurface Sampling, and Well Installation 55 3.12 Downhole Geophysical Investigations 66
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3.13 Surface Water and Sediment Sampling 69 ^JP 3.14 Surveying 70 3.15 Quarterly Monitoring and Sampling 71 3.16 Landscape Restoration 72 3.17 Demobilization 73 3.18 Phase I Report 73 3.19 Phase U RI Work Plans 74 3.20 Phase II Mobilization 74 3.21 Surface and Borehole Geophysical Investigations 74 3.22 Drilling and Environmental Sampling 74 3.23 Hydraulic Testing 75 3.24 Dye Tracer Tests 76 3.25 Ecological Sampling 78 3.26 Surveying 78 3.27 Landscape Restoration 79 3.28 Phase II Demobilization 79
TASK 4 SAMPLE ANALYSIS 79 4.1 Sample Management and Tracking 80 4.2 Sample Analyses 81 43 Independent Laboratory Analysis 82 4.4 Delivery of Analytical Services Laboratory Procurement 83 4.5 Sample VaUdation 83 4.6 Quality Assurance Officer 85
TASK 6 DATA EVALUATION 85 6.1 Database and GIS Development 85 6.2 Evaluation of Analytical Data 91 6.3 Evaluation of Other Data 92 6.4 Graphical Presentation of Data 93 6.5 Phase II RI Groundwater Flow and Chemical Transport Modeling 94 Groundwater Flow Model 94 Fate and Transport Modeling 96
TASK? RISK ASSESSMENT 97 7.1 Phase I - Risk-Based Screening 97 7.1.1 Initial Screening - Soil Gas Survey 97 7.1.2 Risk-Based Screening - Human Health Direct Contact 98 7.1.3. Risk-Based Screening - Human Health Impact to Groundwater 99 7.1.4 Risk-Based Screening - Ecological Criteria 99 7.1.5 Reporting Results - Risk-Based Screening 100 7.2 Phase II - Baseline Risk Assessments 100 7.2.1 Human Health Risk Assessment 101 7.2.1.1 Site Visit and Meeting 101 7.2.1.2 Data Collection and Evaluation 101 7.2.1.3 Quantitative Evaluation 104 ^W
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7.2.1.4 Current Land-Use Conditions 105 7.2.1.5 Future Land-Use Conditions 106 7.2.1.6 Toxicity Assessment and Documentation 108 7.2.1.7 Risk Characterization 109 7.2.1.8 Qualitative Evaluation of Chemicals Without Toxicity Criteria 110 7.2.1.9 Discussion of Uncertainties 110 7.2.2 Ecological Risk Assessment 110
TASK 8 TREATABIUTYSTUDY/PILOT TESTING 119 8.1 Disposal of RI/FS Generated Wastes 119
TASK 9 REMEDIAL INVESTIGATION REPORT 120 9.1 Draft Remedial Investigation Report 120 9.2 Final Remedial Investigation Report 122 3 Meetings 123
TASK 10 REMEDIAL ALTERNATIVES SCREENING 123
TASK II REMEDIAL ALTERNATIVES EVALUATION 124 11.1 Remedial Technologies Evaluation 124 11.2 FS Groundwater Flow and Transport Modeling 128
TASK12 FEASIBILITY STUDY REPORT AND RI/FS REPORT 129 • 12.1 Development Of Remedial Action Objectives, General Response Actions, and Volumes of Contaminated Media 130 12.2 Identification Of Applicable Technologies And Assembly Of Alternatives- 131 12.3 Draft Feasibility Study Report 132 12.4 Final FeasibiUty Study Report 134 12.4.1 Meetings 134
TASK 13 POST RI/FS SUPPORT 134 13.1 Public Notices 134 13.2 Proposed Plan 134 133 Proposed Plan Public Meeting 135 13.4 Responsiveness Summary 135
TASK 16 WORK ASSIGNMENT CLOSEOUT 136 16.1 Technical FUe Closeout 136 16.2 Accounting File Closeout 136 16.3 WACR Preparation 136
REFERENCES 136
I 300038 ft APPENDICES APPENDIX A - FACILrrY PROFILES
APPENDIX B - 1 JUNE 1998 HIERARCHICAL LIST OF SITES
LlSTOFnGURES**
Figure 1-1 Site Location Map
Figure 1-2 Site Topography Map
Figure 4-1 Drilling Cost Comparison
Figure 4-2 Sampling Location Map: Washington Township Municipal Garage
Figure 4-3 Sampling Location Map: Warren Controls, Broadway Restoration, . Sinclair Station, Warren County Vocational School, Luckey's Autobody, Fielbach Welding
Figure 4-4 Sampling Location Map: Modem Valet, L&L Dry Cleaners, Szathmary Building Supply, Washington Auto Top and Trip, % Maxon Chevrolet/Ashman Autobody, Blews Brothers Autobody, Washington Borough Garage, Warren County Auto Parts, Mobil Gas Station, Washington Theatre, Rossi Pontiac, Washington Transmission. Rossi Body Shop
Figure 4-5 Sampling Location Map: Tung-Sol Tubing, BASF Corporation, Washington Auto Parts, Somerset Tire Service, Smith Motors, Petty's Tire and Auto
Figure 4-6 Sampling Location Map: American National Can Company, Standard Oil Tank Farm, Szalbrit Residence, Vikon Tile Corporation (Former), Mike's Autobody, Mueller Roofing Metric Motors, '70" Garage, Washington Auto Salvage
Figure 4-7 Sampling Location Map: Five Carp Company, Dave's Friendly Service Station, Stew's Autobody, Gulf Service Station, Guy's Auto Service, Banner Pontiac (Former) New Jersey Bell, Bill and Vem's Service, Opdykes Sales and Service
Figure 4-8 Sampling Location Map: Washington Porcelain Company (Former), AID Models Hedges and Brothers
Figure 4-9 Sampling Location Map; Brockway Plastics
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Figure 4-10 Sampling Location Map: Highpoint Sanitary Landfill
Figure 4-11 Sampling Location Map: Agway Energy Products, Pohatcong Service Station, Red's Autobody
Figure 4-12 Sampling Location Map: Kober's Auto Parts
Figure 4-13 Sampling Location Map: Victualic
Figure 5-1 Project Organization
•Broadway Lawn Mower, Broadway Motors, and JCP&L are not represented on these figures.
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LIST OF PLATES PLATE NO.
1 Site Base Map 2 Site Base Map - Washington Twp. 3 Site Base Map - Franklin Twp. 4 1984 Warren County Health Dept Study of TCE in Domestic Wells and the Current Water Main Extensions 5 Geologic Map and Cross Section 6 Monitoring Well Locations 7 Monitoring Well Locations - Washington Twp. 8 Monitoring Well Locations - Franklin Twp. 9 Domestic Well Locations 10 Domestic Well Locations - Washington Twp. 11 • Domestic Well Locations - Franklin Twp. 12 Sites Identified Within the PVGCS m 13 Potential Source Areas Within the PVGCS 14 Potential Source Areas - Washington Twp. 15 Potential Source Areas - Franklin Twp. 16 Wetland Map 17 Proposed RI Well Sampling Locations 18 Field Testing Locations 19 Project Scheduling
I 300041 LIST OF TABLES
2-1 Soil and Groundwater Contaminants Detected in Environmental Media 2-2 Range of Biodegradation Rates and Transport Characteristics of Chlorinated Organic Solvents Cited in Scientific Literature
2-3 Contaminant Screening Levels and Method Detection Limits for Volatile Organics in Surface and Groundwater 0 2-4 Contaminant Screening Levels for Semivolatile Organics in Surface and Groundwater 2-5 Contaminant Screening Levels for Inorganics in Surface and Groundwater 2-6 Contaminant Screening Levels for Volatile Organics in Soil and Sediments 2-7 Contaminant Screening Levels for Semivolatile Organics in Soil and Sediments 2-8 Contaminant Screening Levels for Inorganics in Soil aral Sediment 3-1 Sites Within PVGCS Identified by the 1997 File Review and 0 the 1989 Industrial Survey 3-2 Summary of PSAs with Contaminated Environmental Media f 3-3 Summary of PSAs in which Solvents Were Reportedly Used
3-4 Summary of Autonxjtivc and Other Industries Which May _ Use TCE and/or PCE 0 3-5 Summary of Sites Receiving Wastes for Disposal 3-6 Summary of Sites Requiring Site Inspections Q 3-7 Summary of No Further Action S ites 3-8 Initial Screening of Remedial Technologies - Groundwater 0 3-9 Initial Screening of Remedial Technologies - Soil 3-10 Potential Chemical-Specific ARARs 3-11 Potential Location-Specific ARARs 0 3-12 Potential Action-Specific ARARs 4-1 Domestic Wells Located in Washington Township 0 4-2 Doniestic Wells Located in Franklin Township
4-3 Industrial Wells Located Throughout Study area Q 4-4 Monitoring Wells Located in Washington Township f 300042 I
4-5 Monitoring Wells Located in Franklin Township * 4-6 Monitoring Wells Located in Washington Borough
4-7 Existing Wells to be Sampled in Task 3.09
4-8 Potential Source Area Sample Summary Table
4-9 Sample Analysis Summary Table
4-10 Soil and Sediment Sample Geotechnical, Geochemical. and Engineering Analyses 4-11 Groundwater Sample Geotechnical, Geochemical, and Engineering Analyses
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EXECUTIVE SUMMARY I t I I I f I I t I I 1 I I
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I 300044 EXECUTIVE SUMMARY #
The Pohatcong Valley Groundwater Contamination Site, located in Warren County, New Jersey, encompasses approximately 5,600 acres of rural, industrial, residential and municipal land. Volatile organic compound (VOC) groundwater contamination has been documented at the site since 1978. VOC concentrations in groundwater are reported to range from non- detectable levels to approximately 770 micrograms per liter (parts per billion). Semivolatile organic compounds (SVOC) and metals have also been detected above risk-based screening levels at the site. In 1986, the NIDEP extended public water lines to affected residences and established a well restriction area to mitigate risks associated with ingesting contaminated groundwater.
In 1989, ICF Kaiser Engineers, Inc. (ICF Kaiser) under the US Environmental Protection Agency (USEPA) ARCS n Contract prepared a Draft Work Plan, Field Operations Plan, and other project-related documents for the remedial investigation of approximately 40 of 121 potential source areas identified during a file search and an industrial survey. This work was discontinued in 1990. In August 1997, USEPA reactivated the project to finalize the planning dqcuments. In December 1997, ICF Kaiser submitted the revised Draft RI/FS Work Plan and Draft Final Site Investigation Plan for: the remedial investigation of 58 potential source areas (PSAs); the characterization of the horizontal and vertical extent and chemical composition of the groundwater contamination; the preparation of a human and ecological risk assessment; and the performance of a Feasibility Study. This document is the Final Work Plan and incorporates EPA comments on the December 1997 draft planning documents. The objectives of the RI/FS ^^r are:
To characterize the vertical and horizontal extent and chemical composition of groundwater contamination at the site; To identify potential contaminant source areas; To assess human health and ecological risks posed by the contamination; and To develop and evaluate remedial alternatives to mitigate the risks posed by contaminated media.
The Remedial Investigation is comprised of two phases. Phase I will include a multi-media ^ investigation to identify likely sources of groundwater contamination and to characterize the M nature and extent of the groundwater contamination in the Valley. Phase 11 will focus on ™ investigating the sources identified in Phase L ^
During Phase I of the RI, up to approximately 1,395 groundwater, surface water, sediment, ^ and Quality Assurance/Quality Control (QA/QC) samples will be analyzed in EPA's Contract r Laboratory Program (CLP) for VOC, SVOCs, and metals. Approximately 15 samples will be analyzed for waste characterization by an independent laboratory and approximately 40 samples ^y
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Pohatcong Valley Groundwater Contamination Slta May 1999 Statement of Work WA# 037-RI-CO-02 4 will be analyzed for drinking water parameters by EPA's Environmental Services Division (ESD) laboratory. During Phase II of the RI: approximately 314 environmental media samples may be analyzed in EPA's CLP; approximately 5 samples may be analyzed for disposal characterization
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Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Worl< WAtt 037-RI-CO-02 by an independent laboratory; and 10 samples may be analyzed for engineering parameters to support the Feasibility Study. This equates to approximately 190,000 chemical analytical data points. To efficiently organize, manage and present the field and analytical data, a Geographical Information System (GIS) database will be developed. After data collection activities in Phase I and Phase n are completed, groundwater Modeling Software will be used to assist in predicting the fate and transport of contaminated groundwater and to analyze remedial alternatives. To reduce surveying costs associated with identifying sampling points, a global positioning system will be employed during Phase I and Phase n to map the sampling locations. The Phase n objectives and scope will be determined based on the Phase I results.
If the Phase I and Phase II data are sufficient to characterize the contamination at the site, human and ecological risk assessments will be performed to identify and characterize the toxicity and potential adverse effects associated with the contamination. The results of the risk assessments and the Phase I and II RIs will be incorporated into the Remedial Investigation Report (RIR). The findings and recommendations in the RIR will provide a basis for determining whether or not a Feasibility Study will be performed.
' Remedial alternatives to mitigate the risks posed to human and ecological populations by contaminated media will be identified and assessed in the Feasibility Study. Approximately 40 remedial technologies including several innovative technologies will be screened and then assembled into media specific remedial alternatives for approximately 6 separate source areas and the regional groundwater contamination problem. The FS will commence as soon as adequate data are available to determine the need for an FS which may be initiated during t preparation of the RIR. FS data needs may be identified during the data evaluation task requiring additional field or treatability studies. These additional data quality activities could be performed while the draft RIR is being prepared and the initial steps of the FS are conducted.
4 16 300047 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA^ 037-RI-C0-02 f 0.0 INTRODUCTION The Pohatcong Valley Groundwater Contamination Site (PVGCS) encompasses approximately 5,600 acres of rural, industrial, and municipal land within Warren County New I Jersey. The Pohatcong Valley Study Area extends approximately 4.5 miles from Washington Borough to the community of Broadway. Volatile organic compound (VOC) contamination has been documented in the groundwater at the site since 1978. The results of well sampling events I conducted in 1984 and 1985 by the Warren County Health Department and the New Jersey Department of Environmental Protection (NJDEP) indicated that trichloroethylene and tetrachloroethylene were detected in concentrations ranging from less than detectable levels to t 440 and 510 micrograms per liter (parts per billion), respectively. In 1985, the NJDEP established a well restriction area in the Pohatcong Valley, and in 1986-1987, a public water I supply was provided to affected residences. Several activities have been performed by the NJDEP and the U.S. Environmental Protection t Agency (EPA) to identify the sources of the groundwater contamination within Pohatcong Valley. These activities include extensive records and file reviews by ICF Kaiser Engineers (ICF Kaiser) and Alliance Technologies Corporation on behalf of the EPA Region n, field I inspections of commercial and industrial facilities by ICF Kaiser and NJDEP, aerial photograph reviews by EPA, and limited sampling activities by NJDEP.
On 8 August 1997, ICF Kaiser was tasked to conduct a Remedial Investigation/Feasibility Study for the PVGCS. The first steps in the planning process were to attend scoping meetings I and a site visit, to conduct a records search of available files, and to prepare a Draft Site 1 Investigation Plan (SIP). The Draft SIP presented EPA's approach to investigating potential source areas (PSAs) identified in the records search and to characterizing the groundwater contamination in terms of I its vertical and horizontal distribution and chemical composition. The Draft SIP included: a summary of the file review findings; a listing of the tentatively identified PSAs identified during the file review; a preliminary estimate of the number, type, and location of samples to be I collected; and problems, issues and limitations associated with the proposed investigatory methodologies. The Draft SIP also included several updated site maps of the PVGCS which depicted geologic and environmental features within the study area, presented available I groundwater quality data, and identified the locations of domestic and monitoring wells within and immediately outside of the PVGCS. The Draft SIP was revised based on comments provided by EPA, NJDEP, and U.S. Geologic Survey, and resubmitted to EPA for review as the I Draft Final SIP.
I The next step of the planning process was to prepare a Draft Work Plan which presented a description of the technical approach to the RI, the activities to be performed in conducting the FS, and an estimated schedule and budget for the RI/FS. The Draft Work Plan was submitted to t EPA along with the Draft/Final SIP. The Draft Work Plan and Draft/Final SIP were reviewed by
I ' 300048 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-C0-02 EPA, NJDEP, U.S. Geologic Survey, U.S. Fish and Wildlife Service, and the National Oceanic and Atmospheric Administration. Comments provided by these agencies have been incorporated into this Statement of Work. The contents of the SIP have been included in this incorporated into this Statement of Work while the 1987 Industrial Survey and 1997 file review are incorporated into as Appendix A. 0.1 SCOPE OF WORK OBJECTIVES
The objectives of the Pohatcong Valley Groundwater Contamination Remedial Investigation/Feasibility Study are to:
To characterize the site-wide vertical and horizontal extent and chemical composition of groundwater contamination at the site; To identify potential contaminant source areas; To conduct investigations at potential contaminant source areas to assess potential impacts to groundwater quality, including soil, sediment, surface water, soil gas and groundwater sampling; To evaluate receptors, and assessment of risks, posed by the contamination, and; To develop and evaluate remedial alternatives which mitigate the risks to human and ecok
The Remedial Investigation is comprised of two phases. Phase I of the RI field investigation will include a multi-media investigation to identify likely sources of groundwater contamination and to characterize the appropriate nature the vertical and horizontal extent of the groundwater contamination in the Valley.
The Phase I RI will include: collection, management, and analysis of environmental samples; reduction and evaluation of data; initial screening of PSAs using criteria presented in Section 4.6.1; characterization of the Valley's hydrogeology; and assessment of wetlands and sensitive ecological habitats. The screening of PSAs and the identification of sites to be investigated during the Phase II RI will be based on analytical data fix)m soil gas investigations, analytical results of samples collected from monitoring and residentialwells ; and the soil and groundwater samples collected during drilling activities at selected PSAs. A letter report will be prepared to present the results of the Phase I investigation, identify those PSAs which are considered likely, potential, and not likely sources of contamination, and identify data gaps needed to be filled in Phase n to complete the risk assessment and FS.
The second phase of the RI (Phase n RI) will continue the multi-media investigation by focusing on investigating areas which were identified in the Phase I RI as likely contributors to the Pohatcong Valley site contamination problem. The Phase n objectives and scope will be determined based on the Phase I results. For the purpose of project scoping and cost estimating, it is assumed that approximately 6 of the original 58 PSAs will be identified as potential sources areas in the Phase I report. The Phase II RI will also include tasks that allow for the collection of
300049 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-C0-O2 data which will supplement the data collected during the Phase I RI. If data collected during Phases I and II are sufficient to characterize the vertical and horizontal extent of contamination at a the source areas, a human and ecological risk assessment and feasibility study will be performed. n During Phase I of the RI, EPA estimates that approximately 1,395 groundwater, surface water, sediment, and Quality Assurance/Quality Control (QA/QC) samples will be analyzed in 9 EPA's Contract Laboratory Program (CLP) for VOC, SVOCs, and metals. Approximately 15 samples will be analyzed for waste characterization by an independent laboratory, and approximately 40 samples will be analyzed for drinking water analysis by EPA's Region 2 0 Environmental Services Division (ESD) laboratory. During Phase n of the RI, approximately 314 environmental media samples will be analyzed by EPA's CLP, approximately 5 samples will be analyzed for disposal characterization by an independent laboratory, and 10 samples analyzed for engineering parameters to support the Feasibility Study. This equates to approximately 190,000 chemical analytical data points. To efficiently organize, manage and present these data, a Geographical Information System (GIS) database will be developed. After data collection 0 activities in Phase I and Phase 11 are completed, groundwater Modeling Software will be used assist jn predicting the fate and transport of contaminated groundwater and to analyze remedial alternatives. To reduce surveying costs associated with identifying sampling points, a global Q positioning system will be employed during Phase I and Phase n to map the sampling locations.
For the purpose of cost estimating, the Contractor should assume that approximately 20 of the original 58 PSAs will require Phase I investigation following the soil gas surveys, and that 6 will be identified as potential sources areas in Phase II.
If the Phase I and Phase II data are adequate, human and ecological risk assessments will be performed to identify and characterize the toxicity and potential adverse effects associated with contamination present at the site. The risk assessments will provide a basis for determining whether remedial action is necessary at the site and justification for performing a Feasibility Study and subsequent remedial action if required. The results of the risk assessments and the phase I and II RIs will be incorporated into the Remedial Investigation Report (RIR).
Remedial alternatives to mitigate the risks posed to human and ecological populations by contaminated media will be identified and assessed in the Feasibility Study. Approximately 40 remedial technologies including several innovative technologies will be screened and then assembled into media specific remedial alternatives for approximately 6 separate source areas Q and the regional groundwater contamination problem. The FS will commence as soon as adequate data are available and may be initiated during preparation of the RIR. FS data needs may be identified during the data evaluation task requiringadditiona l field or treatability studies. 0 These additional data quality activities could be performed while the draft RIR is being prepared and the initial steps of the FS conducted.
P 0.2 WORK PLAN FORMAT
0 3 300050 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA» 037-RI-CO-02
An approved Region 2 RI/FS Work Plan was edited and modified to be used as the Statement of Work for this RI/FS work assignment under the Response Action Contract (RAC) format. Sections of the work plan were rearranged into the work breakdown structure established for the RAC program. Where possible the Tables, Figures, Appendices and References remained unchanged. Appendix A (facility profiles) contains the results of the 1989 Industrial Survey and 1997 file review conducted by ICF Kaiser.
0.3 REFERENCES
This Statement of Work and RI/FS Work Plan were prepared in accordance with:
Guidance for Conducting Remedial Investigations and Feasibility Studies under CERCLA (EPAy54O/G-89/0O4, October 1988); Superfund Amendments and Reauthorization Act of 1986; ii Data Quality Objectives Guidance (OSWER Directive 9335.07-7B, March 1987); Data Quality Objectives for Superfund, Interim Final Guidance (EPA-R-93-071, 8 September, 1993); Guidance for the Data Quality Objectives Process (EPA QA/G-Y, September, 1994); Exposure Assessment Guidance (OSWER Directive 9285.5-0, April 1988); Interim Final Risk Assessment Guidance for Superfund (RAGS)~Human Health Evaluation'^ Framework for Ecological Risk Assessment (USEPA, 1992a); Community Relations Guidance (OSWER Directive 9230.0-3A, June 1988); and Community Relations in Superfund: A Handbook (January 1992, EPA/540/G-88/002).
0.4 BACKGROUND
0.4.1 Site Lootiomi And Descrsptioim
Pohatcong Valley is a northeast-southwest trending valley which extends from northeast of the Borough of Washington (Washington Borough) to the Delaware River in Warren County, New Jersey (Figure 1-1). The PVGCS study area, as presented in Plate 1 (and, in greater detail, on Plates 2 and 3), extends southwesterly from approximately 2.5 miles north-northeast of 0 Washington Borough (Route 31) to the town of Broadway. Greater details of the area are shown for Washington and Franklin Townships in Plates 2 and 3, respectively. The northern and southern study-area boundaries are primarily delineated by the bases of the mountains (Oxford
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Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA« 037-RI-Ca<}2 and Pohatcong) bordering the valley. The topography of Pohatcong Valley near Washington and Franklin Townships is presented in Figure 1-2. The total area encompasses approximately 8.75 square miles. Land use in the Pohatcong Valley includes rural farms within portions of Washington and Franklin Townships and relatively densely-populated residential areas in Washington Borough (5,600 acres). The extension of the Erie Lackawanna Railroad lies along the base of the Pohatcong Mountains. There are a large number of commercial and retail businesses within Washington Borough focused principally along major roads. Other commercial facilities are located sporadically with Franklin and Washington Townships. Most industrial facilities (past and present) within Washington Borough are located in the fringes of the Borough, particularly along the Erie Lackawanna Railroad.
Potable water in Pohatcong Valley is supplied almost exclusively from groundwater contained within rock and unconsolidated-glacial overburden aquifers beneath the valley. The population within the study area is supplied entirely by these aquifers. Therefore, these aquifers are considered sole-source aquifers.
0.4.2 Site History
In the late 1970s, two public supply wells in Washington Borough owned by the American Water Company were found to be contaminated with volatile organics. The two contaminated p wells were Well #3 located at Vannatta Street Station and Well #4 located on Dale Avenue. The wells are between 200 and 400 feet deep, respectively, and draw from the fractured limestone of the Kittatinny Formation. Trichloroethylene (TCE) and tetrachloroethylene (PCE) were detected in the Vannatta Street well at 1.7 parts per billion (ppb) and 8.3 ppb, respectively, on July 5, 1978. A water sample collected from the same well in October 1978 contained 2.8 ppb of TCE and 299.6 ppb of PCE. On February 15, 1979, an analysis of the Dale Avenue well water identified 44.0 ppb of TCE (PCE was not detected). The following month's water sample of the Dale Avenue well contained 160.0 ppb of TCE and 4.0 ppb of PCE. PCE and TCE are the two primary chemical compounds consistentiy identified in samples obtained from the Vannatta Street and Dale Avenue wells, respectively.
The highest recorded concentration of PCE identified in the Vannatta Street well is 561.38 ppb. The highest recorded concentration of TCE identified in the Dale Avenue well is 231.0 ppb (NJDEP file document, September 21,1981).
On September 5,1981, the Vannatta Street well was placed back into service with a newly- installed carbon-ti^atment system. Although the Dale Avenue well does not supply water to the public, it is reported that the well is reserved for emergency-demand situations. Reportedly, public water is also supplied to residents in the study area by the Changewater Road well, located approximately 1.5 miles east-southeast of Washington. p In 1984 the Warren County Health Department conducted a study of potable wells within the
I 300052 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-C0-02 # area. Out of 93 samples collected and analyzed for TCE, 44 contained concentrations of TCE ranging from 1 to 440 ppb (see Plate 4).
In 1985, the NJDEP collected well water samples from 24 locations in Washington and Franklin Townships. Total volatile organics detected ranged from non-detected to 519 ppb, with the highest concentration detected in a well located approximately 600 feet west northwest of the Percarpio Industrial Park Site along Brass Castle Road.
A May 7, 1985 NJDEP memorandum stated that contamination of the aquifer began prior to 1978 and was a continuing problem; because of the aqOifer contamination, NJDEP was recommending that a well restriction area be delineated in Washington and Franklin Townships. It was also recommendedtha t a potable water supply be provided to areas affected or likely to be affected in the future.
In 1985, NJDEP established a well restriction area (WRA) which encompassed the affected residences within the Pohatcong Valley area. The WRA essentially delineated a known contaminant plume within EPA's study area, but did not encompass other areas later identified as having groundwater contamination.
On July 25,1985 and July 29,1985 die NJDEP entered into contracts with Warren County " for the installation of approximately 225 service connections and the sealing of all wells within the WRA.
On December 13,1985, the NJDEP and the American Water Company entered into a contract for the installation of water mains within the WRA to replace the approximately 233 domestic wells and wells used by the Warren County Vocational Technical School and the Franklin Township Elementary School.
A July 8,1987 NJDEP memorandum stated that seven possible sources had been identified as potential contributors to the contamination of domestic, industrial, and public potable water wells within the NJDEP well restriction area. The memorandum also contained a summary of analytical results ftxjrawate r and soil sampling conducted by the NJDEP at the seven facilities.
On March 31,1989 the EPA placed the PVGCS on the National Priority List (NPL). The PVGCS encompasses approximately 5,600 acres within Franklin Township, Washington Township, and Washington Borough.
On October 11, 1988, ICF Kaiser, under EPA contract number 68-W8-0124, received a Work Assignment (WA) for the remedial investigation, risk assessment, and feasibility study of the PVGCS. Between May and June 1989, ICF Kaiser completed surveys of industrial properties within the Pohatcong Valley area to identify potential sources of the groundwater 5 300053 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAU 037-RI-CQ-O2 4 contamination. In August 1989, ICF Kaiser submitted a draft work plan and field operation plan to implement the statement of work (SOW) associated with the Pohatcong Valley WA.
On November 16,1989, the NJDEP completed the installation of water mains, service connections, and the sealing of wells. Approximately 193 residents and businesses were connected; however, 40 residents within the area did not agree to be connected to the public water supply system. Plate 4 depicts the public water-line extensions identified by the American Water Company.
On August 8,1997, ICF Kaiser received an amendment to the October 1988 SOW to proceed with the PVGCS RI/FS.
On September 29,1997, ICF Kaiser submitted the Draft SIP to EPA which presented CF Kaiser's proposed approach for investigating and identifying potential source areas (PSAs) within the Pohatcong Valley and characterizing the groundwater contamination in terms of its vertical and horizontal distribution and chemical composition.
Between August and December 1997, ICF Kaiser reviewed available NJDEP ECRA/ISRA and BUST files, EPA CERCLA-related files, and Warren County Healtii Department files to • update the PSA profiles. The information obtained during this file review benefitted the overall understanding of the area-wide contamination problem in the valley.
On December 23,1997, ICF Kaiser submitted the Draft Work Plan and Draft/Final SIP to EPA which presented plans for conducting a multi media field investigation of 58 PSAs, analysis of environmental samples, data management, data evaluation, data reporting, human and ecological risk assessments and a FS. In the Work Plan, ICF Kaiser described how several innovative sampling technologies including temporary well point sampling, vibratory drilling, and soil gas sampling will reduce costs and to expedite the field investigation.
In January 1998, ICF Kaiser submitted the draft FOP which described the field task organization, the responsibilities of the individuals involved in the field investigation, and provided the technical guidelines and procedures to be followed by the field personnel conducting the RI. The draft FOP also identified the sampling and analytical methods and objectives, health and safety requirements, and Quality Assurance/Quality Control (QA/QC) protocol for sample collection, handling, shipping, and analyses.
In June 1998, ICF Kaiser prepared a hierarchical list of sites which, based on the information 0 obtained during the 1989 Industrial Survey and 1997 File Review, contributed to the groundwater contamination at the Site.
In June 1998, ICF Kaiser prepared a fracture trace analysis report. The report included
6 300054 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA0 Q37-RI-CO-02 several digitized aerial photographs which depicted the fractures in bedrock identified by the project hydrogeologist, a summary of the methods used to identify the fracture traces on the aerial photographs, interferences encountered during the identification of the fractures traces on the aerial photographs (i.e., fencelines, deer paths, etc.), and an explanation of the importance of the fracture trace analysis to the RI.
In January 1999, ICF Kaiser was tasked by the U.S. Army Corps of Engineers, Baltimore Distiict under contract DACA31-95-D-0083 to prepare the Final Work Plan.0,4.3 Sealed Private Wells
There are approximately 321 domestic, agricultural, industrial, and monitoring wells within the immediate upper Pohatcong Valley area. Of the 321 wells, 82 private domestic wells within the WRA were sealed as part of NJDEP's public water line extensions in 1986-87.0.4.4 Site Geology
The Pohatcong Valley site is located in the Highlands physiographic province of New Jersey. This province occurs as a geographically thin belt of intensely folded and faulted sedimentary strata, igneous intrusive rocks, and metamorphic suites resultingi n a series of parallel ridges and intervening valleys. The topography of the region is controlled by the structure and weathering characteristics of the bedrock units. Valley floors are generally composed of limestone and other carbonate units; whereas, the ridges are generally composed of more competent igneous, metamorphic, or sandstone formations.
The Site vicinity is characterized by emergent thrust faults which cut through complex folds of sedimentary rocks (Paleozoic age) and older igneous and metamorphic rocks (see Plate 5). The southern boundary of the site is the northeast-southwest trending Pohatcong Mountain ridge which is composed of a metamorphic suite, including gneiss and amphibolite. The northern margin (Oxford Mountain) is a similarly ti:ending ridgecompose d of metamorphic rocks and igneous intrusions. The valley between these two ridges is bounded by thrust faults and is composed of a tightly folded and faulted syncline containing Cambrian and Ordovician (570-450 million years ago) quartzite and carbonate formations (Plate 5). Overlying the carbonate formations in the valley floor is glacial outwash and till of variable thickness, and recent alluvium deposited by the Pohatcong River. Some colluvium may have been deposited along the edges of the valley.
The regional strike of the formations located within the study area is northeast-southwest. Dip angles vary by location; however, most formations are near vertical throughout the area of study. Stratigraphic and structural elements within the study area are very complex. A cross section across the valley south of Broadway is included in Plate 5. This cross-section clearly illustrates the complex structural components, including folded strata, thrust faults and deformation along fault zones (e.g., mylonitization and cataclastism). Given the overall complexity of the study area, a "system-wide" approach to characterization is not appropriate. Therefore, the following paragraphs itemize the geologic elements within the study area and
300055 I
Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAff 037-RI-C0-02 discuss the relevanceo f each element to the development of a conceptual hydrogeologic model I for the study arei.0.4.4.1 Stratigraphy and Lithology Stratigraphy. Many different rock types of widely different ages are present within the study area. Successive deformation events have greatly complicated the distribution of the formations, I and in some places, deformation results in stratigraphic relationships that are difficult to decipher. Throu^out the study area, however, the basic stratigraphic relationships include (1) bordering mountain ridges composed of Proterozoic-age metamorphic and igneous (crystalline) I rocks and, (2) a valley floor underlain by early Paleozoic carbonate bedrock which has been tightly folded and displaced by thrust faulting. It is assumed here, based on general lithologic characteristics, that most of the groundwater within the study area vicinity occurs within the I carbonate bedrock and overlying glacial material that are contained within the Pohatcong Valley.
I The crystalline bedrock (igneous and metamorphic varieties) form the mountain ridges within the study area. This topographic position indicates that the crystalline rock is resistant to weathering and erosion. Typically, fractures in crystalline rocks are most abundant at the surface f and diminish with depth (representing "unloading" fractures). However, due to the fact that some fractures within the crystalline bedrock originated during extreme deformation events, I large-scale fractures (i.e., lineaments) may be present, and if so, they could offer significant conduits for groundwater flow. Localized fractures that carry large quantities of groundwater can often be identified using fracture trace analysis and similar techniques, and this potential will be evaluated. Groundwater flow rates within the crystalline bedrock ridges is probably much p lower than the overall groundwater flow rates within the valley floor.
I Sedimentary bedrock in the study area is primarily representedb y the older formations of the Lehigh Valley Sequence (Drake et al., 1994). Formations present in the study area include the I Hardyston Quartzite, the Leithsville Formation, the Allentown Dolomite, and the undifferentiated formations of the Beekmantown Group (Plate 5). The Martinsburg Formation is I absent in this area (A. Drake, personal communication, 1997). The Hardyston Quartzite (Lower Cambrian) is the basal Cambrian sandstone in the area. It is anarkosic and dolomitic sandstone that varies in thickness from a few feet near Mountain Lakes r to a maximum of 200 feet regionally. In the study area, this formation occurs mostly at depth with the exception of the southern arm of the syncline where it (x:curs near the surface (along the I trace of the Pohatcong Thrust fault).
The Leithsville Formation (Middle to Lower Cambrian) is a carbonate unit that varies greatly in composition over its 800 ft thickness. This formation underlies about half of Washington Borough, northeast along Shabbecong Creek, and northward along Route 31 (Plate 5). It is combined with the Hardyston Quartzite on the cross section. Drake (personal communication, 9 1997) indicates that this formation is one of the primary karst formations in the study area.
300056 Pohatcong Valley Gnsundwater Contamination Site May 1999 Statement of Work WA» 037-RI-C0-02 The Allentown Dolomite (Upper Cambrian to Lower Ordovician) is a shaly dolomite that varies in character from medium to coarse grained and is generally thickly bedded. Approximate thickness of this unit is 1,900 feet regionally. In the PVGCS, this unit subcrops beneath the majority of the valley floor, as shown in Plate 5.
As shown in the cross section, the formations younger than the Allentown Dolomite belong to the undifferentiated Beekmantown Group (Lower Ordovician). These units are thin to medium bedded shaly limestone units that are regionally extensive; total thickness of this group is more than 800 feet. According to Drake (personal conununication, 1997), this group is the other main karst unit in the area of study.
Glacial sediments overlie most of the Pohatcong Valley floor. These sediments include clay, silt, sand, and gravel, most of which are interpreted to be unsorted glacial till. The glacial deposits are Illinoisan or pre-Dlinoisan age. Recent alluvium along streams is also present.0.4.'^.2 Structure
Faults. Faulting occurs when the strength of the stressed rock formations is exceeded by the deformational force. In the study area, most of the thrust faulting has occurred within carbonate formations because these formations are less competent. However, fault "zones", or shear zones, exist across all lithologies and were created by mechanical deformation along the fault plane. Shear zones are characterized by lithologic transformations along the plane of movement due to the intense frictional forces at the point of contact between opposing fault blocks. Lithologic transformations include the development of mylonitic and cataclastic zones which are basically stretched, granulized, and recrystallized mineral grains within the rock matrices along the fault plane. Shear zones can be thick depending fault stress characteristics and the competence of lithologies exposed on each fault block.
As to groundwater movement, the shear zone sometimes reduces the overall matrix permeability within the formations bounding the fault and may serve as a hydraulic barrier to groundwater flow (i.e., across the fault) at depth. Along the fault trace, however, infiltration to the fault zone may actually be increased due to higher fracture permeability localized at the fault itself. Therefore, the faults may serve to focus infiltration and distribute recharge at depth. Future work with observed groundwater levels within the study area may help clarify hydraulic conditions related to faulting.
Folds. The fold identified in the valley carbonate formations was originally called the Alpha Antiform (Drake, 1967); this term implies that although the feature exhibits anticlinal form, the stratigraphic relationships are not known. More recent work in the valley has proposed that the fold is synclinal (Monteverde et al., 1994). Folded strata generally exhibit a concentration of fractures along the axis of the fold that can favor the development of fracture-contirolled conduits for groundwater flow. In anticlines, extension fractures are focused along the crest of the fold and in synclines compression fractures are concentrated in the ti-ougho f the fold. Because of the tight folding and associated faulting observed in the study area, it is likely that fractures in the •I
300057 I
Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037'RI-C0-02 4 Strata may be abundant and interconnected. Abundant and interconnected fractures lead to greater groundwater flow through the fracture network. In carbonate bedrock, greater flow I through fractures will lead to greater dissolution of bedrock matrix and better development of karst features. I Fractures. Rock fractures present in the study area are due to both deformation events and to unloading. Several different deformation events have been identified in the rock record at this I location and each event has a characteristic fracture pattern resulting from the particular compressional stress. Fractures resulting from unloading events (rock mass removed by erosion) are concentrated near the land surface. Work proposed herein for the site will help map I fracture sets and groundwater flow within the study area. I I I
* i i I I i I i
t 10 300058 I
Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-C0^2 0.4.4.3 Geologic Features and Implications for Groundwater Movement
#
P II 300059 1 ^ Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAff 037-RI-C0-02 0.4.4.3 Geologic Features and Implications for Groundwater Movement Karst. The soil survey for Warren County (1979) indicates that from a planning perspective, carbonate bedrock present near the ground surface results in a high probability of sinkhole development and therefore limits land use in these areas to farming. The development of large- scale karst features where carbonate formations are present is extremely important to the understanding of the groundwater flow system within the study area. More detailed mapping of large-scale dissolution features may lead to a greater understanding of the role karst plays in the overall groundwater system at the site. Well-developed karst aquifers can, in many cases, be adequately characterized with dye tracing techniques and the potential use of tracing methods is described in this document
Glacial Deposits. The exact hydraulic relationship between glacial outwash and the underlying carbonate bedrock is not known; however, given the apparent karst character of the carbonate bedrock and the downward flow direction in the till (see Section 5.0), it is anticipated that the two units are hydraulically connected. Glacial deposits within the valley store groundwater, which percolates downward and recharges the bedrock aquifer. In the lower valley, the glacial deposits receive flow from underlying karstic bedrock and discharge groundwater to the creeks. In fact, the topographic low point in Pohatcong Creek near Broadway (indicated as wetlands soils in the soil survey) may be a regional "upwelling" or discharge zone for deeper groundwater. Future work at the site will clarify the role of the glacial deposits in the p valley groundwater system. Recharge and Discharge. Recharge characteristics in fractured and karst bedrock typically include flashy and non-uniform responses to precipitation events. As noted above, the mantel of glacial deposits overlying the carbonate rocks may serve to store groundwater before releasing it to lower units, thereby more uniformly distributing recharge to the underlying carbonate units. The water-level records in study area wells will help advance the understanding of the groundwater flow system characteristics related to recharge and discharge.©.4.S Site Conceptual Hydrogeologic Model
This section summarizes what is known or inferred about the hydrologic system in the Pohatcong Valley, particularly in the study are, including: hydrostratigraphic units; hydraulic properties of the geologic materials; groundwater recharge; groundwater flow directions; and groundwater discharge. In a qualitative manner, this information enables speculations to be made concerning the possible pathways that contaminants may travel in groundwater, where the potential sources might be, and where the most strategic locations would be to characterize background chemistry, locate downgradient sentinel wells, and to estimate the extent of contamination.
There are over 300 domestic, industrial, and environmental monitoring wells located within or adjacent to the study area. Information from many of these wells, such as drill logs, were used to develop the conceptual groundwater model presented in this document. Many of these wells have also been sampled and analyzed during previous investigations, some niore than 10 years p ago. Six plates have been prepared which show locations of known wells within and adjacent to
12 300060 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAIt 037-RI-C0^2 the Study area. Plate 6 shows locations of environmental monitoring wells in the study area. # Plates 7 and 8 show the detailed locations of environmental monitoring wells in Washington and Franklin Townships, respectively. Plates 9 through 11 shows the locations of residential, industrial, and municipal water-supply wells. Detailed locations of these wells in Washington and Franklin Townships are shown in Plates 10 and 11, respectively.O.'^.J.i General Hydrologic Conditions
The Pohatcong Valley is a long, narrow, nearly straight valley, extending from the northeast near Karrsville to the southwest near Phillipsburg and Alpha, where Pohatcong Creek flows into the Delaware River. The valley is about 18.5 miles long and about 1.0 to 1.5 miles wide. The Valley is bounded by Oxford Mountain on its northwest flank and by Pohatcong and Upper Pohatcong Mountains on its southeast flank. The Borough of Washington and the designated study area lie in the upper Pohatcong Valley. The floor of the valley lies at about 600 feet above mean sea level (ft msl) at the upper end of the valley, 500 ft msl near Washington, and about 100 ft msl near the mouth of the creek. Elevations rise to 900 to 1,000 ft msl along the crests of the ridges on both sides of the valley near Washington (Figure 1-2).
' The average annual rate of precipitation in the upper part of the Valley is 42 inches. Of this amount, about 48% falls during the growing season (May through September). Based on annual flow rates in rivers in this region, it has been estimated that about 18 to 19 inches (43 to 45%) of the precipitation discharges to the rivers as runoff and baseflow. About 55 to 57% of the precipitation is released back to the atmosphere as evapotranspiration. With 18 to 19 inches of precipitation reaching streams annually, perfiaps half of this amount may be baseflow and half ^w may be direct runoff. Therefore, the long-term average recharge rate to groundwater over the area may be about 9 to 10 inches per year, which eventually reaches streams as baseflow. Recharge rates in flat areas with sandy soils will be much higher than steep flanks of the ridges underlain by crystalline gneiss. Thus, die spatial distribution of groundwater recharge within the study area is not uniform.
EPA, in coordination with die United States Geological Survey (USGS) and the Conti:actor, will conduct detailed evaluations of the hydrogeological character of the Site. As a part of the conceptual model development, the USGS, EPA and the Contractor will evaluate in detail, recharge characteristics within the Pohatcong Valley. The hydrograph separation technique will be used (provided sufficient historical stream flow data are available) to estimate an average value of recharge within the valley. In addition, a simple water balance approach (e.g., Thomthwaite and Mather, 1955) will be used to assess the expected range of spatial recharge variation.
In the Pohatcong Valley study area, the ridges forming the valley walls are composed of Precambrian gneiss, with Cambrian Hardyston Quartzite near the base of the valley walls (see Plate 5). Both of these geologic units are very dense and their primary porosity and permeabilities are relatively low. Only when they are extensively fi^ctured and weathered will they yield significant amounts of water to wells. Because the relative transmissivities of these rocks are so low compared to the geologic units in the valley, they are considered aquitards (and m
13 300061 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-C0-02 « significantly reduce the volume of groundwater which flows through them in comparison to the geologic units in the valley). Because they are aquitards of such low transmissivity, they significantly reduce the possibility that groundwater flows from Pohatcong Valley, beneath the ridges, and enters the groundwater flow system of another valley (i.e., chance of interbasin transfer is minimal). However, the upper surface of the bedrock is weathered and the ridges are mantled with a thin veneer of rcgolith (broken rock) and residual soils. These materials may be permeable and would allow infiltration of precipitation and transfer of water in the shallow soil layer down the ridge slopes and toward the valley bottom.
The geologic units of primary importance to the groundwater system occur in the valley bottom and include the unconsolidated glacial deposits and the underlying Cambrian- Ordovician limestones and dolomites. As discussed above, the bedrock has been intensely folded, faulted, and fractured. As a result of groundwater flowing through these fractures, the carbonate rocks have gradually weathered and chemically dissolved along the fractures, thus widening fractures, increasing permeability, and increasing groundwater flow along the fractures. It is not known exactly how "cavernous" the carbonate rocks may be under the valley, but drillers' logs for wells installed in the area indicate weathered limestone mixed with sand and gravel, loss of circulation, and broken rock, suggesting that the upper 20 to 50 feet of the carbonate bedrock surface may be broken, weadiered, and very permeable. Drillers' logs indicate that the overlying glacial deposits, for the most part, are silty sands and gravel. The unconsolidated glacial deposits should also be relatively permeable and will transmit groundwater flow readily. The hydraulic characteristics of the glacial materials and the carbonate bedrock are discussed in greater detail in # Sections 0.4.5.2 and 0.4.5.4, respectively.©. 4.5.2 Thickness And Hydraulic Properties Of The Glacial Deposits
The glacial deposits consist mostly, if not entirely, of unsorted silty sandy till. There are zones of material occasionally encountered by drillers which were described as coarse sands and gravels; these might be glacial outwash or kame terrace deposits. There are also sections of drill logs described as silty clays which may be interpreted as fine-grained till or may indicate the possible presence of small isolated lacustrine deposits (i.e., deposits in a proglacial lake). However, none of the logs indicated the presence of varves or other stratification features; therefore, the likelihood of lacustrine deposits being present in the valley appears to be rather small. Based on the information contained in the drillers' logs, it is not possible to speculate concerning layering or spatial subdivisions within the glacial deposits at this time.
The thickness of the glacial deposits range from zero near the margins of the valley to roughly 150 feet near the centeriine of the valley. On drillers' logs, it is difficult to differentiate between boulders and rock fragments in till versus sand and gravel within a highly weathered bedrock matrix. Hence, the interface between the glacial deposits above and the weathered bedrock below can not be easily ascertained, especially when a mud rotary or air rotary drill rig is used for drilling and the hole is logged with just drill cuttings.
# 0.4.5.3 Recharge, Movement, And Discharge Of Groundwater In The Glacial Deposits
^'^ 300062 Pohatcong Valley Groundwater Contamination Site . May 1999 Statement of Work WA# 037-RI-CO-^ The overall recharge rate to the groundwater system is estimated to be roughly 9 to 10 inches i per year over the entire watershed. Furthermore, the recharge rate of the valley floor is considerably higher in comparison to recharge rates occurring along the crests and slopes of the ridges.
Recharge water flows downward until it encounters the water table surface. Shallow monitoring wells in the vicinity of Washington have been installed for various environmental investigations, and have shown that groundwater can be encountered at relatively shallow depths. As an example, one monitoring well installed at Agway Petroleum, Inc., on Rt. 31 in Washington was installed to a depth of 7 feet and the static water level after drilling was reportedly 5 feet below ground surface (ft bgs). Seven other monitoring wells at this location were 28 to 34 ft deep, and their water levels were reportedly 15 to 24 ft bgs. A 60-ft deep monitoring well at this location had a static water level after drilling of 48 ft bgs. This condition may represent a localized perched interval. However, monitoring wells at otiier sites also indicate that hydraulic heads decrease significantly with depth and there is a strong vertical gradient. The hydraulic gradient is approaching 1 ft/ft in the upper and middle portions of the glacial till. Thus, the prevalent direction of groundwater flow in the till is downward. However, some thin lenses of finer-grained material may cause lateral flow to occur in loc^ized areas or lateral flow to the crefek could occur in some areas. Drillers' logs for several drill holes indicate that the lower portions of the glacial till were dry or only moist. As an example, in the first four monitoring wells installed at American National Can Company, located on Route 31 in Washington, the lower part of the glacial materials were reportedly dry and groundwater was not encountered until the limestone bedrock was penetrated. # The lower till appears to be coarser-grained and includes more gravel and cobbles than the middle or upper portions of the till. The upper bedrock (weathered limestone) should also be extremely permeable and conductive to groundwater flow. Apparently, the permeable base of the till and the weathered limestone are draining water faster than can be recharged from above, thereby resulting in the dewatering of the lower till. The upper and middle portions of the till, and the creek are, in a sense, perched above the main water table in the bedrock at the base of the valley. It is not known whether this condition is widespread throughout the valley.
Toward the south end of the valley (outside the study area), where the till thins and the hydraulic conditions force the groundwater upward, it is likely that the limestone and lower portion of the till are saturated. This will occur where groundwater discharges. In these areas of groundwater upwelling, lateral water movement through saturated sands in the glacial overburden can be significant. In addition, lateral groundwater movement may also be occurring through the Valley v^a\ls.0.4.5.4 Bedrock Beneath The Valley And Hydraulic Properties
According to drillers' logs, the upper 20 to 50 feet of the limestone is broken, weathered, and intermixed with sand, silt, and rock fragments. Generally, the competency of the rock appears to increase and the degree of fracturing decreases with depth. However, even in the "blue-gray unweathered limestone" mentioned in drillers'logs, fractures and "mud seams" commonly occur. Thus, fracturing of the limestone apparently extends deeper than 50 feet below the bedrock surface. #
15 300063 t
Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAff 037-RI-C0-O2
Thrust faults are present in the bedrock on the sides and undemeatii the valley (see Plate 5). f The main faults and other structural features trend NE-SW, parallel to the axis of the valley. According to a structural geology map for Warren County (Monteverde et al., 1994), the Karrsville thrust fault runs down the center of the valley and passes on the northwest side of Washington Borough. Thrust faults can cause extreme fracturing in adjacent rock formations; thus, the limestone may be more severely broken and weathered down the center of the valley or in the vicinity of splay or other faults related to the Karrsville Fault. Because the limestone is buried in the valley by up to 150 feet of glacial deposits, it is not possible to know exactly where specific fault or fracture zones may occur in the valley, or the condition of rock across the valley.
Review of records and site investigation reports for the area have not revealed any pumping tests or other hydraulic testing of the bedrock aquifer, other than well yield tests that drillers often perform when a water supply well is completed. Specific yields from these tests indicate that the limestone is very permeable.O.-^.5.5 Water Levels In The Bedrock Aquifer
Currently, accurate data are not available to draw a potentiometric surface map for the limestone aquifer throughout the valley. However, water levels at isolated locations indicate that flow in the limestone is primarily toward the southwest (downvalley), but also toward the center of the valley. Water level data obtained from the monitoring wells at the American National Can # site in Washington indicate a flow direction toward the southwest. Water levels at the site dropped from 430.95 to 426.83 ft msl across die site on February 5, 1990 (Environ Corp., 1991); the horizontal gradient was about 0.0077 ft/ft. At the Victaulic Company site, located 33,000 feet (6.25 miles) downvalley from the American National Can site, monitoring wells showed a drop of water levels in the limestone from 312.25 to 306 ft msl across the site (Dan Raviv Associaites, Inc., 1989). The hydraulic gradient for the site was approximately 0.004 ft/ft, with flow direction toward the west. Overall, water levels measured at the two sites indicate a total of 125 ft of head drop between the two sites. The gradient between the two sites therefore was about 0.0038 ft/ft. It is fairly certain that groundwater in the bedrock aquifer is flowing downvalley, although the bulk of die flow is probably occurring in fracture zones and permeable weathered zones, so the actual flowpaths of groundwater will not necessarily be linear but will follow preferred pathways. 0.4.5.6 Recharge, Movement, And Discharge Of Groundwater From the Bedrock Aquifer
The limestone aquifer receives most of its recharge from the glacial materials deposited on the valley floor. Some amount of water is also recharging the aquifer from the gneiss and the quartzite in the valley walls, but this recharge rate is very minor compared to the rate being recharged from the glacial deposits. As discussed above, water in the limestone is probably moving toward the center of the valley and downvalley at a relatively rapid rate. The velocity of groundwater movement in the limestone cannot be calculated with any degree of accuracy without further investigation, but is probably greater than 0.5 ft/day (180 ft/year), assuming p minimum values of hydraulic conductivity to be 10 ft/day and an effective porosity of 0.10.
I ^^ 300064 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-CO-02 0.4.5.7 Groundwater' Surface Water Interchange
As discussed in Section 0.4.5.3 Pohatcong Creek may be a losing stream over much of the upper and middle sections of the valley (including the study area), meaning that it is losing water to the groundwater system. The presence of weUands scattered throughout the valley suggests that there may be some localized areas where groundwater is discharging into Pohatcong Creek. However, it is also possible that the wetlands are localized areas un Groundwater contamination data in the study area have been collected from the late 1970s to the mid 1980s by NJDEP and the Warren County Health Department, and through the 1990s by the American Water Company. The contaminants detected most frequently and in the highest concentrations are TCE and PCE. Other previously detected VOC contaminants include: carbon teti-achloride; 1,2-dichloroethylene (DCE); 1,1,1-trichloroetiiane (TCA); 1,1,2-TCA, 1,3-dichlorobenzene; chloroform; 1,1-dichloroethane (DCA); methylene chloride; and vinyl chloride, and BTEX compounds (including benzene, toluene, ethylbenzene, and xylene). Some semivolatile organic compounds (SVOCs), including bis(2-ethylhexyl)phthalate and di-n-octyl phthalate, have also been detected in groundwater in the PVGCS study area. It is currently unknown whether inorganic contaminants are dispersed throughout the aquifer as well. However, at some PSA-specific locations, inorganics have been detected above risk based screening levels. These inorganics include antimony, arsenic, beryllium, chromium, copper, lead, and vanadium.0.4.6.2 Soil Based on the results of tiie 1997 file review, site levels of VOCs, SVOCs, and inorganic contaminants have been detected above risk-based screening levels at PSA-specific locations. Due to the limited amount of soils data, it is unknown if these contaminants are dispersed throughout the valley. A preliminary review of site-related analytical data indicated that contaminants detected in soil appear to be consistent with those contaminants found within the groundwater. These compounds include PCE, TCE, DCE, BTEX, some semivolatile compounds, and metals. Table 2-1 presents the volatile, semivolatile, and inorganic contaminants detected in environmental media at the site. 0.4.6.3 Historical Uses Chlorinated organic chemicals such as TCA, TCE, PCE, carbon tetrachloride, and chloroform are used as solvents by a wide variety of industries. Carbon tetrachloride was the first chlorinated solvent to be produced in the United States, with production beginning in 1906. 17 300065 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-C0-O2 # Production of TCE and PCE began in 1923. In the 1930s; PCE became a popular dry cleaning fluid. In the post-World War II era, TCE and PCE were used by many industries, including automotive servicing, electronics, instrument manufacturing, aerospace, photographic processing, printing, textile production, and chemical synthesis. The applications in which the greatest amounts of PCE are utilized are dry cleaning/textile production, chemical production, and metal cleaning/degreasing. Metal cleaning and degreasing account for most of the TCE used (Pankow and Cherry, 1996). Large amounts of these chemicals have been manufactured, transported, used, disposed of, and released to soil, air, groundwater, and surface water. In Europe and the United States, chlorinated solvents are frequently the most common industrial contaminants in groundwater.©.4.6.4 Fate And Transport Chlorinated hydrocarbons generally are soluble in water, however they can exist as a dense (denser than water) non-aqueous phase liquid (DNAPL). Solvents in groundwater can pose serious problems, both to drinking water sources and to remedial efforts. One of the reasons solvent-affected aquifers are difficult to remediate is the many ways that solvents in the subsurface can contribute to groundwater contamination. Chlorinated solvents exist in the subsurface in four different phases: (1) as vapors in soil gas; (2) adsorbed onto geologic media; (3) dissolved in water, and (4) as an immiscible liquid (DNAPL). Solvents which are adsorbed onto soil particles are considered immobile, but in other phases, solvents in subsurface media can migrate both laterally and vertically. # A number of factors affect the migration of chlorinated solvents in the subsurface, including: the amount of solvent released; the rate of release; the duration of the release; the properties of the soil, subsoil, and bedrock; and subsurface flow conditions (Cohen and Mercer, 1993). In the vadose zone, gravity causes the dowriward movement of chlorinated solvents in the liquid phase, which flows selectively along coarser-grained layers. In addition to vertical migration, solvents usually migrate horizontally due to capillary forces and soil layering. As it migrates downward, the solvent displaces air and water trapped in interstitial pore spaces to a certain degree, and becomes ti:apped in those pore spaces as a function of surface tension and density. This "residual saturation" occurs when the liquid solvent becomes discontinuous and is immobilized by capillary forces. Residual saturation occurs in the vadose zone, but is greatest in the saturated zone (Huling and Weaver, 1991). The residual chlorinated solvent may continually contribute to groundwater contamination by slowly dissolving into infiltrating recharge water. Some solvent will also volatilize and form a plume of solvent vapor in the soil gas surrounding the source material. The vaporized solvent can migrate laterally through the vadose zone, dissolve into infiltrating water, and percolate down to the water table, thus contiibuting to groundwater contamination. Many chlorinated solvents degrade in subsurface environments under either aerobic and/or anaerobic conditions. Aerobic conditions usually occur in soils above the water table and to ^? some lesser extent, in shallow groundwater where the water table fluctuates or where 18 300066 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAft 037-RI-CO-Q2 groundwater recharge occurs. Aerobic conditions can accelerate the degradation of # contaminants; however, anaerobic conditions are much more prevalent. A common anaerobic degradation example would be TCE and PCE which can be reductively dechlorinated to dichloroethylene and vinyl chloride through microbial transformation, or biotransformation (Pankow and Cherry, 1996). Biotransformation occurs when subsurface microbes create conditions which favor a chemical reaction or when the microbes metabolize the contaminant itself. However, the daughter products which form as a result of biotransformation may be equally unwanted (Mercer and Cohen, 1990). During the degradation of PCE, 1,2-DCE and vinyl chloride are typically produced. Vinyl chloride, a known carcinogen, decays at a relatively slow rate. Table 2-2 lists the chlorinated solvents found in the study area and the range of biodegradation half-lives that are cited in the scientific literature. The ranges of values are large and indicate tiiat degradation rates are highly dependent on the experimental or field conditions under which they were measured. Generally, the short half-lives (fast degradation rates) are associated with laboratory experiments where microbial growth conditions were ideal and degradation rates were maximized. The larger half-lives listed in Table 2-2 may be closer to the half-life values representative of site conditions which are not ideal. As shown in Table 2-2, methylene chloride has the shortest estimated half-life and should theoretically degrade the fastest. Conversely, chloroform, 1,2-DCE, TCE, and vinyl chloride are much slower to biodegrade. Another major factor which will affect the fate and transport of contaminants in the subsurface is the relativedegre e to which they sorb to the geologic materials as they migrate through the subsurface. Chemicals which tend to sorb strongly to the aquifer material tend to # move very slowly and are, for practical purposes, nearly immobile. Other chemical species sorb very little and move quickly through a groundwater system, sometimes at the same velocity as water. Organic chemicals tend to sorb to organic matter in the aquifer materials. Therefore, the fraction of organic matter (foe, diraensionless) in the aquifer has a great effect on the degree of sorption that occurs. Each chemical compound has a relative affinity for sorption to the organic matter and this is termed the organic carbon partition coefficient (Koc). Compounds with high Koc values tend to sorb the most strongly and thus move the slowest through an aquifer system. a Table 2-2 list ranges of Koc values from the scientific literature (Montgomery, 1996, Cohen and Mercer, 1993, Fetter, 1992, Mercer and Cohen, 1990). Carbon tetrachloride, PCE, and 1,1,1-TCA tend to sorb to organic matter, while TCE, 1,1-DCA, 1,2-DCA, and vinyl chloride are least sorptive and are expected to move quicker through geologic materials. The distribution coefficient (Kd) for a chemical is equal to the Koc* times the organic carbon content; this is a measure of partitioning between the aquifer material and groundwater. Ranges of Kd values are estimated for each organic compound appearing in Table 2-2 assuming the foe \j> in an aquifer is equal to 0.2% (this volume is in the range commonly determined for glacial tills and sedimentary rocks). Values for the retardation factor (R) for each constituent are also presented in Table 2-2, assuming the effective porosity (0 of the aquifer material is about 0.30 and the dry bulk density (r) is about 1.8 mg/cm3. The higher die retardation factor, the slower a constituent will migrate through an aquifer. Dividing 1 by R gives the velocity that a constituent will migrate relative to water velocity. So for carbon teti-achloride, its velocity will be somewhere between 16 and 50% the velocity of water. Vinyl chloride has the smallest retardation factor (1.03) and moves nearly as fast as groundwater flow. TCE moves roughly f 19 300067 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAU 037-RI-C0-O2 * 50% as fast as water (R is about 2.0, Table 2-2). 0.5 FREUMINARY HUMAN RISK ASSESSMENT A preliminary assessment has been conducted to determine whether the potential exists for a f threat to human health and the environment due to the Pohatcong Valley Groundwater Contamination Site in Warren County, New Jersey. This preliminary assessment only qualitatively discusses the potential threat to human health and the environment because very § limited chemical data are currently available. There is a need to expand the testing program to define the potential source areas and to better characterize the extent of contamination in groundwater, such that risks associated with exposure to chemicals of potential concern in § affected media may be evaluated. Characterization of risks at the site will proceed in two phases. Using data collected during Phase I of the RI, soil samples from individual PSAs will be screened using risk-based criteria (EPA's Soil Screening Levels [SSLs] for human health and DOE's Preliminary Remediation Goals for Ecological Endpoints [PRGs] for ecological risks). f Results of the screening will be used to identify PSAs requiring broader investigation. For Phase n of the RI, quantitative human health and/or ecological risk assessments will be conducted at § individual PSAs. For planning and scoping purposes, it is assumed that PSA-specific risk p assessments will be conducted at six locations within the Pohatcong Valley Groundwater ContaminatioIn this sectionn Site, potentia. l human health and environmental impacts associated with groundwater and soil contamination at the Pohatcong Valley Groundwater Contamination Site are preliminarily evaluated. Insufficient surface water and sediment data were available to make any reasonable assessment on potential site-related contamination in these media. The results of groundwater sampling efforts, which began in 1978, indicated that several volatile organic chemicals (VOCs) significantly exceeded human health based screening levels, including the solvents TCE, PCE, and vinyl chloride. In addition to these VOCs, several other VOCs and a limited number of SVOCs and metals also were identified as exceeding screening levels in well water. Table 2-1 provides a summary of some of the chemicals identified during historical groundwater sampling activities and maximum concentration levels, where available. At present, an area of 8.75 square miles is believed to be potentially impacted by contaminated groundwater, which is designated a sole-source aquifer for this region. The full extent of the problem is not totally defined at present. The bulk of the sampling and analyses conducted thus far specifically for die Pohatcong Valley Groundwater Contamination Site has been for groundwater. Analytical data for soil were extremely limited and were obtained from State reports. Nevertheless, the available soil data collected from various sites within the study area indicate that several VOCs and metals were detected at concentrations exceeding health-based levels and therefore may be of concern at the site. However, it should be noted that the preliminary nature of the soil data precludes making any conclusions regarding an association between the chemicals in soils exceeding screening w levels and the groundwater chemicals of potential concern. 20 300068 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAIt 037'RI-C0-02 In the following sections, a preliminary assessment for the potential for exposure to # chemicals associated with the Pohatcong Valley Groundwater Contamination Site is conducted. The migration of chemicals within groundwater and between groundwater and soil and the other M media to potential exposure points is also discussed below. Potentially exposed populations and • possible exposure pathways are identified and risks are preliminarily characterized. Data needs for the risk assessment to be performed as part of the RI are also presented.O.S.l Potential M Source Areas * The sources of groundwater contamination in the study area are not known. Potential W sources include industries, waste disposal areas, and uncontrolled dumping areas. There are ^ several potential source areas in the Pohatcong Valley region. The identification of sources M contributing to groundwater contamination is one of the major purposes of the RI. ^ 0.5.2 Migration Pathways ® A migration pathway describes the movement of a chemical from a source to a receptor. * Although the specific sources of the chemicals of potential concern at the Pohatcong Valley site ^ have not been determined, the presence of die chemicals in groundwater indicates that direct V releases to groundwater or indirect releases from soil to groundwater have occurred. Because the ™ VOCs detected in the groundwater are soluble and have a moderate to low propensity for binding ^^ to organic material, these chemicals may be transported relatively freely in groundwater ^B depending upon die amount of organic carbon in the aquifer material. Section 0.4.6.4 presents a ^^ description of the fate and transport of solvents in groundwater. In addition, the limited data -^ indicate the presence of SVOCs and inorganics in groundwater. These compounds are expected H to be transported to a more limited degree because these chemicals are less soluble and have a ^ higher tendency to adsorb to particulate matter or to precipitate out of solution. Any chemicals ^ transported in groundwater generally will follow hydraulic gradients and move toward pumping m sources. The following sections describe the primary migration pathways for contaminants in groundwater to the other evaluated media. ^ Migration from Groundwater into Surface Water. Soil and Sediment ^ Chemicals migrating in the groundwater may reach receptors via drinking water wells, seeps, ^ or by discharge of groundwater to surface water. At present, groundwater discharge to nearby n streams such as the Pohatcong Creek or to other surface waters of the area is expected but not known. Due to the lack of adequate surface water, soil and sediment data, migration of ^ groundwater chemicals to surface waters or sediments is not considered in this preliminary risk ^ assessment. Potential exposures and risks associated with site-related chemicals in surface water, soil and sediment will be evaluated in the RA performed during the RI. m Migration from Soil and Groundwater into Air 21 300069 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAU 037-RI-C0-02 Chemicals in the groundwater and soil may volatilize to air and thereby reach potential receptors. Volatilization is not expected to be a dominant process for the removal of organic chemicals from deeper soils or from groundwater. However, some portion of the potential I chemicals of concern will partition from groundwater to the soil pores. The presence of elevated concentrations of PCE (up to 561.4 ppb) and TCE (up to 770 ppb) in groundwater indicates that partition to soil-air space may occur to some degree, either from groundwater or from I contaminated soils. Chemicals in soil gas are available for movement through the soil pore space to the ambient atmosphere or into building basements, under appropriate conditions (e.g., I presence of sumps in basements, small cracks in foundation walls). I Migration from Groundwater into Soil Chemicals associated with the groundwater may have originated from contaminated soils at I discharge points. There is a moderate to low likelihood of volatilization and subsequent contamination of soils from the VOCs found in the groundwater depending upon the individual constituent's affinity to adsorb onto soil. However, other chemicals identified as exceeding t screening levels (i.e., SVOCs, metals), which have higher affinity to adsorb onto soil, could I come into contact with soils and result in soilcontamination. 0.53 Routes of Exposure, Potential Receptors, and Preliminary Assessment of Risk Potential routes of exposure to human and non-human (i.e., ecological) populations are I discussed below by exposure medium, along with a preliminary characterization of risk. t Groundwater Potential exposures from contaminated groundwater inclutte ingestion of contaminated I drinking water, dermal exposures during bathing or other household use of groundwater, and inhalation of chemicals released from water diuing cooking and showering. Groundwater has been the major source of potable water in the Pohatcong Valley and is also used for commercial I and industrial purposes. Washington Borough currently operates two wells (Vannatta Street and Dale Avenue). The Dale Avenue well is reportedly used only during emergency demand situations. Vannatta Street well water is treated by an activated carbon absorption process before I distribution to its users. The two wells supply water to a majority of the residents within the site. Reportedly, the New Jersey Water Company tests the effectiveness of the carbon treatment I system twice per month, analyzing for VOCs. Their test data indicate removal of PCE and TCE to the NJ MCL of 1 ppb and, in some cases, to non- detectable levels. Other VOCs were reportedly removed as well, to below their detection limits. Thus, public water supply users are I not currently exposed to elevated levels of VOCs of potential concern in the groundwater. Public water supply users could be exposed to higher levels of VOCs in groundwater if the treatment system failed, although such exposures would likely be limited to short-term exposures # since the system is tested monthly for "breakthrough." These users also may be exposed to 22 f 300070 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAU 037-RI-CO-02 elevated levels of certain other chemicals of potential concern such as inorganics where the current treatment system may not be adequate to remove these compounds. The main potential risks associated with exposure to contaminated groimdwater are to the residents within and immediately downgradient of the site who use water from private wells. Several private wells exist in the Pohatcong Valley study area and immediately downgradient of 0 the area. To assist in evaluating potential risks to Unese residents, NJDEP conducted domestic well sampling activities in November 1997 at residential homes within and immediately downgradient of the site. The principal chemicals consistently detected in the groundwater at the site and those 0 significantly exceeding screening criteria (i.e., TCE, PCE, and vinyl chloride) are suspected or known human carcinogens. These chemicals also can act as systemic toxicants, as can other 0 chemicals selected in the groundwater. Historical groundwater data from die wells in the study area indicate concentrations of TCE and PCE above the New Jersey drinking water maximum contamination level (MCL) of 1 ug/L established for these chemicals. TCE and PCE 0 concentrations were also above their Federal MCLs of 5 ug/L, respectively. The detected concentrations of these two chemicals also significantly exceeded their respective health-based C' screening levels of 1.6 ug/L and 1.1 ug/L. In addition, vinyl chloride was detected at a level \^ above the Federal MCL of 2 ug/L and above the health-based screening level of 0.019 ug/L. As noted earlier, several other chemicals, including VOCs, SVOCs, and inorganics, were detected at concentrations significanUy exceeding screening levels; these included benzene, which exceeded P its screening level of 0.36 ug/1, MTBE, which exceeded its screening level of 18 ug/L, chrysene, which exceeded its screening level of 9.2 ug/L, and arsenic, which exceeded its screening level of 0.045 ug/L. Many of the compounds found in the groundwater are potential carcinogens. An additional health concern for the Pohatcong Valley area is that both PCE and TCE can be 1] aerobically biodegraded to vinyl chloride, a known human carcinogen that is more potent than either PCE or TCE, and that has already been detected in the groundwater. Thus, in this case, natural fate processes in the environment could lead to increased risks. Q Air 0 The most probable inhalation exposure pathway for the area is inhalation of VOCs. Any 0 current users of unti^ated groundwater from private wells could be exposed to chemicals that volatilize from groundwater during its use. Public water supply users who rely on the Vannatta Street well also cold be exposed via this pathway if die activated carbon ti-eatment failed; 0 although, as mentioned previously, such exposures would be short term. In addition, persons living or working near potential source areas could be exposed to VOCs that have migrated through soil pore spaces to the ambient atmosphere. 0 VOCs could potentially volatilize from soil or groundwater and reach building foundations. f 23 300071 0 •^L Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-Rt-C0-02 Chemicals in soil gas can migrate into basements through cracks in the foundation or dirough sumps or drains. Residents and other building occupants could be exposed to chemicals that have migrated into the basement or that have dispersed throughout the building. It is not recommended that indoor air sampling be conducted in the RI to assess these potential factors because of the difficulty in ascribing any results obtained to specific sources. Instead, inhalation of dissolved VOCs released into indoor air while showering will be evaluated for adults, while dermal exposures while washing or bathing will be evaluated for both children and adults. This is a more conservative approach for homeowners than modeling air vapor phase transport through soil and foundation materials. In addition to potential exposures via the inhalation of VOCs that have volatilized from soil or groundwater, inhalation exposures also could occur if soil particles were suspended in air and subsequenUy inhaled. This would occur most readily in areas that are not paved or grassy, and in areas where soils being turned over (e.g., at construction sites). Soil The two major pathways by which humans may be directly exposed to chemicals of potential concern in soil are dermal absorption and incidental ingestion of chemicals from direct contact with soils. Exposed populations could include workers, and child and adult residents having P contact with these soils. Initial and limited preliminary soil data have indicated that several VOCs (including toluene, which significantly exceeded its screening level of 1,600 ppm) and metals (including arsenic, which also significanUy exceeded its screening level of 0.43 ppm) have been detected at several sites in the study area at concentrations exceeding health-based screening levels. In addition to RI sampling for the surface soil, subsurface soil samples will be collected so that exposures that could occur to individuals who excavate soils to the depth of groundwater may be evaluated. These individuals would include workers engaged in construction of buildings such as homes, office buildings, and shopping centers. Other Site-Related Risks 9 Based on die site conceptual model described in Section 0.4.5, it is possible that ,4 contaminated groundwater is discharging (or may discharge) to surface water. Therefore, J potential human health risks associated with contacting this media will need to be evaluated. Additionally, potential ecological impacts will need to be quantitatively and qualitatively evaluated in a screening level ecological risk assessment (ERA). The ERA will focus on '| whether any of the groundwater chemicals of potential concern are available to reach various ''| types of aquatic receptors such as fish and benthic macroinvertebrates inhabiting ponds and the Pohatcong Creek, Shabbecong Creek, and their associated wetlands. .1 W^ 0.S.4 Public Health and Environmental Assessment Data Needs >il 24 300072 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAff 037-RI-C0-02 Additional information is required to evaluate the potential risks to human health associated with the groundwater exposure pathway and to screen potential risks posed by other contaminated media, including surface water, sediment, and soil. Additional sampling of groundwater, surface water, soil, and sediment is needed so that the full extent and magnitude of contamination can be determined. In addition, background samples of these media are required so that site-related chemicals can be identified. Groundwater sampling will include groundwater from available private wells, PSA locations, and raw and treated water from the Washington Borough supply system. For all media, the analytical detection limits must be equal to or below their respective health-based screening levels. The screening levels for groundwater and surface water are presented in Tables 2-3 through Table 2-5. The screening levels for soils and sediments are presented in Table 2-6 dirough 2-8. 0.6 PROBLEM SUMMARY VOC and semivolatile organic contamination (SVOCs) has been documented in environmental media at the Pohatcong Valley Groundwater Contamination Site. The potential exists that other contaminants such as metals may also be present in the environmental media. Approximately 58 potential source areas (PSAs) have been identified that may be contributing to die groundwater contamination. The potential also exists for privately owned septic systems and municipal sewer lines to be contributing to the groundwater contamination. The total area of concern is very large (approximately 5,600 acres) and encompasses two townships and one borough. A domestic well survey conducted for the PVGCS by ICF Kaiser revealed that several private domestic wells have been installed downgradient of the site. It is currentiy unicnown whether contaminants found in groundwater at the site have migrated toward these newly installed wells. It is also currently unknown whether ecological receptors are being impacted by contamination detected at the site. 0.6.1 Site Investigation Plan A Draft Site Investigation Plan (SIP) was submitted to EPA, NJDEP, and USGS on 29 September. The Draft SIP presented ICF Kaiser's recommendations for investigating the site, including the identification of: possible contamination sources; sampling methodologies; the number, type, and location of environmental media samples; investigatory limitations; and possible problems such as site access and facility cooperation. The Draft SIP was revised based on EPA's comments and additional information obtained from an NJDEP file review. The Draft P 25 I 300073 f Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA» 037-RI-CO-02 Final SIP (included as Appendix A to the Draft Work Plan) presented the detailed information regarding the PSAs proposed to be investigated, and the rationale for selecting the locations and types of environmental media samples. The SIP has been incorporated into this Final Work Plan. Plate 12 presents the locations of the sites within the PVGCS which were identified during the 1997 File Review and the 1989 IS. Table 3-1 presents the site names, their address, and the lot and block number. Plates 13,14, and 15 present the location of sites which were subsequendy identified as PSAs within the PVGCS. The methods used to identify potential source areas (PSAs) and the potential sources identified are described in the following sections. 0.6.1.1 Methodologies For Identifying PSAs 1989 Industrial Surveys In 1989, ICF Kaiser performed field surveys at industrial facilities identified in ICF Kaiser's February 1989 Interim Report and located within the Pohatcong Valley area. The purpose of the surveys was to refine the list of potential source areas which could have caused the groundwater contamination within the PVGCS. During the course of the IS, additional PSAs were identified p and investigated. No field sampling activities were performed during the industrial surveys. Based in the IS findings, sites were either added to or removed from the PSA list. Of die 76 PSAs investigated during the IS of May, June, and July of 1989,53 sites were considered to be potential sources and 23 sites were considered to be unlikely sources. One map and a summary of the IS findings were generated for each of the 53 PSAs identified in the IS. The IS findings and maps were included in ICF Kaiser's 1997 file review and are included in Appendix A of this Work Plan. 1997 File Review ICF Kaiser performed a file review of reports and data obtained from EPA, NJDEP, Warren County Health Department (WCHD), and ICF Kaiser's chronological file. The file review commenced with visiting the offices of the above noted agencies, and making copies of the files. Information about each site identified within the PVGCS area was then organized, cataloged, and reviewed. That information was dien summarized into a standard format and is included as Appendix A of this report. 0.6.1.2 Recommended Actions For PSAs The recommended actions included in the SIP for sites identified as PSAs in the PVGCS and p the criteria used by for selecting the action are described below. ^^ 300074 1 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-CO-02 4 0.6.1.2.1 PSAs Requiring Field Investigations I Sites were recommended for inclusion in the field investigation portion of the RI if: 1) solvents were detected in environmental media on site; 2) solvents were reportedly used on site; I 3) activities were conducted which commonly use solvents; or 4) waste materials were reported to have been disposed of at a site. Si Solvents Detected in Environmental Media On-Site I Sites within the PVGCS area were characterized as PSAs requiring a field investigation if analytical results from sampling programs indicated the presence of solvents in environmental I media on site. Examples of sites included in this classification include BASF and American National Can. The rationale is that documented solvent concentrations in media could indicate the presence of a potential source area on-site and contaminant releases to the environment. I PSAs requiring a field investigation under this category and the recommended investigatory program are presented in Table 3-2. I Solvents Reportedly Used On-Site 4 Sites within the PVGCS area were characterized as PSAs requiring a field investigation if the facility reported solvent use in the Request for Information forms submitted to EPA or in other documentation obtained by ICF Kaiser. The rationale for classifying facilities which use I solvents as PSAs is that contaminant releases could have occurred at the facility and sampling activities are needed to determine whether proper management of solvents and solvent contaminated wastes has occurred at the facility. PSAs requiring a field investigation under this category and the recommended investigatory program are presented in Table 3-3. I Activities Which Commonly Use Solvents I Sites within the PVGCS area were characterized as PSAs requiring a field investigation if the reported operations use solvents. Examples of industiies which commonly use solvents are automotive facilities such as gas stations or autobody centers. The rationale for classifying industries which commonly use solvents as PSAs is that solvent use likely occurred and sampling activities are needed to determine whether proper management of solvents and solvent contaminated wastes has occurred at the facility. PSAs requiring a field investigation under this category and the recommended investigatory program are presented in Table 3-4. I Sites Which Reportedly Received Waste Materials for Disposal I 27 300075 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAit 037-RI-C0-02 p Sites within die PVGCS area were characterized as PSAs requiring a field investigation if there were reports (either written or documented verbal accounts) of waste disposal activities occurring at the property. These sites include die High Point Sanitary Landfill. The rationale for classifying these sites as a PSA is that die type and quantity of waste material reportedly disposed of at the Site is unknown and requires investigation. PSAs requiring a field investigation under this category and the recommendedinvestigator y program are presented in Table 3-5. 0.6.1.2,2 Sites Requiring Site Inspections Some sites, including examples such as Apple Orchard Dump and Mueller Roofing, are classified as sites requiring an inspection because the 1989 SI and/or 1997 File Review findings were inconclusive and a site inspection was determined to be required to refine observations and file review findings. Sites recommended for inspection are presented in Table 3-6. Sites identified in this table will, after access agreements are secured, be visually inspected and recommendations made as to whether field investigations are necessary. 0.6.1.2.3 Sites Requiring No Further Action Sites identified within the Pohatcong Valley which require no further action (NFA) are presented in Table 3-7. These sites, based on the available information, do not appear to be sources of TCE and PCE groundwater contamination in the Pohatcong Valley. 0.6,2 Hierarchical List of PSA Sites Based on information obtained during the 1989 Industrial Survey and 1997 File Review, a Hierarchical List of PSA Sites was developed. The purpose of the list is to present a ranking of the sites which, based on die information obtained to date, are likely sources of contamination at the PVGCS. This list will require modification as new data are generated during the course of the Phase I RI. The Hierarchical List of PSA Sites is presented in Appendix B. O.O Preliminary IdentiiFication of Potential Remedial Techinologi(^ 0.6.3.1 General Response Actions As required by SARA and the NCP, General Response Actions will be considered at the Pohatcong Valley Groundwater Contamination site for all remedial action objectives. General Response Actions are broad remedial approaches capable of meeting the remedial objectives at ^^ die site. Some response actions are sufficiently broad such that they are capable of meeting remedial objectives alone. However, in most cases, combinations of response actions are 28 300076 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 required to address various Site conditions and to be effective in meeting the remedial goals. The General Response Actions appropriate for the site are: No-Action Institutional Controls Containment Removal Treatment Disposal No Action The NCP and CERCLA require the evaluation of a no-action response measure as a basis of comparison with other remedial alternatives. The no-action responsemeasur e is used during the risk assessment to project potential future risks at the site. The no-action response measure is intended to allow comparison of those future risks with the residual risks associated with other response measures. While the No Action alternative must be compared with other alternatives as part of the FS procedure under SARA, it is not a solution to die problem at the site. Restricted Access/Institutional Controls Institutional controls include actions that control human contact with the contamination rather than controlling the contamination present in the media. These actions may be physical, such as fences or barriers, or administrative, including establishment of zoning restrictions, land use restrictions, or notices upon resale or transfer of property tide. In 1985, NJDEP preliminarily delineated the spatial extent of groundwater pollution in Pohatcong Valley in die form of a Well Restriction Area (WRA). Although diis WRA does not encompass the entire study area, it is the first step in terms of Restricted Access/Institutional Conti-ols. It requires long-term monitoring. Containment Containment technologies control potential hazards by reducing the ability of a chemical to leave the source and enter the transport medium or leave the transport medium and contact a receptor. Containment technologies can reduce contaminant mobility, and in some cases can reduce contaminant toxicity and volume. These technologies may require monitoring to determine whether remedial measures are remaining protective of human health and the 29 300077 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAff 037-RI-C0-O2 environment. Removal Removal technologies refer to methods typically used to extract impacted groundwater, or to excavate and handle soils, wastes, and other materials. Extraction and excavation technologies provide no treatment of wastes, but may be employed prior to treatment or disposal technologies. Treatment Treatment technologies reduce the volume, toxicity, or mobility of contaminants by biological, physical, thermal, or chemical processes. Treatment technologies may be performed ex-situ or in-situ. Treatment to reduce volume includes extraction procedures to concentrate contaminants and in-situ procedures (i.e., bioremediation, enhanced volatilization) to reduce waste volume. Treatment to reduce toxicity includes methods to destroy or modify the properties of chemical to render it less harmful. Treatment may include methods to modify the physical or chemical properties of die waste or impacted media to reduce mobility. Treatment may also include methods to modify the physical or chemical properties of the waste or impacted media to promote mobility of a waste for the purpose of collection and reduction of the waste, or to p promote attenuation. Disposal Disposal technologies are primarily designed to reduce die mobility of contaminants, generally by application of containment technologies. Remedies requiring the off-site transportation and disposal of wastes can only be implemented if wastes are disposed of in a facility operating in compliance with RCRA. Disposal technologies are applicable to both hazardous wastes, which may be disposed of in a RCRA SubtiUe C landfill, and non-hazardous wastes, which can be disposed of in a RCRA Subtitle C or D landfill. I 0.6.3.2 Potential Remedial Technologies Table 3-8 and Table 3-9 present the general response actions identified above, the potential remedial technologies included under each action, a description of the technology, and each technology's ability to remediate contaminated media. i 0.6.4 ARARs and Guidance To Be Considered Applicable, Relevant, and Appropriate Requirements (ARARs) and other guidance to be ;1 ^° 300078 B Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-C0-02 considered (TBCs) are used to: 1) Develop remedial action objectives and determine the 4 appropriate extent of cleanup, 2) Scope and formulate remedial action alternatives, and 3) Govern implementation and operation of the selected remedial action alternative. This section provides a preliminary determination of the federal and state environmental and public health requirements that are applicable or relevant and appropriate to the Pohatcong Valley site. In addition, this section presents an identification of other federal and state criteria, advisories and guidance that could be used for evaluating remedial alternatives to be developed in Q dieFS. 0 0.6.4.1 Definition of ARARs and TBCs SARA defines an ARAR as: 0 Any standard, requirement, criterion, or limitation under any federal environmental law; and Any promulgated standard, requirement, criterion, or limitation under a state Q environmental or facility siting law that is more stringent than any equivalent federal standard, requirement, criterion, or limitation. 4 The purpose of this definition is to ensure that CERCLA responses are consistent with both ( federal and state environmental requirements. ARARs are classified as either "applicable", or "relevant and appropriate" requirements. Other guidance, advisories, and criteria may be classified as to be considered (TBCs). The r^ following provides a more detailed definition of ARARs and TBCs \ Applicable Requirements n Applicable requirements refer to those Federal and State requirements that would be legally f enforceable within the context of implementation or operation of the remedial action. An example of an applicable requirement would be the Safe Drinking Water Act's Maximum p. Contaminant Levels (MCLs) for a site that causes contamination of a public water supply. Relevant and Appropriate Requirements \ Relevant and appropriate requirements are Federal or State standards, criteria, or guidelines that ^^K are not legally enforceable within the context of implementation or operation of the remedial ^^^ "" 0 ^^ 300079 ^ I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAU 037-RI-C0-02 action, but which address problems so similar to those at the site that their application is appropriate. For example, while RCRA regulations are not applicable to closing undisturbed I hazardous waste in place, the RCRA regulations for closure by capping may be deemed relevant and appropriate. During the RME process, relevant and appropriate requirements are intended to have die same weight and consideration as applicable requirements. I To Be Considered I Other Federal and State guidance documents or criteria that are not enforceable but are advisory and "to be considered" during the FS process. For example, where no specific ARARs exist for a chemical or situation, or where such ARARs are not sufficient to be protective, guidance I documents or advisories may be considered in determining the necessary level of cleanup for I protection of public health and the environment. I 0.6.4.2 Types of ARARs and TBCs Widiin these jurisdictional boundaries, ARARs are further defined according to the activity, contaminants, or locations they are expected to affect. ARARs that relate to the level of pollutant I allowed are called chemical-specific; ARARs that relate to the presence of a specific geographic or archaeologic area are called location-specific; and ARARs that relate to a method of remedial response are called action-specific. These types of ARARs and TBCs are further described p below. I Chemical-Specific I Chemical-specific requirements define acceptable exposure levels for specific hazardous substances and, therefore, may be used as a basis for establishing preliminary remediation goals and cleanup levels for chemicals of concern in the designated media. Final remediation goals will I be evaluated during the FS process. Containment-specific ARARs and TBCs are also used to determine treatment and requirements that may occur in a remedial activity. Potential I chemical-specific ARARs and TBCs are presented in Table 3-10. I Location-Specific Location-specific requirements set restrictions on the types of remedial activities that can be I performed based on site-specific characteristics or location. Location-specific ARARs are triggered when a remedial action infringes on a regulated area. Remedial actions may be restricted or precluded based on Federal and State laws due to the presence of wetlands or I floodplains at or in the vicinity of the site, or due to man-made features such as existing landfills, disposal areas, and local historic landmarks or buildings. Similarly, location-specific ARARs, such as local zoning codes, may be applied in considering remedial actions within the context of appropriate future site use. Potential location-specific ARARs and TBCs are presented in Table ^2 300080 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAU 037-RI-CO-^ 3-11. 4 Action-Specific Action-specific requirements set controls or restrictionso n the design, implementation, and performance of waste management actions. They are triggered by the particular types of treatment or remedial actions diat are selected to accomplish the cleanup. Potential action- specific ARARs and TBCs are presented in Table 3-12. 0.6.4.3 Consideration of ARARs During the RI/FS ARARs and TBCs will be used as a guide to establish the sampling strategy and methods during the RI, and to aid in scoping, formulating and selecting proposed treatment technologies during the FS. They will also be used to govern the implementation/operation of the selected action. Primary consideration should be given to remedial alternatives that attain or exceed the requirements found in ARAR regulations. ARARs and TBCs will be considered at the following intervals during the RI/FS Process: m 1. Scoping of the RI/FS. Identify chemical-specific and location-specific ARARs and TBCs on a preliminary basis, in order to plan the site characterization sampling locations, and analytical Data Quality Objectives. Site characterization and risk assessment phases of the Remedial Investigation. Identify the chemical-specific ARARs and TBC material and location-specific ARARs and TBCs more comprehensively and use them to help determine the cleanup goals. 3. Development of remedial alternatives in the FS Report. Identify action-specific ARARs for each of the proposed alternatives and consider them along with other ARARs and TBC B material. 4. Detailed evaluation of alternatives. Examine identified ARARs and TBC guidance for each alternative as a package to determine what is needed to comply with laws aod regulations and whether or not compliance is expected. 0.6 J Preliminary Remedial Action Objectives Remedial Action Objectives (RAOs) are intended to clearly state the site-specific goals to be 33 300081. Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WA# 037-RI-C0'02 p achieved. Each remedial alternative is evaluated to gauge its ability to satisfy these Site- specific goals. Mitigation of potential health and environmental risks associated with exposure pathways and compliance with State and Federal ARARs comprise the basis of the RAOs. Additionally, consideration is given to the potential impacts of the remediation on designated future land use. Based upon the results, the Preliminary Risk Assessment, and the overall Site physical characteristics, as well as a review of potential ARARs, the following preliminary remedial action objectives have been identified for the site: 1. Remedial actions shall mitigate potential routes of human health and environmental exposure to contaminated media. 2. Remedial actions shall comply with ARARs to the extent practical. 3, Remedial alternative selection shall consider ftiture land use, 0.6.6 DQO Determination Data Quality Objectives (DQOs) are qualitative and quantitative statements that define data 1^^ quality criteria and sampling design performance specifications. ICF Kaiser has implemented the EPA DQO process, as oudined in EPA 540-R-93-071: Data Quality Objectives Process for Superfund, to determine the type, quality, and quantity of data that are required for environmental decision making on this project. Project DQOs related to sampling design include sample collection strategy, the number and locations of field and QC samples, and sample collection methodology. Specifications for sample collection are provided in the Field Operations Plan (FOP) which is die QAPjP. DQOs related to data quality criteria focus on the identification of the end use of die data to be collected and the degree of certainty with respect to selectivity, sensitivity, precision, accuracy, reproducibility, completeness, and comparability necessary to satisfy the intended end use. A description of the sample analysis program ICF Kaiser has developed for this RI/FS SOW in provided in Task 4. Additional information is presented in the FOP. The problem posed by this site is understood to be as follows: ° Groundwater is contaminated with volatile and semi-volatile organic; ° Contaminants in addition to volatile and semivolatile organic compounds may be dispersed in the groundwater, and ^ " Fifty-eight potential source areas have been identified in the study area. w 34 300082 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-C0-O2 ^Km In addition to the potential sources identified, other possible sources of contamination include: ^^ private septic systems and drain lines; municipal sewer lines; and the surface water and sediments ^ in Pohatcong and Shabbecong Creeks and their tributaries. M To address the problems posed by the site, the following objectives have been identified for ra performing the RI/FS: • Identify which (if any) of the potential source areas are contributors to groundwater contamination; Characterize the groundwater contamination in terms of its vertical and horizontal distribution and its chemical composition; Characterize any soil contamination encountered in terms of its vertical and horizontal distiibution and its chemical composition; Assess risks to public health and the environment posed by groundwater and soil contamination discovered; and Assemble and compare remedial alternatives to regulatorycriteri a in order to determine possible remedies for the site. To achieve die above RI/FS objectives, the following groundwater and soil data requirements have been identified: Groundwater ~ Type and ConcenQ-ation of Contaminants; ~ Thickness of Overburden Aquifer, ~ Presence, Thickness and Extent of High Permeability Deposits; ~ Presence, Thickness and Extent of Clay Layers; ~ Presence, Thickness and Extent of Perched Water Tables; ~ Depth to Bedrock; ~ Groundwater Flow Direction; ~ Vertical Flow Gradients; - Flow Characteristics of Overburden Aquifer; ~ EowCharacteristicsof Bedrock Aquifer; — Hydraulic Connection with Surface Water; and ~ Geotechnical, Geochemical, and Other Parameters. Soils ~ Sources of Contaminants; ^P 35 300083 a Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-CO-OZ — Types and Concentrations of Contaminants; — Horizontal Delineation of Contamination; — Vertical Delineation of Contamination; and ~ Geotechnical, Geochemical, and Other Parameters To the extent practicable, these data will be collected during RI field activities. The following table summarizes the project DQOs related to chemical analyses, Symmairy of Data Uses \^:iS':.yi::q, "ifypso^^Analysis r XV "^-^Etettfyaesi^^ Comments o Total and/or o site Characterization Data generated by qualitative •Organic/Inorganic Vapor Detection field instrumentation will be used to Using Portable Instruments o Health and Safety Monitoring During screen soil and water samples for o Field Test Kits Implementation contaminants and to monitor contaminant exposure levels during P field worit. o Variety of Organics by GC; o Site Characterization Analysis of samples for Inorganics by AA, XRF o Evaluation of geochemical parameters such as o Tentative ID; Analyte- Alternatives chemical oxygen demand (COD), Specific grain-size analysis, and total organic cartDon (TOC). The analysis will be o Detection Limits Vary from perfonned at an off-site laboratory. Low ppb to Low ppm 0 Organlcs/lnorganics Using o Risk Assessment Samples collected from IDW m EPA Procedures Other Than CLP; will be analyzed for RCRA Can Be Analyte-Specific o Site Characterization characteristics to determine disposal requirements; approximately 30 o RCRA Characteristic Tests o Evaluation of /Utematives domestic water samples will be analyzed by EPA's ESD laboratory for o Waste Disposal drinking water parameters. 36 300084 e Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAIt 037-RI-C0-O2 To determine the nature and 4 • CLP Organlcs/lnorganics by o Risk Assessment extent of contamination within GCmS; AA. ICP environmental media at the site. All e Evaluation of groundwater, surface water, soil, and I » Low ppb Detection Limit Alternatives sediment samples will be analyzed by EPA's CLP. The risk assessment wilt be based on the analytical results of the groundwater, surface water, soil, I and sediment samples. The method detection limits (MDLs) for sample analysis will achieve levels appropriate for use In the Risk I Assessment. I I 0.6.7 Field Investigation Scope of Work I The general objectives of the RI/FS are: I " To delineate the site-wide groundwater plume at the site in terms of its vertical and horizontal characteristics and chemical composition by sampling groundwater monitoring wells and by installing sampling well points; # To identify potential contaminant source areas; To conduct investigations at potential contaminant source areas to assess I potential impacts to groundwater quality, including soil and groundwater sampling; To evaluate receptors, and assessment of risks, posed by the contamination, I and; To develop and evaluate remedial alternatives which mitigate the risks to I human and ecological receptors posed by contaminated media. I The Remedial Investigation is comprised of two phases. Phase I of the RI field investigation will include a multi-media investigation to identify likely sources of groundwater contamination and to characterize the approximate nature the vertical and horizontal extent of the groundwater contamination in die Valley. I The Phase I RI will include: collection, management, and analysis of environmental samples; reduction and evaluation of data; screening of PSAs from the hierarchical list; characterization of the Valley's hydrogeology; and assessment of wetlands and sensitive ecological habitats. The I identification of PSAs where drilling and subsurface sampling will occur during Phase I will be based on the data obtained during the soil gas investigation and the sampling of existing wells. This data will be used to revise the Hierarchical List of Sites, For the purpose of project scoping I 37 300085 I I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-C0-02 p and cost estimating, it should be assumed that approximately 20 of the original 58 PSAs will require further investigation following the soil gas investigation and the sampling of existing wells. The screening of PSAs and the identification of sites to be investigated during the Phase II RI will be based on analytical data from soil gas investigations, analytical results of samples collected from monitoring and residential wells; and the soil and groundwater samples collected during drilling activities at selected Phase I PSAs. A letter report will be prepared to present the results of the Phase I investigation, identify those PSAs which are considered likely, potential, and not likely sources of contamination, and identify data gaps needed to be filled in Phase II to complete the soil and groundwater investigations, the risk assessment, and the FS. The second phase of the RI (Phase II RI) will focus on investigating areas which were identified in the Phase I RI as likely contiibutors to the Pohatcong Valley site contamination problem, as directed by EPA. The Phase n objectives and scope will be determined based on the Phase I report. For the purpose of project scoping and cost estimating, it should be assumed that approximately 6 of the original 58 PSAs will be identified as potential sources areas in the Phase I report. The Phase n RI will also include tasks that allow for the collection of data which will supplement the data collected during the Phase I RI. If data collected during Phases I and n are of sufficient quality to characterize the vertical and horizontal extent of contamination at the source areas investigated, a human and ecological risk assessment and feasibility study will be p performed. During the Phase I of the RI, up to approximately 1,395 groundwater, soil, surface water, sediment, and QA/QC samples will be analyzed in EPA's Contract Laboratory Program (CLP) for VOC, SVOCs, and metals. Approximately 15 samples will be analyzed for waste characterization parameters by an independent laboratory, and approximately 40 samples will be analyzed for drinking water analysis by EPA's Environmental Services Division (ESD) laboratory. During the Phase II RI, approximately 48 groundwater samples, 144 soil samples and 122 QA/QC samples will be analyzed by EPA's CLP. Approximately 5 waste characterization samples and 10 geotechnical samples will be analyzed by an independent laboratory. The collection of environmental samples and the performance of other activities necessary to complete the field work portion of the Phase I and Phase n RIs are summarized below. Phase I RI Tasks: Task 3.01 (Additional Data Review) - This task was initiated. NJDEP's domestic well sampling results and water quality data obtained from NJ American Water Co. will be reviewed. p Task 3.02 (Fracture Trace Analysis) - Task Completed - Fracture trace analysis involved the I ^^ 300086 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA» 037-RI-CO-O2 interpretation of aerial photographs to identify fractures in bedrock. P Task 3.03 (Cultural Resource Investigation) - A CRI will be performed to determine the presence or absence of documented cultural resources in study area using documentary research. Task 3.04 (Subcontract Specifications) - Subcontract specifications will be prepared, revised, solicited and awarded for several work elements. Task 3.05 (Delineation of Wedands) - Wedands will be delineated prior to sampling at PSAs to avoid impacts to sensitive ecological habitats. Task 3.06 (Survey of Endangered Species Habitat) - Surveys will be conducted at PSAs where potential habitats of the endangered bog turtle & dwarf wedge mussel may be present. Task 3.07 (Mobilization) - This task will include the mobilization of equipment and supplies to the site, and establish the field trailer office. Task 3.08 (Soil Gas Investigation) - Data from this task will be used to screen PSAs for the presence of VOCs in subsurface soils. P Task 3.09 (Sampling of Existing Wells) - Sample data generated during this task will help define the current nature and extent of groundwater contamination in the valley and help identify source(s) of contamination. Task 3.10 (Surface Geophysical Surveys) - A VLF survey in combination with the fracture trace analysis will help define lineaments for monitoring well installations. Seismic refraction will be used to help define gross changes in lithology (e.g. unconsolidated materials to bedrock interface) in the valley. Task 3.11 (Drilling, Sti-atigraphic Characterization, Subsurface Sampling, and Well Installation) Work will include drilling and collecting subsurface samples. Sampling activities performed in this task will help identify the likely source(s) of contamination as well as the extent of the contamination. Samples will be analyzed for VOCs, SVOCs, and metals by a CLP laboratory. Task 3.12 (Downhole Geophysical Logging) - Work in this task will help identify the overburden and bedrock geology, bedrock fractures, and significant water bearing zones. Task 3.13 (Surface Water & Sediment Sampling) - Sampling in this task will help identify the f 39 300087 m Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WA# 037-RI-C0-02 P areas(s) of contamination, and magnitude of impacts to receiving streams. Samples will be collected during latter part of the drilling task, after PSA specific analytical data have been generated and preliminary reviewed. This will optimize surface water and sediment sample I collection points. I Task 3.14 (Surveying) - Surveying will be performed using GPS to identify the latitude, longitiide, and elevation of soil sampling locations. Soil boring and well casing elevations will be V measured by a New Jersey-licensed surveyor. Task 3.15 (Quarterly Monitoring and Sampling) - Monitoring of groundwater levels/stream I flows and quarterly sampling of existing wells and surface water will be performed in this task. I Task 3.16 (Landscape Restoration) - Task includes work to restore areas disturbed by drilling, sampling, or testing activities, and disturbed areas around the trailers, staging areas, I decontamination pads, and waste storage areas. Task 3.17 (Demobilization) - At the end of Phase I, personnel, equipment, and supplies will I be demobilized from the site. Task 3.18 (Phase I RI Summary Report) - A 50-page report describing results of the Phase I investigation will be prepared which identifies likely contaminant source areas to be investigated I in Phase O RL i Phase n RI Tasks Task 3.19 (Phase II Work Plans) - The Work Plan and FOP will be revised to reflect die scope I of work to be performed in the Phase II RI. To the extent practicable, information from the Phase I I FOP will be used to prepare the Phase U FOP. Task 3.20 (Mobilization) - This task will include the mobilization of equipment and supplies I to the site. Task 3.21 (Surface and Downhole Geophysical Investigations) - VLF surveys will be I performed to define fractures zones at PSAs and to identify subsurface well point locations and monitoring well installation locations. Hammer seismic refraction will be used to help define gross changes in lithology (e.g. unconsolidated material to bedrock interface) in the valley. I Downhole geophysical logging will help identify the overburden and bedrock geology, bedrock p fractures, and significant water bearing zones. I 40 300088 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 Task 3.22 (Drilling and Environmental Sampling) - Site-specific soil, groundwater, soil gas, surface water, and sediment samples will be collected to delineate extent of contamination and to gather sufficient data for risk assessments. Task 3.23 (Hydraulic Testing) - Slug injection/withdrawal tests and multi-well constant-rate aquifer pumping tests in both overburden and bedrock wells will be performed to characterize aquifer properties. Hydraulic testing will be performed in Phase II following the evaluation of data generated during Phase I to ensure that the proposed locations provide appropriate data for use in the Feasibility Study and groundwater modeling efforts. Where appropriate, hydraulic testing may be initiated during Phase I, Task 3.24 (Dye Tracer Studies) - Will be conducted with the hydraulic tests to characterize the aquifer properties and travel velocities. Task 3.25 (Ecological Sampling) - The scope and need for ecological sampling will be determined following completion of ecological risk assessment. Task 3.26 (Surveying), Task 3.25 (Landscape Restoration), Task 3.26 (Demobilization) - Will be performed as described in Phase I RI. P TECHNICAL SCOPE OF SERVICES The tasks for the Pohatcong Valley Groundwater Contamination Site Remedial Investigation and Feasibility Stijdy (RI/FS) are as follows: Task 1 Project Planning and Support Task 2 Community Relations Task 3 Phase I and Phase n Field Investigations Task 4 Sample Analysis Task 5 Analytical Support and Data Evaluation Task 6 Data Evaluation Task 7 Assessment of Risks Task 8 Treatability Stiidy/Pilot Testing Task 9 Remedial Investigation Report Task 10 Remedial Alternatives Screening Task 11 Remedial Alternatives Evaluation Task 12 FS Report and RI/FS Report 41 300089 I s Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAif 037-RI-C0-02 Task 13 Post RI/FS Support o Task 14 Negotiation Support I ° Task 15 Administrative Record I «> Task 16 Work Assignment Closeout The tasks identified above will be completed according to the schedule presented in Section I 1.4 of this document. I Described below is the work that has been initiated and which will be performed for this project. The work activities described in the following sections are based on EPA's 27 August 1997 SOW, ICF Kaiser's 23 December 1997 Draft Work Plan, and EPA's August 1998 Comments I on the Draft Work Plan, as amended by EPA's 2 February 1999 comment letter. I TASKl PROJECT PLANNING AND SUPPORT I 1.1 Project Management Project Management will be performed to track project schedule and budget, to communicate with USGS and EPA, schedule personnel, prepare cost estimates for required work, and prepare p monthly invoices. Project Management will be performed throughout the course of the RI/FS. I 1.2 Access Agreements I Any sampling, drilling, geophysical, or other RI activities performed on private or public property will require written approval from the landowner. The Contiractor will support EPA's I efforts to gain access to sites where work is proposed. Two types of access agreements will be needed for this project. Type 1, the simplest 1 agreement covers sampling of domestic wells. Type 2 includes those sites where investigatory work such as soil gas studies, existing monitoring well sampling, drilling, and/or monitoring well I installation will be performed. Access agreement packages have been mailed to over 120 homeowners, businesses, and the I PSAs where some type of sampling will be performed. The access agreement packages included information brcxhures, questionnaires regarding well characteristics, and access agreements to be signed and returned to EPA. Approximately 66 follow-up access agreements letters have been I mailed to property owners who did not sign the original access agreement. To track the status of 9 the access agreements, a Site Access Database has been developed and maintained. I 42 300090 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 Although EPA is performing most tasks associated with obtaining access agreements, in Task 12 the Contractor may be tasked to assist EPA in the preparation and distribution of access P agreement packages to property owners who did not receive the original access agreement package or follow-up letter, or who have not responded to EPA. This taskmay also require the I Contractor verify property owner addresses and maintain the Site Access Database for the tracking of access agreements as required by EPA. I 13 Project Organization, Schedule and Costs I 1.3.1 Project Organization I The Contractor shall designate a Project manager (PM) as their primary point of contact for this work assignment. I 1.3.2 Initial Site Inspection I The Contractor shall coordinate with the EPA WAM within five days after issuance of this I work assignment to conduct a initial site inspection of the site. The site inspection should be completed prior to the scoping meeting to be held for the purposes of responding to Contractor questions concerning the site, statement of work and or schedule of the work. 1.3.3 Scoping Meeting I The scoping meeting should be scheduled at the same time as the site inspection allowing sufficient time to evaluate the initial site visit. Because die Work Plan for this RI/FS has been I approved by EPA Region 2 and has been incorporated wholly as the SOW for this Work Assignment, no modifications shall be made to the Statement of Work until such time as such I changes are agreed to by the WAM at the Scoping Meeting, I 1.3.4 Work Plan Submittal I Within 30 days after the scoping meeting die Contractor shall furnish (3) copies of die work plan accompanied by a detailed cost estimate prepared at the sub task level. The Contractor shall utilize the guidance and technical direction contained herein to prepare this work plan. The I Contractor shall be advised that the detailed contents content of this work plan has previously been approved by the technical staff in Region 2. The Contractor's work plan should only modify those sections necessary to fit the Contractor's organization. For example, if the previous I contractor (ICF Kaiser) proposed to accomplish a task with subcontract labor and die Contractor would prefer to utilize their own staff, the Contractor should specify and highlight diis deviation. All such proposed deviations shall be negotiated at the scoping meeting. 4 43 300091 I I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 TASK 2 - COMMUNITY RELATIONS The Contractor will provide community relations support during the RI/FS in the Pohatcong Valley area. EPA's reappearance in the community during field work, after a long period of inactivity in the area, is likely to generate community interest in remedial activities. Newcomers to the area, in particular, may not be aware of the Pohatcong Site or the limits of the Well Restriction Area, and they may have concerns about the quality of their well water. Further, community outreach efforts will be complicated by the size of the site, which encompasses a long valley and three different municipalities. The objective of this tiask is to implement a community relations program for the Pohatcong Site that encourages two-way communication between EPA and the local public. Implementation of community relations activities will enable EPA and others contributing to remedial response efforts to: provide the public the opportunity to express comments on and provide input to technical decisions; inform the public of planned or ongoing actions; and identify and resolve conflicts. Furthermore, an ongoing, well-implemented community relations effort will allow EPA to interact with the community and local officials on issues regarding water quality and extent of cleanup. The community relations program will be integrated with all technical activities p undertaken at the Pohatcong Site. All work oudined in this task will be performed at the direction of the designated WAM and in coordination with the designated Community Relations Coordinator (CRC). All community relations activities will comply with the statutory requirements as defined in the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA). In addition, community relations activities will be consistent with the latest relevant Superfund policy and the guidance in Community Relations in Superfund: A Handbook (January 1992, EPA/540/G-88/002). 2.1 Project Implementation 2.2 Public Meeting/Public Availability Session Support The Contractor will assist EPA in preparing for two public meetings. The public meetings may be held as "public availability sessions," which are less formal than public meetings. The Contractor will assist with a public meeting "which will present the findings of the RI/FS, describe EPA's proposed remedy, and to elicit and respond to public comment." However, since this public meeting, which is often referred to the "Proposed Plan Public Meeting," is a post-RI activity, it has been included in Task 10. p For each public meeting/public availability session, the following support will be provided: 44 I 300092 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 ° Identify, recommend, and reserve a meeting site; ° Provide logistical support (e.g., audio-visual equipment rental and delivery, room fees); o Attend a strategy meeting or participate in a conference call prior to the meeting; ° Prepare an agenda, sign-in sheets, and tent cards; ° Prepare audio-visual materials, which for estimating purposes may be either 20 overhead transparencies or one multi-media projector presentation with 20 images, and two presentation boards; ° Assist during a dry run; ° Reproduce and distribute handouts; ° Attend and record the meeting and prepare a draft and final meeting summary; and ° , Forward a copy of the final meeting summary to EPA and to the information repositories. 23 Fact Sheet Preparation This task requires die Contractor to prepare up to two draft and final fact sheets. The fact sheets will parallel "milestones" or significant events achieved at the Pohatcong Site. The Contractor will research, write, edit, lay out, reproduce, and mail two fact sheets to approximately 500 people on the site mailing list. The Contractor will modify existing graphics to create three, simple, site-related maps or schematics that will be used in the fact sheets. Fact sheet specifications: black ink on recycled 11 X 17 inch paper, folded. EPA may select paper color from samples. For each fact sheet, the Contractor will submit a draft fact sheet for EPA's review. Following receipt of EPA's comments, the Contractor will submit a final fact sheet to the WAM prior to reproduction and distribution of the fact sheet to people on the mailing list and to the information repositories. 2.4 Develop an Internet Site (THIS SECTION IS PURPOSELY DELETED) ^m 45 300093 I p Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 2.5 Prepare Public Notices The Contractor shall anticipate publishing a public notice in local newspapers serving the site community prior to each public meeting. Therefore, a total of two draft and final public notices are anticipated for this Task. The public notices will be placed in widely read local newspapers, such as the Star-Ledger and the Star Gazette. 2.6 Prepare and Update a Site Mailing List The Contractor will prepare a mailing list diat encompasses the following: addresses from EPA's original 1990 mailing list; updated information about federal, state, county, and local officials; and addresses of residential and commercial/industrial well owners identified in this Work Plan. The Contractor will update the mailing list following public meetings, elections, and periodically as needed. The Contractor will provide copies of the list to the WAM upon request, with a minimum of one initial copy for EPA's file. For budgetary purposes, the Contractor shall assume that the mailing list will contain 500 names and addresses. TASK 3 FIELD INVESTIGATIONS As described in Section 0.6.7 of this SOW, field investigations will be conducted in two phases. The first phase will include valley-wide data collection and screening of PSAs. The second phase of the RI will focus on detailed investigations of a few specific PSAs and ecological receptors which are considered to be the most likely sources of contaminants. The field tasks are described below in the approximate chronological order in which they will be performed. The tasks are grouped into Phase I and Phase II. p Prior to any sampling, drilling, geophysical, or other RI activities performed on private or public property, written approval from the landowner in the form of an access agreement will be 46 300094 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 obtained. 4 PHASE I RI 3.1 Collection and Evaluation of Existing Data A large amount of geologic, hydrogeologic, and water quality data have already been collected for the Pohatcong Valley area, including database searches for existing municipal, industrial, residential, agricultural, and environmental monitoring wells in the area; collection of existing geologic maps for the area; discussions with the U.S. Geological Survey (USGS) and the New Jersey Geological Survey (NJGS); and the collection of several existing Environmental Cleanup Responsibility Act (ECRA), Industiial Site Recovery Act (ISRA) reports, and one RI report that pertain to the potential source areas (PSAs). Based on conversations held with the USGS, NJDEP, SCS, and the New Jersey American Water Company, there are several other geologic- and hydrogeologic-related reports available for review. Therefore, the goals of this task are: To collect additional data that will improve the existing geologic database and assist in the preparation of preliminary geologic cross-sections, glacial overburden thickness maps, a preliminary top-of-bedrock elevation map, and assist in the identification of specific areas or depth intervals in the valley where sorted outwash sand and gravels might provide preferred pathways for contaminant migration. These maps and cross sections will all be revised and updated as new drilling information is obtained during the RI, To collect additional data that might be available concerning well yields, hydraulic conductivity, or transmissivity of the geologic materials. In particular, existing pumping test data will be collected and evaluated to gain a preliminary estimate of the hydraulic properties of the bedrock and glacial overburden materials. To collect information on existing wells in the valley used for irrigation, if any, including the well locations, average pumping rates, methods of water application, and uses of the water. To collect and evaluate the historical data for wells, such as the Vannatta Street well, to determine if contaminant concentrations are decreasing over time and how fast; To collect precipitation and other climatic data for the period of investigation, which will be needed to estimate evapotranspiration rates and groundwater recharge rates (input parameters for the groundwater model); To collect flow data, water quality data, and sediment chennistry data for Pohatcong Creek, if available, in order to develop a preliminary characterization of 47 300095 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 b the Stream. The USGS has a monitoring station on Pohatcong Creek at New Village, which is about 2 miles downstream of the study area. Water quality data were collected at this location from 1979 to the present. In addition, studies conducted by the USGS in the Delaware River estuary and New Jersey tributaries in the early 1980s may have generated other useful data concerning water quality or sediment chemistry of Pohatcong Creek; and ° To evaluate the Warren County soils report from the U.S. Department of Agriculture (USDA) to determine if soil maps can be used to indicate where fine- or coarse-grained glacial deposits underlie the surface, to determine where residual soils from weathered gneiss might indicate gneiss at shallow depth, and to identify any mapped soils that are poorly drained or wet most of the year which might indicate groundwater discharge areas^ These data will be used to assist the selection of drilling and monitoring activities, to create preliminary geologic and hydrogeologic maps, to further characterize the geologic materials in the study area, and to provide data for the groundwater modeling effort. Collection and evaluation of existing data will be performed over a two-week period and will be thorough, but not exhaustive. A search of computerized bibliographic databases will be performed, and references will be obtained if they appear to be relevant. In November 1997 and in early 1998, the NJDEP collected and analyzed groundwater samples from approximately 30 residential wells in the study area; the data from this sampling m event will be evaluated and compared to data from the 1984/1985 NJDEP/WCHD well sampling data, : ;; 3.2 Fract'ufe'e Trace Analysis This task has been completed. Fracture trace analysis is a groundwater investigative tool that was developed nearly 30 years ago, Lineations detected on aerial photographs are underlain by relatively narrow zones (e.g., 20 to 100 feet wide) of fracture concentration (Lattman, 1958; Lattman and Nickelsen, 1958). Fracture traces and lineaments can be detected as subtle or obvious linear features or shading anomalies on black-and-white, color, and false-color infrared photographs. Stereo-paired photographs and a stereoscope make identification of fracture traces much easier. A considerable number of studies have been conducted to establish the nature and significance of fracture traces and to determine the importance of fractiire zones to rock permeability, well yields, and groundwater flow systems (Lattman and Parizek, 1964; Parizek, 1976; Siddiqui and Parizek, 1971; and Mundi, 1971). Hydraulic conductivities of these fracture zones have generally been shown to be 5 to 100 times greater than adjacent rock of the same lithology. The greatest hydraulic conductivities can be found at the intersection of two or more fracture traces. The movement of groundwater (flow rate and flow directions) in the bedrock will be controlled primarily by joints, fracture zones, and solution cavities. Hence, defining the magnitude and orientation of fractiiring and solution features in the valley will be a necessary part of the RI. Strategically important lineament locations will be investigated during the surface w^ geophysical investigations (SubTask 3.10), drilling activities (SubTask 3.11), Downhole geophysical logging (SubTask 3.12) pumping test analysis (SubTask 3.23), and dye tracer tests •^^ 300096 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-O2 (SubTask 3.24). 4 A fracture trace analysis has been performed to identify bedrock fracture systems in the area (ICF Kaiser, 1998). The Fracture Trace Analysis Report prepared in June 1998 identified the following: Fracture traces were identified on every photograph that was studied. Qualitatively, fracture traces were more readily visible on die valley walls and ridgetops, where Precambrian metamorphic rocks are at the ground surface. Fracture traces were less frequently detected on the valley floor, where the Paleozoic limestone and dolomite bedrock is buried beneath 0 to 130 feet of glacial overburden. A large percentage of the fracture traces appear to be oriented northwest-southeast (perpendicular to the valley) and northeast-southwest (parallel to the valley axis). This would agree with structural geologic theory where fractures should be oriented parallel to the major and minor axes of stress imposed on the area during structural deformation. Some of the fracture traces could be markers of strike-slip faults and some could be lying along thmst faults or minor splay faults in the rock. The fracture traces detected on the valley floor could indicate vertical faulting in the bedrock or a combination of faulting and enhanced solutioning of the carbonate rocks resulting in linear karst features. P Short fracture traces were detected in the center of the valley, even where glacial overburden is presumably greater than 50 feet thick. Fracture traces in these areas are probably not due to fracturing alone, but are due to solutioning along fractures and faults at depth. No fracture trace i was identified which extended across the entire valley (cross-valley lineament). B 33 Cultural! Resources Investigation A Phase LA "Reconnaissance Level" Cultural Resources Study will establish the presence or absence of documented cultural resources in and near the study area. The Phase lA Cultural Resource Study will adhere to the requirements of the CERCLA/SARA Review Manual (EPA, January 1988). The general location of each documented resource will be determined, and preliminary recommendation about the potential eligibility of each resource to die State and National Registers of Historic Places will be developed. A report of this study will be written and submitted to the Contractor for inclusion in the RI report. 0 The study will attempt to define and describe the Area(s) of Potential Effect. The study will include the following, at a minimum: 49 300097 i I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 ® Background and historical research -.various repositories will be visited in order to collect information on the historical and prehistorical background of the study area. The repositories providing data include: State Historic Preservation I Office (SHPO), State Museum, University Libraries, local historical societies, and the Cultural and Heritage Commissions to: I - Gather and review historical documentation and historic maps; - Gather and review other cultural resource studies completed in the area; I - Gather and review relevant information from historic site files at SHPO; - Interview knowledgeable local persons; I - Review relevant environmental and soils data; and o - Review Land-Use Sensitivity Study. Field inspection by I professional archaeologist and/or architectural historian. i» Analysis of gathered data, I ® Report of findings and recommendation (as per current SHPO standards and requirements), I e Photographs to illustrate text » Project site map to illustrate text p » Bibliographic references The report may contain specific recommendations for further investigation and methods to I protect and avoid significant resources. f 3.4 Subcontract Procurement It is anticipated by EPA that subcontractors may be required to perform the various elements I of the field investigations. In its Work Plan, the Contractor may consider the use of I subcontractors for the performance of the following activities: Surface Geophysical Surveys: Very Low Frequency (VLF) Electromagnetic t Surveys and/or Hammer Seismic Refraction Surveys I Downhole Geophysical Logging of Uncased Boreholes; Identification of Subsurface Utilities prior to intmsive activities at the site; Soil Gas Surveys, using a Geoprobe unit to obtain soil gas samples and a field I gas chromatograph to analyze the samples; Drilling Activities, which includes equipment for drilling and sampling p shallow boreholes, drilling and sampling deep boreholes, the installation and 50 I 300098 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-O2 development of monitoring wells, and the performance of packer tests; P «> Physical and chemical analyses of samples (fixed-based laboratory) for B geotechnical and remedial feasibility evaluations; • ^ Surveying, to determine the elevation of sampling points and monitoring wells; ^ ° Pickup and disposal of investigation-derived wastes (DDW); • ° Cultural resources survey to identify whether prehistoric or historic artifacts « are present at the site; ft ° Surveys of sites to determine the presence or absence of the bog turtle or dwarf wedgemussel; and fi " Landscaping services to repair the macadam and concrete at drilling locations and to replace sod and topsoil where tire ruts from heavy equipment have ^ developed, p In addition, rental agreements/procurement will be necessary for the rental and installation of M the field trailers, installation of electrical hookups, installation of sanitation facilities, telephone insftallation, and non-IDW garbage collection. EPA is currently negotiating the site of the command center during intrusive investigations. I Bid specifications will be developed and finalized under Task 3.04, and the bidding process and awarding of contracts will also be performed as part of this SubTask. 3 J Delineation of Wetlands I BH Wetlands identification and delineations will be conducted to identify sensitive ecological habitats in areas scheduled for geophysical surveys, drilling, or other investigation activities. Plate 16 presents the approximate extent of wetland areas in the PVGCS using the U.S. Department of the Interior National Wetland Inventory (NWI) maps. This figure also presents the PSA names and locations which are in the immediate vicinity of the wetland areas. I Based on the proximity of the PSAs to the wetlands identified on the NWI maps, EPA ^ assumes that approximately 15 PSA locations will require that a wetlands delineation be M performed. Wetland delineations performed will follow die procedures outlined in the U.S. Army Corps of Engineers (1989) "Federal Manual for Identifying and Delineating Jurisdictional ^ Wetlands," and will use the three character approach of hydric soils, vegetation, and hydrology. I As part of the assessment of the vegetation, upland and hydric plants in a potentially-affected area will be identified. If dominant plant species cannot be identified in the field, they will be sampled and sent to a laboratory for identification. Identified wedands will be classified according to i protocols described in New Jersey's Freshwater Wedand Protection Act (NJAC 7:7,), Following die delineation of wetlands in the field, wedand verification applications will be P m 51 300099 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 prepared in accordance with NJAC 7:7A-8,3 and submitted to the NJDEP, In accordance with NJDEP regulations, a wedands map will be generated for each field- delineated wetland mapped at the site. Field work at the 15 PSA locations suspected of containing wedands will not be performed until weUand surveys and field delineation activities have been performed. In addition to wetlands maps, 100- and 500-year floodplain maps will be generated for the entire project area, using the National Flood Insurance Program's Flood Insurance Rate Maps. The maps will describe the floodplain boundaries, contaminant source areas, and other areas that would be potentially affected by remedial activities. The floodplain delineation will take place during the RI, and an assessment performed during die FS, 3.6 Survey of Endangered Species Habitat EPA has identified that two listed species may be present in the study area: the federally endangered dwarf wedgemussel (Alasmidonta heteroton) and the bog turtle (Clemnys muhlenberghii). In order to ensure that impacts to these two listed species are minimized, a qualified biologist will survey proposed work zones within the study area for these species, as specified below. The dwarf wedgemussel lives in creeks and rivers with slow to moderate flow having sand, p muddy sand or gravel bottoms. They have been identified within three miles of the study area. The bog turtle lives in emergent and shrub/scrub wedands ecosystems. It has been identified within two miles of the study area, and may be present in the study area. In order to ensure that no proposed work will result in potential adverse impacts to bog turtle habitat or dwarf wedgemussel, a survey of potential habitats will be conducted at the PSAs identified on Plate 16. Should other PSA contain suitable habitat for these species, up to four additional surveys will be conducted. Reports detailing all surveys will be submitted to EPA for review and approval prior to the initiation of field activities in sensitive habitat areas. If the survey(s) positively identify(ies) the presence of these species in proposed work areas, or in areas potentially impacted by the proposed work, the Conductor will relocate sampling points following consultation with EPA to prevent planned activities from impacting either species. 3.7 Mobilization A centralized location will be chosen in the Washington, New Jersey area to serve as a base of I operations for die RI field activities. Arrangements will be made with the landowner for use of the land and permission will be obtained to set up two field trailers, and connect to utilities.. This location must already be enclosed by a security fence and have limited access. In addition, p electric and telephone utility trunk lines must be in close proximity to the site so that hookup is 52 I 300100 Pohatcong Valley Gnsundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-O2 # not prohibitively expensive. The Vannatta Street well property has tentatively been selected as a possible location to set up the field operations headquarters, but this possibility has not been fully evaluated nor confirmed with the landowner. Q One trailer will be set up as a field office and will contain desks, chairs, tables, filing cabinets, Q a telephone, a FAX machine, and at least one computer with Intemet/E-mail capabilities, Basic office activities will be performed in this trailer, A second trailer will be used for storage of equipment, tools, expendable supplies, and other related RI materials. However, this tiiailer will not be used for storage of samples. The trailers will be connected to electrical and telephone utilities, as necessary. Bottled water will need to be provided for drinking purposes. It is assumed that a suitable parking area is already available at the site, so that no road or parking lot will need to be constructed. Portable sanitary facilities will also be set up, if necessary, on the B premises. The Contractor and its subcontractors will mobilize to the site all personnel, tools, equipment, and supplies necessary to perform the work specified in Task 3 (Field Investigations). 0 A second area will be chosen and arrangements will be made for the temporary storage of water tanks, drums, drill core boxes, and IDW materials. These materials will be temporarily stored until such time as they can be sampled, analyzed, and a decision can be made concerning „ their final disposal. Disposal of these solid and liquid wastes are discussed in Task 12 "Disposal of RI/FS Generated Waste". The temporary storage area will be enclosed by a security fence and access to the area will be stricdy limited. The Washington Township POTW property has tentatively been identified as a possibility for temporary IDW storage and staging area. P During mobilization activities, the Contractor will perform walkthrough inspections of the sites identified on Table 3-6 and inspect and generate field sampling maps for approximately 11 additional PSAs where adequate site maps are not available. Prior to the inspections, site access r-, will be obtained under Task 1.2 Work to be conducted in this task also includes conducting spot I checks along sections of the abandoned Morris Canal. The purpose of these inspections is to identify whether the sites identified in Table 3-6 or the abandoned Morris Canal are potential p-v sources of contamination. Field personnel will take detailed notes describing findings of the i j inspections. The Contractor will report the finding back to EPA and modify the Hierarchical List of PSA Sites accordingly. p 3.8 Soil Gas Investigations D A soil gas survey can be a quick, relatively inexpensive, and effective means for identifying potential VOC contamination in soil from current or previous activities at a given location. The effectiveness and ability of a soil gas survey to estimate subsurface contamination is highly D dependent on site-specific conditions (such as hydrogeology, soils, and climate) and contaminant properties, including concenti:ation, solubility, vapor pressure, and partitioning coefficients. Soil gas above a contaminated aquifer may not contain detectable levels of contaminants due to the 0 variability of factors such as contaminant concentration in groundwater, the depth of the water table, and soil type. Soil gas surveys are least effective where barriers to gaseous flow and diffusion exist, as in soils with low permeability (e.g. clayey soils) and in water-saturated soils. 53 300101 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 i Temperature and rainfall also affect contaminant concentrations in soil gas. The soil gas survey at Pohatcong Valley will be perfonned in dry weather when subsurface soils are relatively dry. A total of 58 PSAs have been identified for investigation. In order to screen these large number of sites for the presence of VOCs in the subsurface, soil gas surveys will be conducted. At each of the 58 PSAs, soil gas samples will be collected at three locations from a depth of about 5 feet, and will be analyzed for VOCs in a mobile laboratory using a gas chromatograph (GC) and fl approved EPA analytical methods. PSAs will be investigated in the hierarchical order identified in the hierarchical list provided in Appendix B, The soil gas samples will be collected by driving a hollow steel rod into the ground to a depdi of approximately 5 feet and the rod will be retracted a few inches, thereby exposing a short length of steel mesh screen. The screened section is attached to tygon tubing which leads up to the ground surface. By placing a vacuum on the tube using a peristaltic pump and a vacuum box, a soil gas sample is collected into a Tedlar bag and delivered to the on-site GC for analysis. At each PSA, the soil gas sampling locations will be chosen in the vicinity of former or active above-ground storage tanks (ASTs) and underground storage tanks (USTs) that store or did store chlorinated solvents, stained soil areas, sump areas, or other locations that are likely places for contaminant entry into the subsurface. Many of these locations will be paved with asphalt and concrete. At these locations, the pavement will be chiseled away in order to collect the samples. Once sampling is complete, the steel rod will be withdrawn and the hole will be filled with % powdered bentonite. Where pavement was disturbed, the surface pavement will be patched with like material. Prior to drilling at the PSA, a utility markout will be performed to prevent damaging underground utilities. The results of the soil gas investigations will provide information regarding the presence of VOCs in subsurface soils, and will assist in the identification of likely source(s) of VOCs. Information obtained during the soil gas sampling in combination widi data collected during the sampling of existing wells (sub task 3.9), will be used to revise the Hierarchical List of PSAs, to determine if additional sampling at each PSA is warranted, and to select additional drilling and sampling locations to gather maximum information regarding the PSA. Analytical data generated during the soil gas investigations will be evaluated in Task 6 (Data Evaluation). 0 3.9 Sampling Existing Wells There are over 300 existing domestic, industiial, and environmental monitoring wells located 0 within or adjacent to die study area (see Plates 6 through 11, and Tables 4-1 dirough 4-6). The Warren County Health Department sampled 117 wells in the valley in 1984 and 1985 to determine die extent of VOC contamination. Most of the wells have not been sampled since 1985. In addition, a large number of new wells have been constructed in the area since the 1985 water quality survey. These wells are located outside of NJDEP's well restriction area, with some screened in die limestone bedrock, some screened in weathered gneiss, and some in the glacial overburden. EPA has selected existing wells for sampling which are distributed across the 54 300102 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 PVGCS. The Fracture Trace Analysis Report was reviewed to assist in selecting the wells. 4 In the early part of the RI, approximately 110 of the existing wells will be sampled and groundwater elevations measured in order to assist in: o defining the current nature and extent of contamination in the valley; ° locating new drilling and sampling locations for SubTask 3,11; o identifying the most likely areas of contaminant sources; and ° refining the Hierarchical List of Sites present in Appendix B. Access agreements will be obtained before sampling occurs (Task 1). Plate 17 presents the locations of existing residential, monitoring, and production wells that the Contractor shall propose to sample under diis SubTask. The identity of the wells tentatively chosen for sampling are listed in Table 4-7. These wells have been chosen for the following reasons: o They are distributed throughout the valley and will help define the lateral extent of contamination; ° They are representative of both the bedrock and the overburden in order to help define the vertical distribution of contamination, and vertical hydraulic gradients; 4 ° Many of them are wells that were sampled in 1984-1985, in order to evaluate M changes in water quality that has occurred over the past 15 years; ® ° They do not have large screened intervals, so that contamination, if detected in @ a well, can be assigned to a specific depth interval; P o They are located at PSAs, if possible, in order to help assess whether a PSA can be eliminated from further consideration as a source area. A large number of B the existing wells to be sampled will be monitoring wells at PSA sites. ™ With the exception of samples collected from residences, the 110 samples collected from ® existing wells will be analyzed for VOCs, SVOCs, and metals by EPA's CLP. Samples collected ^^ fix)m residenceswil l be analyzed by EPA's Region 2 laboratory. Having water quality data from H a specific set of wells tested in 1984-1985 and again in 1998 will allow the Contractor to evaluate whether major changes in water quality have occurted over time. g. For residential and municipal wells, samples will be collected as closely to the wellhead as _. possible but not direcdy from the well. In no case will the well be opened. In most cases, the 11 samples will have to be collected from a faucet. If water-supply wells are actively used and are regularly drawing water out of the wells, these wells do not need to be extensively purged prior to sampling. If water is sampled from a faucet, then the faucet will be allowed to mn for 15 minutes prior to sampling in order to clear water out of the plumbing and obtain a fresh sample. 55 300103 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 p However, in no case will a sample be collected if the water has passed through a water softener, a carbon filter, or other water treatment device that would significanUy alter the water quality. For each sample collected, specific conductance, turbidity. Eh, dissolved oxygen, temperature, and pH will be measured. For existing monitoring wells, the wells must first be purged prior to sampling. Low-flow purging (<0.5 L/minute) will be performed in each well, using a pump positioned at the depth of the most permeable zone in the screened interval (or near the middle part of the screen if this zone cannot be determined from existing information), until pH, temperature, dissolved oxygen, and specific conductance do not change by more dian 3% and turbidity does not change by more than 10% between successive readings taken 10 minutes apart (Puis and Barcelona, 1996). The depth to water before and during low-flow well purging will be measured to ensure that drawdown is minimized. Samples will be collected from the pump discharge as soon as purging is completed. 3.10 Surface Geophysical Investigations VLF Survevs ^^^ VLF surveys will be performed in approximately six areas during Phase I. These surveys will be conducted where: 1) existing well sampling or subsurface sampling indicate that a contaminant source maybe present; 2) two or more fracture traces were identified; or 3) unexpected hydraulic heads or contaminant distributions indicate that preferred flow pathways might exist in the bedrock aquifer. These surveys will be performed in accordance with USEPA PS guidance, "Surface Characterization and Monitoring Techniques" (EPAy625/R-93/003a). In particular, changes in ground surface elevation and depth to bedrock will be accounted for during interpretation of the survey data. The results of the VLF surveys will be compared to the locations of fracture traces identified from aerial photos to determine if there is concurrence between the two methods. The selection of borehole drilling and monitoring well installations will be governed to the extent practicable, by the results of these surveys. The goal is to perform as much of the subsurface monitoring and sampling as possible from within fracture zones that are preferred pathways. The VLF surveying method will require that a grid be established over the survey area. Field personnel will walk along each of the grid lines, taking measurements at 10-ft intervals. The readings are stored in the field instrument's memory and later downloaded to a computer for further data processing. Conductive bodies such as buried metal debris and water or clay filled fractures can be detected at depths up to approximately 80 feet with this method. The primary purpose of conducting VLF surveys will be to identify fracture zones in the bedrock that might be enhancing subsurface contaminant migration. 56 300104 Pohatcong Valley Gmundwater Contamination Site P\Aay 1999 Statement of Work WAtt 037-RI-CO-02 The theory behind the VLF survey method is that a parallel magnetic field and perpendicular P electrical field (in relation to the Earth's surface) is generated by a VLF transmitter such as those used for military communications. Geophysical anomalies are produced by two different processes. The first, a vortex anomaly, is associated with electrical currents generated within conductive bodies in the subsurface. As a VLF wave travels over the ground surface it is refracted vertically downward. If a subsurface conductive body is encountered, the primary VLF electrical field causes a secondary electrical field to form on the body. This secondary electrical 0 field in turn produces a secondary magnetic field around the body. The secondary magnetic field adds to the primary magnetic field from the VLF transmitter and creates the anomaly. The second type, a galvanic anomaly, is created when the primary electric field flows toward conductive bodies and away from resistive bodies. The resulting disturbances in the current flow are reflected as anomalies in the electric and magnetic fields. Galvanic anomalies must be at least 300 feet in length to channel enough current to produce the anomalous reading. Seismic Refraction Seismic Refraction is preformed in areas where the depth to bedrock is not well known based on well record data and outcrop information. Seismic refraction techniques use an engineering seismograph, a suite of geophones, and a seismic sound source such as a small explosive or a sledge hammer. The geophones are firmly place into the soil at land surface and connected to the seismograph by a seismic cable. Two to five site are selected to hit the ground with the seismic sound source. The sound energy passes through the subsurface at various speeds and travel paths adhering to Snell's Law. The seismic sound is detected at each of the geophone. The recovered data is analyzed and the depth to zones of significandy different seismic velocities are noted. In a glacial fill valley this method is most useful in determining the depth to the top of competent bedrock. The advantage of seismic reflection is that in a short period of time is possible to determine the depth to bedrock without invasive drilling, 3.11 Drilling, Subsmrface Sampling, and W«M Installation This task constitutes the largest portion of the field activities and characterization work for the Pohatcong Valley RI. In the event that each of the PSAs will require investigation following interpretation of the data generated by the soil gas investigations and existing well monitoring, approximately 170 boreholes will be drilled in the Study Area and 20 permanent monitoring wells will be installed during the RI. However, as stated above, EPA assumes that approximately 20 Q PSAs will require further investigation following die soil gas investigations and existing well monitoring. Outside the planned drilling program at PSA, the Contractor may assume that up to 40 boreholes may be drilled to fill data gaps, and that as many ,as 20 of diese may be converted to groundwater monitoring wells. i Drilling, subsurface characterization, and subsurface soil and groundwater sampling will be performed on two different scales. Most of the drilling and sampling will be conducted in order to characterize the nature and extent of contamination in the vicinity of the 58 PSA properties (i.e., at a localized scale). Approximately 70 shallow (< 30 feet deep; overburden) and 60 deep boreholes (>30 feet deep; overburden/bedrock interface) will be drilled during the PSA investigations. Shallow soil and groundwater samples will be analyzed to determine, whether 57 300105 ^ Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 contaminants have entered the subsurface from each specific PSA investigated. Contaminants detected in these samples can be directly attributed to die site where they were collected. Groundwater samples will be also collected from the deeper boreholes near the overburden/bedrock interface (using temporary wellpoints) to determine whether contaminants are present in the bedrock aquifer, and whether the contaminants migrated downward from the PSA being investigated or migrated laterally from a different PSA located upgradient. Table 4-8 summarizes the number and type of environmental samples proposed to be collected at each PSA. In order to evaluate geology, hydrogeologic conditions, and contaminant distributions on a regional basis (i.e., the Study Area), 40 additional borings will be drilled and 20 of these will be converted to permanent monitoring wells. These borings and wells will be placed in locations generally downgradient or upgradient of die PSAs where data are currendy lacking. Another purpose of these borings and wells is to characterize background (i.e., upgradient) groundwater quality and to better define the downgradient extent of contamination. Drilling and subsurface groundwater and soil sampling will be performed at those PSAs selected from the Hierarchical List of Sites, The Hierarchical List of Sites will be refined following the evaluation of data generated . n Drilling Technique Pohatcong Valley contains up to about 150 feet of glacial sediments overlying fractured limestone and dolomite. The glacial overburden is generally very hard and compact till, and often contains boulders and cobbles. In some zones, clean, sorted sand lenses (glacial outwash perhaps) can be encountered. If diese are saturated with groundwater, they can present a problem to drilling and sampling (known as flowing sands). There is a wide variety of drilling and subsurface sampling techniques available that have different attributes, including drilling speed, ease of sampling, generation of IDW, and associated costs. Prior evaluations revealed potential drilling conditions along with sampling needs and indicated that Rotasonic drilling technology be used for the majority of the drilling and subsurface sampling activities. The Geoprobe technique is recommended for the shallow soil gas sampling to be conducted earlier in the field investigations. This subsection presents the advantages and disadvantages of numerous drilling/sampling technologies and presents arguments for selecting Rotasonic drill rigs to perform the subsurface drilling. Hollow-Stem Auger Hollow-stem augers are proposed for use in drilling boreholes within the glacial and alluvial sediments (i.e., those not penetrating the bedrock). The inside diameter of hollow-stem augers can range from as small as 2.5 inches to as large as 12,5 inches. Hollow-stem augers are particularly useful in drilling through materials which include cobbles and small boulders. The m augers are designed to push cobbles and smaller boulders off to the side of the augers rather than 58 300106 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 drill through them. However, the carbide teeth of the auger bits can grind through soft boulders if 4 necessary. Hollow-stem augers are relatively efficient and the drill cuttings are generally easy to handle. Larger drill rigs will have sufficient torque to turn and advance the augers through most of the known geologic materials in the Study Area, Larger hollow-stem augers (e.g., 6.25-inch inside diameter) would be used to install 2-inch diameter monitoring wells. Smaller diameter hollow-stem augers can be used to collect split-spoon soil samples and collect groundwater samples from temporary well points. The sampling devices all have approximately 2-inch outside diameters and can easily fit inside a 3.25-inch inside diameter hollow-stem auger. Unlike some other drilling techniques, the sampling devices can be lowered down inside of the augers direcdy to the desired sampling interval without removing the drill bit or drill rods. Narrower inside hollow-stem augers will also produce less drill cuttings (i.e., investigation derived waste). A limitation of hollow-stem augers is the uncertainty as to the cause of auger refusal. For example, refusal could be caused by a large boulder, which could be misinterpreted as the top of the bedrock. Mud Rotary The mud rotary drilling technique utilizes a bentonite mud to circulate drill cuttings back to the ground surface (and the cuttings drop to the bottom of the mud bin outside of the borehole and are caught in a series of baffles near the drill rig). The bentonite mud also keeps the borehole open during drilling. The greatest advantage to the mud rotary method is that it can penetrate much deeper than hollow-stem augers, should this be required. The mud rotary technique can be paired with hollow-stem augers to advance a borehole beyond the limit of the augers, ICF Kaiser proposed to use mud rotary drilling techniques to advance boreholes when hollow-stem augers are unable to penetrate deeper and the risk of fluid loss within the borehole is minimal. Mud rotary is a less efficient drilling technique for this study area. There is time spent up front to mix drilling mud, the drilling mud increases the amount of investigation derived waste generated, the drill bit must be pulled out of the hole prior to sampling. It is difficult, if possible at all, to determine when the borehole has advanced into the water table, and the drill bit generally has to go through cobbles and boulders (radier than push them off to the side). Another disadvantage is that significant quantities of drilling mud could enter bedrock cavities, thus plugging the groundwater conduits and making the collection of a representative groundwater sample very difficult. Air Rotary The air rotary drilling technique utilizes a pneumatic drill head that pounds and twists through the soil and rock, using high volumes of fast-nioving air to circulate drill cuttings back to the ground surface. Because the cuttings are not mixed with mud, they are generally easy to handle. 59 300107 i Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 p Collecting soil samples with the air rotary technique is slow and cumbersome (like the mud rotary method). In overburden materials, the drill rig is used to drive steel casing into the soil to keep the borehole open. The drill bit is then used to cut through the soil inside the casing. This I process can also be slow and cumbersome. Once the casing is set into the top of the bedrock, the pneumatic drill bit can drill over 2(X) feet of bedrock in one day. I One particular technique of the air rotary method is called ODEX. This technique uses a special drill bit that allows the casing to be advanced along with the drill bit. The ODEX method I carries a higher per-foot cost but it can save time when advancing through mixed geologic media. I Rotasonic Rotasonic drilling combines rotational and high frequency vibrational forces to advance the I drill bit and drill pipe in the borehole. The primary design difference between Rotasonic drilling and other types of rotary systems is the incorporation of an oscillator, located in the drill head, that produces vibrational energy. The vibrational frequency generated by the oscillator can be I adjusted for different drilling conditions. Rapid drilling rates result from matching the vibrational frequency of the drill pipe, generated by the oscillator, with the resonant frequency of each 10- foot core barrel or drill pipe section. The resulting high amplitude waves within the core barrel or I drill pipe are transmitted to the drill bit. This vibrational energy, combined with the rotational energy, allows effective operation in both unconsolidated and consolidated (or bedrock) material. Rotasonic drilling can be conducted in both consolidated and most unconsolidated units at rates p that equal or exceed other rotary techniques. I Basic equipment associated widi a rotasonic drill rig included the vibratory/oscillatory top- mounted drill head, mast, elevated drilling platform, motor, hydraulic pump and lines, hydraulic drill center, and the drill pipe and core barrels. A rack for holding drill pipe, core barrels and I other drilling materials can be either located on the drilling platform or on a second vehicle. Use of a second vehicle to hold drill pipe allows off-site decontamination of diese material without I moving the drill rig itself. This second vehicle can also be equipped with a tank to store clean drilling water. I The borehole is drilled by advancing two lines of drill pipe. A studded drill bit is attached to the base of die core barrel, which has a 4-inch inner diameter (ID) and 4.5-inch outer diameter I (OD). The core barrel is also available with a 6-inch ID and 6.5-inch OD, or a 3-inch ID and 3.5-inch OD. The core bartel, usually 10 feet in length, is connected to the inner drill pipe and is advanced to the desired depth using high frequency vibration and rotation, forcing a relatively I undisturbed, continuous core into the core barrel. When the core barrel reaches the desired depth, a larger, outer drill pipe, 5.875-, 6.25-, or 8.25-inch OD, is advanced, again using rotation and vibration, along the outside of the core barrel, to die same depth. The larger drill pipe is left in I place to hold open the borehole while the inner drill pipe, core barrel, and sample are retrieved. This assembly is removed from the borehole and lowered towards the drilling platform. The core sample is extruded from the core barrel, using vibration or hydraulic pressure, into a plastic sleeve p that has been fitted to the end of the core barrel. The core sample is completely contained in this 60 I 300108 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 sleeve. The core sample can be alternatively extruded onto a stainless steel tray. A clean core barrel is raised to a vertical position and is returned to the borehole. The process is then repeated, with the core barrel always driven ahead of the outer drill pipe to ensure representative sampling. Successive 4-inch diameter cores are laid end-to-end for lithologic description, screening with a photoionization detector (PDD), and sampling. In this manner, a complete lithologic core from ground surface to the desired depth can be readily obtained. The core sampling procedure can be performed effectively with minimal addition of drilling fluids. Water is added during the advancement of the outer drill pipe, if needed, to flush out cuttings in the annular space between the inner and outer drill pipe or to flush out cuttings at the bottom of the borehole after the sample is retrieved. Excess water produced during these activities is collected in a container located beneath the drilling platform. Soil samples can be collected directly from the 4-inch-diameter rotasonic cores. Volatile organic compound (VOC) samples can be collected from an undisturbed portion of the core immediately after the core is removed from the borehole; this procedure will be discussed later in this section. Samples for less sensitive analytical parameters, such as metals or total organic carbon, will be collected from discrete intervals within the core, depending on the objectives of die specific PSA investigation. The remainder of the core can be crated and stored to provide a physical record of the sample. The rotasonic technique can also be used for groundwater sampling. The inner drill pipe and core bartel are advanced to the bottom of die desired sampling depdi. The outer drill pipe is advanced to the sample depth. The soil is removed using the core bartel, and the outer drill pipe is left in place, A temporary, slotted-screen, well point assembly is attached to the bottom of the P inner drill pipe, A packer is attached to the well point assembly to isolate the sample interval. The well point is lowered to the bottom of die casing. The outer drill pipe is then pulled back to expose the screen. The inner drill pipe is then unscrewed and removed from the borehole. A small-diameter submersible pump is then lowered into the well point, the sample interval is purged in order to reduce suspended solids, and a groundwater samples is then collected. After sampling, the well point assembly is removed, and drilling is resumed. Drilling Technique Comparison All of the drilling techniques have advantages and disadvantages. The inability of the 0 GeoProbe to penetrate cobbly and very dense glacial till has precluded the technique from consideration, except for very shallow depths. The mud rotary technique is capable of penetrating dense unconsolidated materials (glacial till) and bedrock to the depths diat may be required. However, the drilling process is much slower, adding a significant amount of labor involved with the drilling oversight, and very large quantities of investigative-derived wastes are generated. For these reasons, the Contractor may consider not using the mud rotary technique for this investigation. 4 61 300109 I Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 As previously mentioned, the hollow-stem auger technique has several advantages, however, borehole advancement slows considerably with depth (starting at about 50 feet below ground surface) and auger refusal can sometimes occur on top of a boulder, and not bedrock. The ODEX air rotary method can easily penetrate boulders within the glacial till and into the bedrock, however soil sample collection is very time consuming. A combination of hollow-stem auger rig and an ODEX air rotary rig is a worthwhile consideration, however, diis would require significant coordination between the site owners, the Contractor's field personnel, and die drilling contractor. The rotasonic drilling technique is as quick, if not quicker, than the hollow- stem auger technique, and can penetrate through boulders, and into bedrock to confirm the top of rock. The rotasonic drilling technique has one disadvantage not mentioned above; it is sometimes difficult to determine the saturated zone (water table) by just looking at the soil core sample because small amounts of water are used while drilling. The discussion above indicates that a combination of the hollow-stem auger and ODEX air rotary techniques appears to be comparable to the rotasonic drilling technique. ICF Kaiser reviewed the drilling and other related costs in detail to further compare the drilling techniques. The cost comparisons were developed using drilling and other related quotes obtained from contractors capable of providing the levels of service required. Prior costs were based on drilling (by the foot), mobilization/demobilization, oversight labor (ICF Kaiser labor), decontamination, disposal of soil cuttings, disposal of drilling water, collection of soil samples, and collection of groundwater samples. A cost comparison of the hollow-stem auger, ODEX air rotary, and rotasonic techniques for drilling ten 100-foot deep soil borings (and associated sampling) is p presented in Figure 4-1, The total cost using the ODEX air rotary technique is $56,690, the total cost using the hollow-stem auger technique is $53,060, and the total cost for the rotasonic technique is $48,310, The rotasonic cost is about 17 percent lower than the ODEX air rotary cost and about 10 percent lower than the hollow-stem auger cost. This cost comparison suggests that the rotasonic drilling technique may be the most cost effective. Therefore, the Contractor shall assume the rotasonic drilling technology to be suitable for most drilling operations to be performed under this RI. However, the Contractor may also assume that the use of hollow stem augers to be sufficient for the collection of soil and shallow groundwater samples, unless other methods remain more time and cost effective. Methods and Locations of Subsurface Soil Sampling The types of boreholes that will be drilled, the types of soil and groundwater samples that will be collected, and the general nature of the monitoring wells to be installed for this SubTask are described below. A detailed description of each PSA and sampling locations are presented in Figures 4-2 through 4-13 and in Appendix A. p To investigate potential releases from the PSAs, one to two boreholes will be drilled at each of I 62 300110 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WA0 037-RI-C0-02 the PSAs for the collection of soil and groundwater samples. The shallow soil samples will be # collected from the interior of the Rotasonic drill cores. Subsurface soil samples will be collected for analysis based on the following criteria Oisted in preferential order); 1. positive detection of organic vapors; 2. visual identification of discolored soil; and 3. Work Plan- specified depth. Organic vapor monitoring will be performed using an HNu PI-101 (or equivalent) PID. Visual identification will be based on the observations of the Reld Geologist, but can also include any odor characteristics. The Work Plan-specified depth will depend upon the suspected source of contamination at an individual PSA, and, in general, subsurface soil samples are proposed at two and/or ten feet below the ground surface. If the suspected source is essentially at the ground surface (i.e., AST), samples from both two and ten feet would be collected and analyzed. If the suspected source is buried (i.e., UST), one sample from approximately ten feet below ground surface would be collected. Once a soil core has been visually observed and scanned with a PID, and the Field Geologist determines from which depth interval a soil sample will be collected, then a sample aliquot will be collected immediately for VOC analysis. First, the outer soil of the soil core will be scraped away, A small-diameter coring device (e.g., a disposable plastic syringe with the lower end cut off) is then pushed into the soil core in order to collect a nominal 10-g subcore. The sample material is then extruded directly into a pre-tared 60-itiL sample vial that contains 25 mL of analyte-free methanol preservative. The exact procedure for the collection, preservation, and handling of the VOC samples is prescribed by NJDEP (Feb, 1997) guidance, "Methodology for the Field Extraction/Preservation of Soil Samples with Methanol for Volatile Organic Compounds," After the aliquot for VOC analysis has been collected, labeled, and placed in an ice-filled cooler, then subsamples for other parameters will be collected from die same portion of the soil core from which the VOC aliquot was collected. Sampling. Testing, and Response Procedures for the Presence of DNAPLs Since there may be high concentrations of trichloroediene, tetirachloroethene, or other organic compounds in subsurface soils at one or more of the PSAs, procedures will be included in the Field Operations Plan (FOP) diat instinct the Field Geologist on each drill rig to: identify soil horizons where subsurface soils are contaminated with organic compounds, using visual observations (i.e., discolored soil or iridescent sheen), organic odor, on PID readings to identify the contaminated soils; sample and test the soil interval for the presence of dense, non-aqueous phase liquid (DNAPL); determine whether die DNAPL concentration is significant and could migrate vertically downward if drilling was continued; and halt the drilling immediately on the particular boring if there is any potential that DNAPL could migrate downward as a result of the drilling activity. " 63 300111 I 4 Pohatcong Valley Gmundwater Contaminati'on Site May 1999 Statement of Work WAtt 037-RI-CO-02 To assess the presence of DNAPL in a soil core, a grab sample of the core material will be placed in a plastic vial and a small amount of water and a hydrophobic dye will be added. Development of a red color indicates the presence of NAPL in the soil (Cohen and Mercer, 1993), If the DNAPL presence appears to be significant, then the drilling will be halted and moved to a different location to achieve sampling at greater depth. Standard operating procedures for diis testing method and discussion of the criteria to be used for abandoning a borehole will be included in the FOP. Groundwater Sampling From Temporary Wellpoints In boreholes where groundwater is present at a shallow depth, it is assumed that a groundwater sample will be collected at about 15-20 feet below ground surface (ft bgs) using a temporary well point constructed of a continuously wrapped stainless steel (0.010-inch slot) over perforated carbon steel pipe, or a device of similar construction, will be driven in advance of the borehole. Well points have been proposed because the continuously wrapped screen provides the greatest amount of opening for groundwater entry compared to other temporary groundwater sampling devices (e.g., HydroPunch), Shallow groundwater sampling will, in most circumstances, occur at the first water encountered to help determine if there have been contaminant releases from a PSA which have affected shallow groundwater. If the Site Geologist believes that first water encountered to be perched, at his or her discretion, a groundwater sample P will be collected at the next water encountered. To determine when a water bearing zone is reached, soil cores will be cut open and a visual estimation of soil moisture will be made at regular intervals. Once saturated conditions are encountered, drilling will stop, a temporary well screen will be emplaced at the bottom of the hole, and "shallow" groundwater sample will be collected. Once the well point has been removed from the hole, drilling and soil coring will proceed downward. The Field Geologist will routinely record moisture content of the soil core material to determine if the materials are saturated below "first groundwater," or if the shallow groundwater horizon is perched above the true regional water table. The well point will be purged and sampled using low-flow sampling procedures outlined in the corresponding FOP SOP. The well point will be purged of at least three well volumes of water before sampling occiu^. After sampling, multiple depth-to-groundwater measurements will be made in the temporary well point until the water level stabilizes. Immediately after sample collection and groundwater level measurement, the temporary wellpoint will be removed and drilling continued. In no case will the boring remain opened for greater than 48 hours and no disposable sampling devised will be used at shallow sampling intervals after borings are to proceed to bedrock To assess regional groundwater quality, one deep borehole will be drilled at most of the PSAs. In the deep boreholes, a second groundwater sample will be collected just above bedrock using p I 64 300112 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 the temporary wellpoint procedure described above. To accomplish this, the drilling bit will be IP advanced three to five feet into bedrock to ensure that competent bedrock has been encountered, and not just a limestone boulder in the glacial overburden. Due to the anticipation that the highly weathered top-of-bedrock and the lower fraction of the glacial overburden are draining faster than being recharged from above, the Field Geologist will determine if the saturation of the bedrock at this point is sufficient to represent penetration of the water table. When saturated bedrock contact has been established, the temporary well point will be lowered to the bottom of the hole, the drill string will be pulled back 3 feet, and a packer will be inflated between the drill string and the well point. The wellpoint will not be advanced ahead of the borehole. Purging and sampling from the well point can then be performed. An SOP for this procedure is included in the FOP, Depth-to-groundwater will also be measured in each temporary well point. Multiple depth to groundwater readings will be taken so it is reflectiveo f the water table level, to the greatest extent practicable. 0 The maximum estimated number of surface and subsurface soil samples, and the number of groundwater, surface water, sediment, and soil gas samples to be collected at each PSA during the RI are listed in Table 4-8. More details regarding locations, depths, and types of samples to be collected are provided in Appendix A and in the FOP. Actual numbers of samples collected will depend upon the data generated by the soil gas investigations and monitoring of existing wells. ^t In order to obtain analytical data, hydrogeologic data and other information downgradient of PSAs and in other parts of the Valley outside of the PSA properties, up to 40 additional deep boreholes will be drilled and soil and groundwater samples will be collected. Where soil m sampling is conducted and significant contamination (TCE/PCE, etc., not BTEX if solely of S suspected petroleum origin) is encountered, the Contractor will, at a minimum, collect one water II table and one bedrock groundwater sample from a borehole to be located no greater than 10 feet in the direction of suspected downgradient groundwater flow. This location can be vertically 5 contiguous to the soil sampling location, if appropriate. This sampling is presumed to occur Q during the later stages of Phase I or during Phase n after analytical data from Phase I have been evaluated, but may be conducted at any time following EPA approval. B E Twenty of the 40 boreholes will be converted to permanent monitoring wells throughout the 'p 1 PVGCS. The remaining 20 borehole locations will be selected to satisfy data needs of the project C as they arise and will only be installed following consultation with the USEPA. For example, the Confractor may recommend that one of these 20 borings be installed downgradient of a PSA % found to have contaminated media. The information obtained by the additional boring would be " used to further evaluate whether the PSA has contributed to regional groundwater contamination within that portion of the study area. Since circumstances like these cannot be predicted at this ij time, these 20 soil boring locations have not been identified on Plate 17. ^ • • • I The 20 boreholes will be grouted shut when sampling and water level measurements are "' completed. Thus, the boreholes provide a means of defining the nature and spatial distribution of 300113 65 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 i contamination, if any, at each location, but no new monitoring wells will be created. B Installation and Sampling of Permanent Monitoring Wells Tentative locations for 20 new monitoring wells are shown on Plate 18. These wells will be ~ installed toward the end of the drilling program. After data have been evaluated from the Existing a Well Sampling Program (SubTask 3.9) and sample results from the early PSA investigations, the S locations of these monitoring wells may be altered based on the new information and our updated understanding of the Valley's hydrogeologic flow system. Bedrock wells will be drilled approximately 110 feet into bedrock. Once the drill cuttings and g mud have been removed from die hole, geophysical logging will be performed. A maximum of g twenty-five feet of open-hole interval will be selected for die monitoring well intake. Multiple sampling intervals (i.e., nested wells, multilevel samplers) in one borehole may be necessary g based on the number of fracture zones that require monitoring. The rest of the open hole will be § packed off and grouted. If the field geologist determines the bedrock is incompetent and an "open hole" in bedrock monitoring well is not feasible, a PVC well screen having a slot-size opening of ^ O.Or inches will be installed. Four of the 20 new monitoring wells to be installed will be "background wells" placed upgradient of the contaminated groundwater areas. A set of two wells will be placed north of P Washington Borough along Rt. 31: one will be screened in the glacial materials and one will be open to bedrock. A similar set of two background wells will be placed up the Shabbecong Valley (side valley of main Pohatcong Valley). Presumably, these well locations are upgradient of the Vanetta Street, American National Can, BASF, and other production well cones of depression. When sampling results of existing wells are assessed, it may be determined that some existing well clusters can serve the same purpose as the proposed upgradient background wells. 9 A line of eight monitoring wells (four sets of two wells) will be installed across the valley throu^ Washington Borough, along Belvidere and Mine Hill Roads, as shown in Plate 18. Each well pair will include one screened near the bottom of die glacial overburden and one will be open to bedrock. These wells will help determine which part of the valley contaminants might be originating from and will help define the cone of depression (i.e., capture zone) created by the Vannatta Street well. A set of six monitoring wells (three sets of two wells each) will be installed across the valley along the far southwestern edge of Washington Township, along Little Philadelphia Road and Buttermilk Bridge Road, as shown in Plate 18. Each well set will include one well screened near the bottom of the overburden aquifer and one open to bedrock. These new wells, along with some of the existing wells sampled in the area, will enable the Contractor to determine the cross-sectional distribution of contaminants in the valley and also will assist in identifying w^ contaminant source areas within the valley. 66 300114 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 Two more monitoring wells will be installed along Brass Casde Road near the center of the NJDEP Well Restriction Area; one of these will be screened near the base of glacial overburden and one will be open to bedrock. These two wells will be used, along with existing monitoring wells in the area, to characterize the nature and distribution of contaminants downgradient of Washington Borough. Farther downvalley near the town of New Village, residential and monitoring wells exist. The sampling and analysis of existing wells in the area, performed during SubTask 3.09 of this RI, will provide adequate data to determine if VOCs are migrating this far downvalley, and what their distribution appears to be across the valley. Therefore, installation of new sentinel wells downgradient of the EPA- designated study area is not considered to be necessary. Out of the 20 new monitoring wells to be installed, at least ten of these will be drilled approximately 120 feet into bedrock. To do this, an outer casing will first be installed through the glacial overburden and set 10 feet into competent rock. Drilling will then proceed another 110 feet into rock. The wells will then be developed. Borehole geophysical logging (SubTask.3.12), including flow monitoring, natural gamma logging, caliper testing, fluid conductance and temperature measurements, borehole imaging, straddle- packer tests and flowmeter logging, will be performed as appropriate on the open holes at starting from the bottom. The tests will provide information on the variability of fractures and fracture permeability along the length of the hole, will allow groundwater samples to be collected from selected packed-off intervals and enable the Contractor to characterize the vertical distribution of contaminants in the bedrock aquifer. P Based on the results of the packer testing/sampling and the Borehole geophysical surveys, a specific 25-foot section of open-hole in each well will be selected for monitoring. The portion of open hole selected for monitoring in each well will be that section which exhibits the highest fracture permeability and the highest concentrations of contaminants (if present). According to NJDEP guidance, no permanent monitoring well should have screen interval or open-hole interval greater dian 25 feet in lengdi (NJDEP, 1992). Therefore, 25 feet of die open hole will be left open and the remainder of the open hole (i.e., 85 feet) will be packed off and filled with grout The annular space between the inner PVC and the outer steel casing will also be sealed with grout. If multiple monitoring depths are desired, the Contractor should consider packing off 25 foot intervals within the same borehole such that numerous monitoring points are obtained from a single borehole, if practicable and time and cost effective. No well screen will be installed in the bedrock monitoring wells unless lesser competent material (i.e., solution hole, highly-fractured zone, etc.) is encountered. Measures to be taken in the event that lesser competent material is encountered prior to monitoring well installation are presented in the FOP. The shallow monitoring wells will be constructed using a 15-foot long, 2-inch diameter PVC screen with sand filter-pack material around it, bentonite slurry seal, and cement-bentonite grout. Monitoring wells will be placed and constructed in accordance with die NJDEP Field Sampling Procedures Manual (May, 1992). 67 300115 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 Prior to sampling, die monitoring wells will be purged using low-flow procedures specified by the USEPA, Region n (USEPA, 1998). Water quality parameters (specific conductance, pH, Eh, I temperature, dissolved oxygen, and turbidity) will be measured during the purging process. Purging will continue until the water quality parameters have stabilized. Groundwater samples will then be collected. Details regarding drilling procedures, sampling procedures, and sampling locations are provided in the FOP. Surface Soil Sampling Surface soil sampling will be limited to areas of soil staining or documented releases to surface soils. Standard NJDEP sampling protocol (NJDEP, 1992) utilizing stainless steel trowels and bowls will be utilized. Surface soil samples will be collected from 0 to two inches below the ground surface. Investigation-Derived Wastes Soil cuttings will be minimal from the Rotasonic drill rig. As hollow-stem augers will only be used for shallow soil and groundwater monitoring, soil cuttings should be minimal as well. These p will be containerized in 55-gallon drums and staged in a common storage area until laboratory analyses are completed and proper disposal requirements are known. It is currentiy anticipated that all drill cuttings can be disposed of as non-hazardous waste in a municipal landfill. All waste water from the drill rig, well development water, and purge water will be temporarily stored in 55-gallon drums or a Baker tank until testing of the water samples is completed. All of the waste waters stored in the 55-gallon drums or in the Baker Tank will be picked up by a tanker truck and treated at the Pequest Municipal Utilities Authority POTW, located approximately four miles northwest of Washington Borough, or other facility if appropriate. More detailed information regarding the storage and disposal of IDW is presented in Section 8.1, The following describes each of the Borehole geophysical survey techniques to be performed. 3.12 Downhole Geophysical Investigations Downhole geophysical surveys will be performed innew and selected existing uncased (open hole) wells in the area using basic methods such as natural gartmia, resistivity, caliper, fluid temperature, and fluid conductivity logging methods. In addition, more specialized methods such I 68 300116 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt Q37-RI-C0-OZ # as acoustic imaging and heat-pulse or electromagnetic (EM) flowmeter measurements will be performed on select wells. Natural Gamma: Clay minerals contain a higher than average concentration of potassium-40 and uranium and thorium daughter products, most of which emit gamma radiation when they decay. Logging the vertical distribution of natural gamma radiation in a hole will show peaks where clay size particles are abundant. As a result, this is an excellent technique for identifying silty clay zones in the glacial overburden, identifying clay and silt pockets in fractures in the limestone bedrock; identifying shaly zones in the carbonated bedrock; and identifying potential water- bearing zones between the glacial silt and clay layers. Clay pockets in the fractured bedrock might indicate solution cavities where greater permeability exists. Silty clay zones in the glacial overburden will be correlated, if possible, between holes and will be used to map zones of low permeability in the overburden. These zones, if continuous to any extent, will deter the downward movement of water and contaminants and would increase the chances of lateral movement of contaminants toward a creekbed or other possible surface or shallow groundwater receptors. Thus, it is important to the understanding of the groundwater flow system that the presence of distinctive silty clay layers in the glacial overburden be determined. Resistivity: Logging devices measure the resistance, in ohms, of the earth materials surtounding the borehole (to a distance of about 5 to 10 times the electrode diameter) and the fluid in the borehole (Keys and MacCary, 1971). The single-electrode method is the simplest array design, but is a very useful logging tool, inasmuch as any increase in formation resistance produces a corresponding increase in the recorded resistance on the log. Resistance generally increases sands, sandstones, and limestones. Resistance generally decreases for shales, siltstones, and clay. The single-point logs are desirable for geologic correlation because of their response to changes in lithology. Single-point logs are also useful in detecting fractures; die fractures and fluids in the fractures cause the measured resistivity to decrease. Differential-resistance measurements, utilizing two electrodes, are very susceptible to the changes in borehole diameter, especially due to fracturing. This tool can detect nearly-closed fractures that may not be noticeable on a caliper log (Keys and MacCary, 1971). Acoustic Imaging: Acoustic devices are used much more frequently for borehole imaging than downhole video cameras. The borehole acoustic televiewer (BATV) operates by scanning the borehole wall with an acoustic beam. The tool needs to be centralized in the borehole to function properly. The intersection of a fracture with the borehole wall appears as a dark linear feature. The shape of this feature can be used to infer the strike and dip of the fracture. Caliper: A four-arm caliper tool measures the diameter of the borehole as it moves upward. Generally, the borehole is enlarged where the rock is fractured or soft. The enlargement occurs during drilling because the weakened rock is chipped away or eroded to a greater extent than «: 69 300117 Pohatcong Valley Gmundwater Contamination Site H/lay 1999 Statement of Work WAtt 037-RI-C0-02 h surtOunding rock. This log will distinctly show where solution features occur, especially along bedding planes. I Fluid Temperature: By recording the fluid temperature profile in a borehole, a log will be generated which may show anomalous zones of warmer or colder groundwater. Sharp contrasts I in borehole water temperature may indicate specific zones where groundwater is entering the I borehole or leaving the borehole. Fluid Conductance: By measuring a vertical profile of specific conductance in the borehole water, anomalous zones of conductivity may show where groundwater is entering or leaving the I borehole. I Heat-Pulse and EM Flowmeters: Borehole flow logging can be used to identify hydraulically conductive intervals intersecting boreholes. Water moves up or down the borehole based on vertical hydraulic gradients between the upper and lower sections and the rate at which I fractures can supply water to or accept water from the borehole. The heat-pulse flowmeter is a very-sensitive flow measurement device that can be used when discharges are small, whereas, an EM flowmeter is useful device when both low and high flow conditions are expected. The heat- I pulse flowmeter measures flow rate by detecting the time required that it takes for a small temperature pulse to move 2 cm up or down through a cylindrical section of the logging tool. The current version of the USGS heat-pulse flowmeter can measure borehole flow rates as small as p 0.04 L/min in boreholes ranging from 7.5 to 30 cm in diameter (Hess and Paillet, 1990; Paillet, 1994). I The movement of water up or down a section of open borehole can occur if the water level is higher or lower in one water-bearing zone than in another water-bearing zone. The I electromagnetic flow meter (EM flowmeter) is a very sensitive flow measurement device that can be placed at a selected section of a bore hole to measure the vertical rate of flow. The EM flow meter has a set of rubber diverters that seal against the wall of the borehole forcing water to be I diverted through a chamber in the meter. Ground water either flows up, down, or remains motionless in the bore hole based on the vertical hydraulic gradient between the zone above the diverters and the zone below the diverters. The flow meter measures the flow rate by detecting I changes in the EM field caused by flowing water. The greater the flow of water the greater the changes in the EM field. The meter is set at a number of levels in a well to get a full suite of discrete measurements for the full length of the open bore hole. The advantage of die EM flow I meter over other flow meters is that it detects flow over a much greater range. The heat-pulse flow meter is accurate at low flow rates and the spinner type flow meter is very accurate at high flow rates. The EM flow meter is accurate at low and high flow rate. I 3.13 Surface Water and Sediment Sampling I Initial data indicate that a downward vertical hydraulic gradient exists in the glacial I 70 300118 D Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 overburden around the study area, which implies that groundwater flow is vertically downward. 4 However, localized silty clay lenses in the glacial overburden may cause groundwater flow to be diverted laterally toward Pohatcong Creek or one of its tributaries. This might also cause some D contaminants to migrate laterally into the creeks. In addition, direct contaminant releases to surface water bodies, discharges of stormwater, or direct runoff from the PSAs might be entering the creeks. A total of approximately 10 surface water and 10 sediment samples will be collected away from anthropogenic sources for three purposes: (1) to identify the concenti-ations of contaminants in the stream that could cause impacts to human health or aquatic biota, (2) to assess surface water quality in specific reaches of the streams where contaminated groundwater fixjm suspected source areas could be emerging to the surface, and (3) identify areas of surface water/groundwater interactions and to better characterize the nature of the interactions. Tentatively, stream water and sediment samples will be collected at the following stream locations: Upstream of Washington to establish background conditions in Pohatcong L Creek, Shabbecong Creek, and Brass Castle Creek (total of three background water and three background stream sediment samples will be collected); One water and one sediment sample will be collected at the mouths of Brass CasUe Creek and Shabbecong Creek to determine if these watersheds are receiving ^^ and delivering contaminants to Pohatcong Creek; and |H| Five sets of samples (water and sediment) will be collected at locations along Pohatcong Creek between Mine Hill Road (upstream, north of Washington) and [" Edison Road in New Village. L These sampling locations have been tentatively identified and will likely be modified once the analytical results of the PSA investigations have been received from the laboratory and evaluated. The sampling locations may also be modified base on inspections conducted along the abandoned Morris Canal in Task 3. The tentative locations are shown on Plate 18. If sample stream water or sediment analyses indicate that contaminants are entering the creeks, four more samples will be collected in the vicinity where the contaminants are first discovered in order to identify a more precise location where the contaminants might be entering the creeks. Data from the surface water and sediment sampling will be used to evaluate risks to potential human and ecological receptors. 3.14 Surveying D Surveying of field sampling locations will be performed using portable global positioning m .^j 300119 Il^ Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 system (GPS) field survey equipment to identify the latitude, longitude, and elevation of all sampling locations except for groundwater sampling locations where only latitude and longitude measurements will be collected (depth of sample collected to be detennined by physical measurement at time of sampling). The GPS will not be used for collecting sensitive elevation data at monitoring wells and stream gauging sites because the geometry of the satellites used in GPS mapping result in a vertical accuracy which is approximately 2 to 3 times less accurate than die horizontal accuracy. All GPS data shall be postprocesed using data simultaneously collected by a surveyed GPS base station, or U.S. Coast Guard beacon, with a goal of sub-meter accuracy for each point collected. The ground surface elevation and well casing elevation of each groundwater and surface water monitoring point may be determined by a New Jersey-licensed surveyor. All surveyed coordinates (GPS or otherwise) shall be collected in decimal degrees, latitude and longitude, and in feet elevation above mean sea level. All such data shall be delivered in digital format in accordance with EPA's Locational Data Policy. For each spatial data point recorded (and differentially corrected if GPS), a "station identifier" (which will be the primary key for association in the database ~ see Section 6.1, below) shall be recorded in the data logger. The number shall be input into the data dictionary structure developed by EPA for the Site. The Contractor shall have the opportunity to provide input in the modification of the data dictionary, prior to collection of spatial data during the RI. The contractor may use EPA GPS equipment for this task (if available) and, as necessary, shall arrange to be trained in accordance with EPA GIS/GPS requirements (e.g., use of GPS equipment, EPA locational data policy, GPS data dictionary development and use, GIS database development, etc.). For EPA Equipped GPS data collections (Trimble setups), deliverables to EPA will be in Arc View Shapefile format exported from Trimble's Pathfinder Office (PFO) Ver. 2.11 post processing software. These Arc View Shapefiles will include all "Generated Attributes" available from PFO's Export Setup for "All Feature Types" In addition the Generated Attributes available for "Point Features" will include: height, standard deviation, and horizontal precision. Area Shapefiles will include the Generated Attributes: Area, Perimeter, Worst Horizontal Precision. All ArcView Shapefiles should be exported from Trimble's Pathfinder Office software in Geographic WGS84 coordinate system. For Non-EPA equipped GPS data collection efforts, deliverables to EPA will be either MS Access or dBASE .dbf tables in digital form (unless ArcView Shapefiles can be generated). In addition to database fields described in the projects data dictionaries, signed Latitude and Longitude in decimal degrees with 6 significant decimal digits will be included fields. These coordinates will be in Geographic WGS84 coordinate system. Also the following GPS metadata fields will be present for each record: 72 300120 Pohatcong Valley Groundwater Contaminati'on Site May 1999 Statement of Work WAtt 037-RI-CO-02 1. Receiver Type (name) P 2. PDOP (either mask value, max value, or average value for point/area collected) 3. Occupation Time or Unfiltered positions (epochs) and collection interval 4. Standard Deviation (points only) 5. Time and date 6. Feature Type (point or area). EPA must also be informed of what Base Station was used for differential corrections. For any spatial data point which is representative of multiple (greater than one) sampling points (e.g., soil and groundwater sample collected from same soil boring), the Contractor may join the latitude and longitude fields collected for the first sampling point to each other point represented by that physical location. Information obtained during the surveying of sampling points and reference points will incorporated into a site map prepared in a GIS format. Surveying will be an intricate part of both the smdy area and source area characterization programs to be implemented by The Contractor. 3.15 Quarterly Monitoring and Sampling The measurements of groundwater levels and die collection of groundwater samples from approximately 40 wells will be performed quarterly during die Phase I and II field investigations following completion of Task 3.11. Measurements of groundwater levels in monitoring wells throughout the study area are necessary in order to: determine groundwater flow directions; groundwater recharge and discharge areas; and groundwater flow velocities. These data, when plotted, will allow the Contractor to estimate the direction of groundwater flow in the aquifers as well as flow velocities over the regions of interest (based on the horizontal hydraulic conductivity of the aquifer). This information is necessary to assess die movement of groundwater within the study area, predict where and how quickly groundwater contaminants may be moving, and the probable locations of groundwater discharge. Data generated from this task will also enable the Contractor to evaluate how water levels fluctuate in response to seasonal changes in precipitation and evapotranspiration and in response to other influences such as pumping from municipal water supply, agricultural and residential wells. Where possible, groundwater elevation data from other overburden and bedrock monitoring wells at a PSA will be measured to determine the vertical hydraulic gradients and calculate vertical flow components between aquifers. Groundwater elevations and samples will be collected in all new wells and in 20 of the existing wells quarterly. ^W 300121 73 p Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 p In conjunction with groundwater level measurements and sampling, approximately 8 surface water samples may be collected each quarter in order to characterize temporal changes in water quality. The specific locations for sampling will be selected after analytical results from SubTask I 3.9 (Sampling of Existing Wells), SubTask 3.11 (Drilling and Subsurface Sampling), and I SubTask 3.13 (Surface Water and Sediment Sampling) have been received and evaluated. Following each quarterly sampling event, a letter report summarizing the analytical results from the groundwater and surface water samples collected will be prepared. Groundwater I elevation maps will also be prepared for each monitoring period, and flow directions and I hydraulic gradients will be determined. During the four events when groundwater elevations are being measured in monitoring wells, surface water flow rates and elevations will be measured at ten strategic locations (i.e., just before I a stream flows into another stream) along Pohatcong Creek and its tributaries. Tentative locations for flow-measurement stations and staff gauge elevation are shown Plate 18 and coincide with the I ten stations planned for stream water and sediment sampling (SubTask 3.13). These locations will be surveyed by a qualified biologist prior to the collection of stream flow measurements to avoid impacts to the endangered dwarf wedgemussel and bog turtle. The flow rates will be I calculated using cross-sectional depth and velocity measurements. The stream will be waded at each location and cross-sectional depth profiles and water velocities are recorded. The velocities will be measured using an electromagnetic velocity meter. Stream flow measurements at ten different locations will enable the Contractor to determine which sections of the streams are "losing" or "gaining." In losing streams, the stream water is recharging the groundwater system. In gaining streams, groundwater discharge is causing stream flow to increase. This type of I information is important to the understanding of the overall hydrologic flow system in the valley and processes which affect the migration pathways and velocities of contaminants. The information is also important for the development and the calibration of the groundwater flow I model (SubTask 5.05). I A rain gauge will be set up to measure daily rainfall amounts. In addition, minimum and maximum daily air temperatures will be recorded. These data will provide the amount of precipitation that falls and will allow the calculation of potential evapotranspiration. Such I information will be necessary as input data for the groundwater modeling effort. I 3.16 Landscape Restoration I Areas that are disturbed by drilling, sampling, or testing activities, or disturbed around the trailers, staging areas, decontamination pads, or waste storage areas will be returned as close as reasonable to prior conditions. This may require some grading, seeding, fertilizing, and mulching I of land areas (i.e., landscaping), or it may require the restoration of fences, pavement, or other p structures temporarily removed. For the purposes of estimating, it should be assumed that the 300122 I 74 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 Contractor will replace 10,000 square feet of sod, 10,000 square feet of macadam, 100 cubic P yards of top soil, and 5,000 square feet of mulch during restoration activities. These services may be performed by a subcontractor, as necessary. 3.17 Demobilization All utilities used for the operational headquarters will be disconnected. The Contractor and it's subcontractors will dismantle, remove, and transport as necessary, any temporary strucmres, decontamination pads, trailers, staging areas, etc. The Contractor and its subcontractors will perform all work necessary to demobilize all equipment, tools, and personnel used to perform the field activities described in Task 3. All equipment and tools will be properly decontaminated before they are demobilized from the area. IDW will be removed from the area and freated or disposed of, as appropriate. Trash and other wastes will be removed from all areas of operation, sampling, and drilling sites, and disposed, as appropriate. The Conductor will transport all project-related files and data bases to a secure location for future use on other tasks. 3.1S Phase I Report An report (approximately 50 pages in length) will be prepared to summarize the activities performed and the data generated during Phase I. The purpose of this report will be to present preliminary findings from the Phase I investigations and to recommendth e locations and types of additional studies that need to be performed in Phase II to furdier evaluate specific PSAs which are likely source areas. This report will discuss groundwater flow directions in the valley, spatial distribution of contaminants in the streams and aquifers, and the characteristics of the "hot spots." For each PSA investigated, the findings will be presented and the PSAs will be assigned to one of three categories: 1. Contamination found (retained for further investigation during Phase D); 2. Minimal contamination found, but not as severe as Group 1 above (retained for further investigation during Phase n or deleted from PSA list, as appropriate); and 3. No contamination found or suspected (deleted from PSA list). The categories will be determined using criteria provided in Section 7.1.2. ^B ^5 300123 I * Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 I PHASE n RI I 3.19 Phase U RI Work Plans A work plan will be prepared to present the Phase n RI scope of work, rationale, and estimated costs. After approval by the USEPA, a Phase II FOP will be prepared. This FOP will I not duplicate material contained in the Phase I FOP. It will simply contain the maps, tables and I text that are necessary to direct the execution of the Phase EI investigations. I 3.20 Phase II Mobilization Trailers, equipment, supplies, and personnel will be mobilized to the Study Area. The same locations will be used for the field office and IDW storage as was used in Phase I. Utility I hookups will be performed as described in Section 3.7. I 3.21 Surface and Borehole Geophysical Investigations If needed, additional surface geophysical surveys will be performed at, or in the vicinity of, the PSAs being investigated in Phase II. These will be performed only if there are outstanding questions or issues related to fracturing and preferred flow pathways in the bedrock beneath or I downgradient of the PSAs. Downhole logging will be conducted in new bedrock boreholes drilled in Phase n. I 3.22 Drilling and Environmental Sampling At each of the PSAs to be investigated during Phase II, additional surface and subsurface samples will need to be collected to improve the definition of geology, hydrogeologic conditions, and the distribution of contaminants. This additional data will be used to more completely assess whether the PSA is in fact a source area for contamination, and to quantify the relative magnitude E of impacts that have occurred to groundwater, surface water, surface soil and stream sediments in I the area as a result of past releases. Until the results from Phase I have been evaluated, it will not be possible to identify which PSAs will need to be investigated during Phase n, nor is it possible to state here the quantity and I types kind of environmental samples will need to be collected. For the purposes of cost estimating, it is assumed that six PSAs will be investigated during Phase II. It is also assumed I that the following will be collected for each PSA: P 300124 I 76 I Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 # • four soil gas samples; • three subsurfacsubsurface soisoill ;samples , one shallow groundwater sample, and one deep I groundwateiinHwatPr samplcamnlfe^ fmfrom par-each or>ff foufnnr soisnil boringshnrina To obtain the appropriate amount of samples needed to perform the HHRA, statistical I evaluations will be performed prior to identifying Phase n sampling frequencies. I 3.23 Hydraulic Testing I Pumping tests and slug tests will be performed in order to determine the hydraulic properties ^^ of the geologic materials , including hydraulic conductivities, transmissivities, specific yields, and ^B storage coefficients. In addition, an effort will be made to determine spatial variability and trends ^^ in these characteristics, to determine to the degree hydraulic properties are different "on" and "off fracture traces and fault zones, and to determine what anisotropic conditions exist, both in • the bedrock and the overlying glacial overburden. Tentative locations for pumping tests are " shown on Plate 18. These locations may be altered based on the evaluation of data generated during the of Phase I investigations. • If an NPDES permit for surface discharge of the water can be obtained, then the water produced during pumping tests will be passed through activated carbon (or equivalent treatment method) and discharged to a stream or drainage ditch (in an area where the recharge is not expected to impact the test). Otherwise, all pumped water from hydraulic testing activities will be I temporarily held in storage tanks and hauled to the local POTW for ti^atment and disposal after it is tested for disposal characteristics. This quantity of water is estimated to be approximately 26,000 gallons. I I Multiple-well, constant-rate pumping tests (i.e., one pumping well and several monitoring wells) will be conducted using monitoring wells at three different locations shown on Plate 18. The pumping well and at least one additional well will be screened in the bedrock. Pumping rates will be determined by performing step-drawdown tests and by the evaluating the rate required to I induce drawdowns in the observation wells. For each of the bedrock pumping tests, at least one monitoring well will also be screened in the glacial overburden in order to evaluate the degree of hydraulic connection between the bedrock and the overburden. In addition, water level I 4 77 300125 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0'02 monitoring of surface water bodies within the immediate area will be performed. Water levels in the pumping well and the monitoring wells will be automatically recorded using pressure transducers and a data logger for at least 72 hours prior to the start of the test, during the pumping test, and at least 72 hours after the pump is stopped to measure recovery. Water levels in nearby surface water bodies will be measured at the same intervals using a staff gauge. Additional, more short-term pumping tests, may be performed to test the interconnectiveness of certain groups of wells open to firactures in the bedrock. Preliminary locations for the pumping tests are shown in Plate 18. Water levels will be monitored in the pumping well and one or more monitoring wells using pressure transducers and a data logger up to 12 hours after the pump is turned off. Water generated during the tests will be containerized, sampled, and disposed of as described previously. Ten standard slug tests will be performed in overburden wells screened in glacial sediments where the hydraulic conductivity values are expected to be lower. Air slug tests will not be performed because it is assumed that many of the wells used for hydraulic testing will be screened across the water table with portions of the screen exposed to the vadose zone. Water levels in the tested wells will be recorded with a pressure transducer and recorder as the solid slug is introduced to the well (falling-head test) and as the slug is removed(rising-hea d test). * The pumps, transducers, and other equipment will be decontaminated after each test. 3.24 Dye Tracer Tests The concept of dye tracing, in its most simplified form, is the injection of a substance into groundwater at a known location and measure time and the recovery rate of the substance at a distant location over a period of time. From this, groundwater flow paths and velocities can be ascertained to a higher degree of accuracy. Other groundwater flow characteristics which can be determined are coefficients of dispersion (i.e., whether the dye flows in a slug or is dispersed during its migration) and rates of mixing. Dye tracing involves the tagging of a discrete sample of water with an appropriate tracer and monitoring the arrival of the tracer- laden water at various groundwater sampling points. The arrival of the dye may be observed visually or it may be quantitatively measured with instrumental analyses that reveal its presence. Mb g Dye tracing is generally the most practical and satisfactory method to provide information on the hydrology of karst groundwater systems. Qualitative dye ti-acing with various fluorescent dyes and passive detectors, consisting of activated coconut charcoal or surgical cotton, can be used to identify point-to-point connections between points of groundwater recharge (i.e., potential spill sites) and discharge (i.e., residential or public water supply wells). P 300126 78 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 Fluorescent dyes are perhaps the most widely used because they can be detected at 4 concentrations well below the ability to visually detect non-fluorescent dyes. Four commonly f^ used fluorescent dyes are rhodamine WT, optical brighteners, Direct Yellow 96, and fluorescein. H The presence of rhodamine WT or fluorescein dye is indicated by elutiiating exposed coconut charcoal in an alcohol solution and visually checking for the characteristic yellow-green color. ^ Optical brighteners and Direct Yellow 96 are recovered on swatches of undyed surgical cotton. ^_ The presence of these dyes is confirmed by viewing die cotton swatches under ulti*aviolet light. The most productive way to conduct a dye tracer study is to place three or four different dyes ® at separate locations/wells in the groundwater flow system and monitor a single point of groundwater discharge (e.g., a pumping well or receiving stream) to determine the arrival time pi and breakthrough curve of each individual dye. This can be done because each dye has its own "^ specific spectrum of fluorescence when exposed to ultraviolet light; identification and ^ concentrations of each dye can be determined in water samples simultaneously using a M fluorimeter. Use of other tracers, such as bromide, iodide, or total dissolved solids (TDS), were considered for use as tracers, but bromide is more cosdy to analyze (neutron activation analysis), ^ iodide and TDS cannot be detected at the ppb level like dyes, and TDS could actually cause W degradation to local groundwater quality. During the Phase n investigations, three different fluorescent dyes will be injected in monitoring wells or boreholes at various distances and directions from a pumping well. Water ^^ samples from the pumping well will then be sampled at a regular frequency and analyzed for the ^B dyes using a fluorescence specfrophotometer. The dyes are nontoxic and can be detected at the parts per billion level, which is far below the concentration visible with human eyes. A,permit ^ from NJDEP will be required to perform these tests. B Two different types of dye tracer tests will be conducted during the Phase II RI. The first type of tracer will be performed in conjunction with the long-term pumping tests described in ft SubTask 3.23. The locations of the tests will be determined following the collection and 8 evaluation of data in Phase I. These tests will provide information concerning prefened .flow pathways, hydraulic anisotropy, and dispersion coefficients for the geologic materials in each of ' B the test areas. Three different dyes (fluoroscein, rhodomine, and cosine) will be introduced into 8 different monitoring wells (one dye in each well) about two hours before a pumping test begins. The dyes will also be mixed vertically within each monitoring well prior to start of the pumping :i| test. During the pumping test, grab samples will be collected from the pump discharge every 15 '^ to 20 minutes. These samples will be placed in 40-ml VOC glass vials and will be analyzed for the tracers using a fluorescence spectrophotometer. The arrival time and breakthrough curves for B each tracer will indicate how rapidly the tracer was moving toward the pumping well (velocity) ^ and how much it was dispersed or sorbed during its migration, gr-j The second type of tracer test to be performed during the Phase n RI will be larger scale and will involve large production wells in the area. Dye tracers will be introduced and mixed within g three monitoring wells located around three different productions wells. The wells currendy planned to be evaluated are the Vannatta Street well, the Dale Avenue well, and the American 79 300127 Pohatcong Valley Groundwater Contaminati'on Site May 1999 Statement of Work WAtt 037-RI-C0-02 4 National Can production well. These production wells will have a bleed-off pipe widi a carbon absorption canister placed inline so that the tracers can be captured over one- or two-day periods before the canisters are changed out. The pumping wells will each be monitored up to three months to determine the arrival time, breakthrough curves, and dispersion of each ti-acer during its migration to the wells. The data will provide valuable information on flow velocities, groundwater flow directions, the capture areas for each well, and what the source areas might be for contaminants found in each well. For both types of tests , the dyes will be injected in the monitoring wells as slugs at the beginning of the tests (i.e., a one-time slug). The wells will be selected at different orientations from the pumping well in order to determine whether a well is capturing groundwater preferentially in one direction or is capturing from all directions equally. For the American National Can Company test, one of the dyes will be placed into the glacial overburden to determine the velocity of tracer movement downward toward the bedrock aquifer. All other wells involved with the dye tracer tests will be screened in the bedrock aquifer, 3.25 Ecological Sampling Ecological sampling will not be performed until an Ecological Risk Assessment has been conducted, and appropriate assessment endpoints identified. If ecological sampling is necessary, the list of contaminants of potential concern monitored in these ecological sampling efforts will be refined to include only certain contaminants identified in soil and groundwater samples, and p their chemical/biological breakdown products. If, after the completion of the ERA, it is determined that a field evaluation of ecological effects is needed, then a scope of work for these activities will be prepared (after consultation with EPA) and submitted in a Work Plan Addendum, 3.26 Surveying Surveying of field sampling locations will be performed using portable global positioning systems (GPS) field survey equipment to identify the latitude, longitude, and elevation of all sampling locations except for groundwater sampling locations where only latitude and longitude measurements will be collected. The GPS will not be used for collecting sensitive elevation data at monitoring wells and stream gauging sites because the geometry of the satellites used in GPS mapping result in a vertical accuracy which is 1.5 times less than the horizontal accuracy. The ground surface elevation and well casing elevation of each groundwater and surface water monitoring point will be determined by a New Jersey-licensed surveyor. 3.27 Landscape Restoration p 80 300128 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 4 Areas that are disturbed by drilling, sampling, or testing activities, or disturbed around the trailers, staging areas, decontamination pads, or waste storage areas will be returned as close as reasonable to prior conditions. This may require some grading, seeding, fertilizing, and mulching of land areas (i.e., landscaping), or it may require the restoration of fences, pavement, or other structures temporarily removed. For the purposes of estimating, it should be assumed by the Contractor that it will replace 2,500 square feet of sod, 5,000 square feet of macadam, 50 cubic yards of top soil, and 5,000 square feet of mulch during restoration activities. These services may be performed by a subcontractor, as necessary. 3.2S Phase II Demobilization All utilities used for the operational headquarters will be disconnected. The Contractor and its contractors will dismantie, remove, and transport as necessary, any temporary structures, decontamination pads, trailers, staging areas, etc. The Contractor and its subcontractors will perform all work necessary to demobilize all equipment, tools, and personnel used to perform the field activities described in Task 3. All equipment and tools will be properly decontaminated before they are demobilized from the area. IDW will be removed from the area and treated or disposed of, as appropriate. Trash and other wastes will be removed from all areas of operation, sampling, and drilling sites, and • disposed, as appropriate. The Contractor will transport all project-related files and data bases back to our Iselin, New Jersey office and organize them for use during the subsequent tasks. TASK 4 SAMPLE ANALYSIS f^ The following sections describe the elements of a typical sample management, tracking, analysis, and validation under Task 4.0. Detailed procedures for diese programs are provided in the Field Operations Plan (FOP). 4.1 Sample Management and Tracking Environmental samples and Quality Assurance Quality Control (QA/QC) samples collected during the RI will be managed by the Contractor's sample management team. The sample management team will be comprised of a sample custodian who will be a member of die field sampling teams, and the sample manager who will track die custody of the samples from the time of collection until validation of the analytical data.. Prior to each field sampling event, the sample P 81 300129 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt Q37-RI'C0-02 custodian will communicate with sample manager/QA Officer and the Field Operations Leader (FOL) to confirm the sampling media, location, volume and analyses required for each sample to be collected and will ensure that all samples have been collected according to the most recent U.S. EPA sample collection directives. The sample custodian will participate in the sample collection activities, preserve the samples as necessary, and complete all the necessary documentation (chain-of-custody forms, sample labels, etc.) Subsequent to the sample collection, the sample custodian will inspect the chain-of- custody forms, sample labels and transport the samples at 4oC to the command post. The sample manager will take receipt of the samples from the sample custodian, and inspect the sample cooler noting and correcting any deficiencies. The Contractor's sample manager will coordinate with EPA's CLP for the analysis of the samples or with an independent laboratory should the sample require special analytical services. Within the scope of sample management, the Confractor's sample manager will also be 3^ responsible for the following duties: Maintaining a data tracking spreadsheet which will monitor all samples delivered to the laboratories and will contain field sampling and laboratory information pertinent to each sample; 4 Management and organization of all paperwork related to sample collection and sample custody. Separate files will be established for the CLP and independent laboratory samples. All binders or files will be clearly marked and dated with their contents; Ensuring that sample specific information including sample location, identification, media and other related information is provided to the Contractor's GIS Database Manager; Arranging fixed-based laboratories under EPA's CLP; Artanging analysis of potable water samples for drinking water analysis by EPA's ESD laboratory; Preparing and shipping samples requiring geotechnical, geochemical, and engineering analysis to the appropriate independent laboratories; Filing paperwork related to sample collection, custody and data tracking will be filed in a secure location with access only through the sample manager. Ensuring sample containers meet the specifications identified in the FOP, that new containers are ordered as necessary, and ensuring the proper sample preservation solutions are on site; Verifying that sample identification procedures have been consistentiy P followed by field sampling personnel; 82 300130 ^fi Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 " Ensuring field logs and chain-of-custody procedures are followed, and quality control samples (blanks, duplicates, spikes) have been collected at the required frequencies; and ° Ensuring that data and documentation described above is maintained in a retrievable manner and data and documentation is archived and entered into a document control file. The Contractor's sample custodian will be a member of each field sampling team and the costs associated with his/her labor would be incurred under Task 3 (Field Investigation). Therefore, no additional costs for die sample custodian will be incurred under this SubTask. The Contractor's sample manager will be present on site for the duration of Phase I and Phase n field sampling activities , The sample manager will be responsible for the management and tracking of approximately 361 soil samples, 31 sediment samples, 49 surface water samples, 544 groundwater samples, 20 disposal characterization samples, and 740 QA/QC samples (see Table 4-9), QA/QC samples include all trip blanks, field blanks, duplicates, matrix spike, AND matrix spike duplicates, described in this document. 4.2 Sample Analyses CLP Analysis # Environmental samples and QA/QC samples collected during the Phase I and II RI will be analyzed by EPA's CLP for TCL low concentration volatile organic compounds (VOCs), TCL low concentration semivolatile organic compounds, and TAL dissolved and total metals analyses using USEPA Statement of Work ELMO 4,0 (for inorganics) and OLMO 3.2 (for organics). The analytical data provided by EPA's CLP will provide the RI team with reliable, high quality analytical data. Tables 2-3 through 2-8 present the analytes and respective method detection limits that will be achieved by the CLP laboratories. For all soil samples analyzed by EPA's CLP, the Contractor will utilize the methanol preservation sample collection method described in Section 9.3 of the NJDEP's "Methodology for the Field Extraction/Preservation of Soil Samples with Methanol for Volatile Organic Compounds, February 1997." ESD Laboratory Analysis Approximately 30 potable water samples collected from homes within and downgradient of the PVGCS, along with approximately 10 QA/QC samples, will be analyzed for the National Primary Drinking Water Standards list by EPA's Environmental Service Division (ESD) laboratory in Edison, New Jersey. If EPA's ESD laboratory cannot analyze the samples, an ^s 83 300131 Q Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 i independent laboratory capable of performing the appropriate analyses will be procured. 43 Independent Laboratory Analysis In addition to die confirmatory sample analyses, approximately 10 water and 10 soil samples will be analyzed off site for geotechnical, geochemical, and engineering parameters. The laboratory performing these analyses will be procured under the Contractor 's DAS program. The geotechnical, geochemical, and engineering analyses results will be used during the Feasibility Study to assist in the evaluation of remedial technologies and remedial alternatives potentially applicable to the site. Tables 4-10, and 4-11 provide a listing these parameters and the how the results will be used in the Feasibility Study. After completion of the Phase I field work, approximately 5 soil and 7 water samples will be Q submitted for TCLP waste characterization analysis including VOC, SVOC, ignitablity, corrosivity, and reactivity. Waste characterization analyses will be performed at an off-site laboratory procured under the Contractor 's Delivery of Analytical Services (DAS) program. Soil samples for waste characterization purposes will be collected from drill cuttings stored in 55 gallon drums at a ratio of one sample for every 40 drums of cuttings produced. Based on the estimated number of drums of soil which will be produced during the Phase I RI (about 200 drums), the Contractor will collect approximately 5 soil samples for waste characterization purposes. 4 The Contractor will collect water samples for waste characterization purposes at a ratio of one sample per every 10,(XX) gallons of development, purge, and decontamination waters generated during investigatory activities or at a frequency required by the disposal facility. Based on the estimated volume of development, purge, decontamination and other investigation-related water samples which will be generated during the Phase I RI (approximately 70,000 gallons), the Contractor will collect approximately 7 water samples for disposal characterization. The seven water samples will be analyzed for total VOC, SVOC and metals by a CLP laboratory and for ignitability, reactivity, and corrosivity at an independent laboratory. After completion of the Phase n field work, approximately three soil and two water samples Q will be collected and submitted for the identical waste characterization analyses described above, 4 A Delivery of Analytical Services Laboratory Procurement The Contractor shall prepare Laboratory Services Requests (LSR) for all non- RAS D parameters. The LSRs will include, but are not limited to, a statement of work, the required digestion/analytical methods, data deliverable requirements, QC requirements, estimated number of samples, restrictions, and policies. The LSRs will also request the submittal of the laboratory service vendor's certifications, QA manuals, applicable SOPs, and resumes of key personnel. The LSRs will then be combined with the Contractor's r's appropriate contractual agreements in a proposal request package. The LSRs which are returned to the Conb-actor will be evaluated under S'^ 300132 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 this SubTask. P The Contractor will select two fixed-based laboratory subcontractors. One of the two off-site I laboratory subcontractors will be capable of analyzing soil and waste using TCLP procedures and other disposal characterization methods. The second off-site laboratory will be selected for the analysis of the geotechnical, geochemical, and engineering parameters identified in Tables 4-10 1 and 4-11. If necessary, a third laboratory will be procured for the analysis of potable water |^ samples collected in Task 3.8 should EPA's ESD be unable to perform the drinking water • analysis. Greater detail on the Contractor's DAS Program is included in the FOP. 4.5 Sample Validation t This is an optional task that will be performed (upon authorization) to confirm and document I the laboratory identified and qualified compounds. Laboratory data packages will undergo a |^ formal validation procedure to examine laboratory compliance with quality assurance I requirements and other factors which determine the quality of the data. The validation will be performed in accordance with EPA Region 2 Standard Operating Procedures for Organics and Inorganics. The Contractor will perform the data validation for chemical data produced during the Phase I and n field investigations. I At a minimum, the following factors will be examined during data vaHdation: P sample holding times; sample chain-of-custody records; I GC/MS tuning criteria; initial and continuing calibration; I interference check analyses; method blanks; I laboratory control sample results; detection limits; I laboratory blank contamination surrogate spike recoveries; I matrix spike and duplicate sample analytical results; field blank contamination; I internal standard area; compound identification criteria; I 85 300133 I I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 4 • furnace analyses; and I • • serial dilutions. I The following table presents the estimated maximum number of analyses to be I validated (by analytical method) for organics and inorganics. ^j.,;^-''^^!fS:?::^l»f»s»r-;;H^-,;^ Sfcfc:^'^"^*^^^'^^ iMilSfefc t I • ;:;l-;iiiiotiBi» , •'etPJQtffuiJe"; '.- CLP Inorganic Media ^ i-:Mi6c CLP .-••rA" IniSreianic*.;!:-;;--. •:t:Sbw=btiii6'- P'Sbw IUI04:a: gOtOMO 3i- ?;'-:;;sow • CtPOrgai^?- ,, /. Aiialysss I r OtOMb 3.2 Wat er 1,154 965 901 149 124 116 3,409 f Soil/ 290 290 262 168 168 152 1,330 . Sadi ment i Sub 1,444 US5 1,163 317 292 65 4,739 total * SOW = Statement of Work (the current CLP SOWs are being revised). I Total VOC, SVOC. and Metals Analyses Requiring Validation = 3,121 I * = Analyses of samples for engineering parameters and waste disposal characterization (solids) not included. I 4.6 Quality Assurance Officer During the Phase I and II field investigations, the Contractor's Quality Assurance Officer (QAO) will perform periodic inspection of RI field activities and inspect records I maintained by the sample manager. The QAO will document the Contractor's compliance with approved protocol and procedures and report the results and any corrective action necessary to the Contractor's Project Manager. The QAO's responsibilities are explained in f greater detail in the FOP. I TASK6 DATA EVALUATION I 6.1 Database and GIS Development 300134 I 86 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 As Phase I and n analytical data are validated and found to be acceptable, they will be 4 electronically transferred into the Pohatcong Valley Data Management System, along with other sampling-related information, by a data technician and checked against the original laboratory reporting sheets to verify that the information entered into the data management system is accurate. To the greatest extent practicable, data should be transferred electronically, with minimal operator input to minimize ertors. In support of remedial investigation and feasibility study activities at the Pohatcong Site, the Contractor will construct a computerized database management system for all applicable study areas. The database will be used as the baseline for the project to store and present data. Further, the completed database will facilitate integration into GIS, mapping and modeling packages for rapid evaluation and analysis. The purpose of the database will be to: " Provide a standardized format for data storage and presentation. Integrate groundwater, soil, and geological databases with site maps and images. Minimize QA/QC of data and create an electronic warehouse of information related to the project. Interface with modeling and visualization software. The database shall be a relational database compliant with the RAC. The database program P which is selected for development of the Pohatcong database shall be selected based upon ease of use, compatibility with a variety of off-the-shelf software packages, reliability, and seamless transfer into GIS packages. Upon completion of the RI, individual elements of the database will be formatted for transfer to the EPA Oracle database system. In construction of the Pohatcong GIS, mapping will be performed in AutoCAD and ArcView. Database Files Electronic files containing validated analytical data will be formatted, then direcdy transferred into the database. All data upon entry into the system will undergo a 10 percent QA/QC output verification check to ensure proper transfer and entry into the system. This will entail checking output from the database against original hardcopy reports and laboratory databases. Analytical data generated by fixed-based laboratories will be manually entered into the data management system unless the laboratories can provide the data in an electronic format. Within the database, separate tables should be created to store soil, groundwater, analytical, GPS and geologic data. The tables should be related by defining a primary key, hence the term relational database. The primary key then serves to integrate tables and provide a frame of reference for indexing, sorting, and combining data. For example, each data element generated at P 300135 87 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 4 an intrusive boring (e.g., surface soil, shallow soil, shallow groundwater, deep groundwater, and the GPS point) should have a primary key, or station identifier, associated with it which relates it to each other data element. The station identifier shall be comprised of a seven character data field consisting of the abbreviated Site name, sampling location, and sample number, and shall be represented by a unique geographic location which is noncontiguous with any other horizontal location. Sample Labeling Each sample will be assigned a unique sequential number (see SOP A.l) at the time of sampling, and a RAS sampling code if it is being sent off site to a CLP laboratory, which will be permanently affixed to the sample container with polyethylene tape to prevent the loss of the label during shipment. The sample label will be filled out using indelible ink and will include the following information: Project name; Site ID; Sampling location; Sampling date and time; * Analyses to be performed; Preservative; and Sampler. Field personnel will be required to write the sample ID on the samples label. The sample ID will consist of die site name, a three-letter acronym of the PSA study site (e.g., American National Can Company = ANC), the media type (e.g., SS for surface soil, GW for groundwater), a sequential sample number, and depth, when applicable. The site-specific sample code will be based on die following system: V Site- AlwaysPV • PSA or Other Location (see Table 3-4 for the sample identification nomenclature) Sampling Location Number - Will be used for each sampling location at the PSA or Other Location (typically 01 through 10), The number will be sequentially generated based upon the order sampling is performed. Where a number of 300136 I 88 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 # different sample types will be collected at a single location, the number shall be duplicated for each sample type collected at that location'. w? S-: o Sample Type (see below) M Im SG - Soil Gas Sample SB - Soil Boring Sample SD - Sediment Sample m DS - Waste Disposal Sample (Solid) SS - Surface Soil Sample DL - Waste Disposal Sample (Liquid) P MW - Monitoring Well Sample QC - QA/QC Sample 1 WP - Well Point Groundwater Sample •m SW - Surface Water Sample DW - Domestic Well Water Sample MI - Macroinvertebrate Sample 'Note: die preceding three fields. Site, Location and Sampling Location will be concatenated into one number which shall be the key field for association in the database. " 89 300137 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 4 • GD - Groundwater Sample Collected for Dye Tracer Study • Sample Number - Will be used for each sample location in each matrix and well point sample (typically 1 dirough 9), • Sample Depth (For soil borings and wellpoint groundwater samples only) - Sample depth will be placed in parenthesis after the sample location number. The depth will represent feet below ground surface (bgs). • QA/QC Identifier - Will be placed as the last character when applicable and will be used to identify whether a sample is a duplicate (D), a field (rinse) blank (F), a trip blank (T), a confirmation sample (C), or a matrix spike duplicate (MSD). For example, one surface soil, two soil boring, two groundwater (well point) samples, and the first trip blank sample, from a the first drilling (sampling) location at American National Can Company would be labeled: SampU Samp I Sample Sample QA/QC I Final 4 Site ^&ali|^ Jig le ; Number Depth Identm Sample No. r ••• -••• •••oiS^'^^ T^irati Type (bgs) er on PV ANC 01 SS 1 N/A NA PVANCOl-SSl PV ANC 01 SB 1 (25) NA PVANCOl-SBl (25) PV ANC 01 SB 2 (45) NA PVANC01-SB2 (45) PV ANC 01 WP 1 (50) NA PVANCOl-WPl 1 (50) PV ANC 01 WP 2 (270) NA PVANC01-WP2 (270) PV ANC 01 QC 1 NA T PVANCOl-QCl (J) I-"— -.—1 A surface soil sample and a shallow soil boring collected from the next sequential sampling location at American National Can Company would be labeled: I 90 300138 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-O2 ^Sampli Samp Sample I' Sample fQ^QC 4 s 1 Final • Sit& Loeati^ le ,^ Numfosr' { ' " Mentif! .h^,*"-Sampl e ^o. *f! J It -:.. ' oir E^ecats '^ Type (Ssgs> PV ANC 02 SS N/A NA PVANC02-SS1 PV ANC 02 SB (17) NA PVANC02-SB1 (17) Therefore, by searching on a sampling point in the GIS by the primary key, the user vould be provided will all sampling, geological and spatial data attributed to that sampling point. The first group of tables within the database will contain information pertaining to analytical, chemical, and physical analyses of soil, soil gas, groundwater, sediment, and surface water samples. To facilitate this process, a standardized data deliverable format will be distributed to the sub-contracted mobile laboratory and field personnel to ensure consistency in data collection and format. The database will dien be constructed by manually entering existing analytical data and incorporating data provided by laboratory and field personnel during RI activities, unless diis information can be obtained in suitable digital format. Data fields in the database will include the • primary key (consisting of sample site, location, type and number), date analyzed, date sampled, chain of custody number, analyte detection limit, lab qualifier, validation qualifier, lab value, validated value, laboratory, and field personnel involved with sample collection. The data technician will be responsible for entering much of this information into the database, however, to minimize ertor, wherever possible the data should be integrated into the database in electi-onic format and subsequendy checked for error. Data files will also be created containing information related to geologic and field data. This information will include integration of available geologic and field sample data. Data collected during the investigation relating to geologic and field screening information will be determined by the field geologist or engineer. Fields in the database will include sample number, depth interval, sample date and time, field personnel, water level, soil type, and other field analyses. Other data files will contain information related to the location of monitoring wells, potable wells and sample location points. This will include determination of latitude/longitude and elevation coordinates for monitoring wells and sample locations using GPS equipment or existing surveyed location maps. The survey coordinates for monitoring wells and sample locations will be used for all applicable maps developed for the RI/FS. Upon completion of RI activities, the data files will be formatted for ti-ansfer to the EPA ^W 91 300139 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-C0-02 Oracle database system. 1 6.2 Evaluation of Analytical Data I Work under this task will be performed throughout the Phase I and II RIs to identify sources of contamination, focus additional soil and groundwater sampling, and to characterize the I hydrogeology of the site. Data generated by the analysis of environmental samples will be evaluated on site to the extent practicable. I Evaluation of the analytical data generated by sampling activities at the PVGCS will include sorting and statistical summaries of data; comparing data against MCLs, EPA's Soil Screening I Levels (SSL) or other screening levels to establish constituents of concern; comparing groundwater quality data from the 1980s against data generated by the RI; and other datainterpretive work for each of the analytical data sets generated during Tasks 3 and 4. The f following presents a summary of the analytical data generated by the Phase I and Phase n RI I whioh will require evaluation. p ^vSubtaskNa Phaw , p DataTo Be Evaluated < • •::;.;:.-5,s!?J*3^:;,iK 3.01 1 Collection and Evaluation al Existing Existing Well Locations, Water Quality Data, Data Groundwater Bevation Data, Soil Data, Well I Yield Data 3.09 1 Sampling Existing Wells and Quality Analytical Results; Groundwater Eieation Data; I 3.15 Sampling Sampling Locations 3.08 i&ll Soil Gas Sampting Analytical Data; Location of Sampling Points & 3.20 I 3.11 t&ll Drilling, Sut^surfaca Samf^g, and Analytical Results: Sampling 1 ocations & Well Installation 3.20 3.13 I&ll Surface Water/Sediment SaiDpling Analytical Data; Location of Sampling Points I & 3.20 I I Data collected during the Phase I RI will be used in this task to revise the Hierarchical List of Sites presented in Appendix B, determine which sites will undergo drilling and subsurface sampling in Phase I, and determine which sites are likely sources of contamination and require a I more focused investigation during the Phase II RI. To satisfy these objectives, the procedures 300140 I 92 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-CO-O2 described in Section 4.6.1 will be used to evaluate analytical data generated by sampling activities P at a PSA and to revise the Hierarchical List of Sites. 6.3 Evaluation of Other Data Many of the subtasks during field investigations will be generating data which are not "analytical" data (i.e., not sample analyses). These data sets and information are presented at the end of this subsection. Several SubTasks, such as the hydraulic testing, dye tracing, and borehole drilling SubTasks, will be generating large amounts of data that will not be entered into the GIS database in raw form. The field data need to be inteipreted and reduced down to useful information which can then be entered into the GIS database. As an example, pumping test data will be interpreted and a few values of hydraulic conductivity, porosity, and storage coefficients will be entered into the database. Geological information from the RI borehole logs, existing well logs, and downhole geophysical logs need to be interpreted and information put into the database regarding thickness of glacial overburden, thickness and elevations of clay lenses, elevation of top of weathered bedrock, elevation of top of competent (less weathered) bedrock, etc. These geologic data within the GIS can then be used to produce geologic isopach maps, top of bedrock maps, geologic cross-sections, etc., in SubTask 6.4 below (Graphical Presentation of Data). SubteSfc;;||;;;. phas®-;;fi- f^l^^-'iV.' Subtasfe Wamar Data To Be EvaliHated ,X: ' ;.?.:.•-::;, 3.03 1 Cultural Resources Survey Findings Of Archeological And Hlstonc Surveys Conducted Within Study Area 3.02 1 Fracture Trace Analysis Location, Orientation. And Length Of Fracture Traces; Relation Of Fracture Traces To Known Faults And PSAs 3.09 I&ll Groundwater Elevations and Water Levels In Wells Located Throughout Study 3.11 Stream Flow Monitoring Area; Hydraulic Gradients; Groundwater Flow 3.15 Directions; Stream Flow Data 3.20 3.10 I&ll Geophysics Investigations Results From Geophysical Investigations; Locations 3.19 Of VLF Sun/ey 3.11 I&ll Drilling, Subsurface Sampling, Sampling Locations; Geologic And Hydrologic Data 3.20 and Well Installation 3.21 II Hydraulic Testing Bedrock And Overburden Pump Test Results; Location Of Pump Tests With Respect To PSAs And Receptors 3.22 II Dye Tracer Tests Dye Concentrations In Water Samples Collected At i Six Different Test Locations 3.05 1 Wetland Delineations Hydric Soil, Water Level, And Vegetation Data; Analytical Data From Samples Collected In Or Near m Wetlands; Location Of Wetland With Respect To PSAs ^W 300141 93 I hatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI-CO-02 * 3.23 II Ecological Sampling (II Recommended) Benthic Invertebrate And Fish Species Identification, Population Densities And Physica] Characteristics Of Area At Each Sample I Location 3.06 1 Surveys of Endangered Assessments of Potential Habitats; Results of Reld Species Habitat Sun/eys I 3.14 I&ll Surveying s Location And Elevation Of Soil Borings And Surface 3.24 Soil And Sediment Samples Using GPS; Elevation Of Wells Using Conventional Surveying. Accuracy Of I Survey Points I 6.4 Graphical Presentation of Data Map features of study areas, wetlands, geology, monitoring and potable well locations, I topography and streets will be incorporated into the GIS database. The following provides a summary of anticipated maps that will be generated in order to present data and information in the I RI Report: Site Location Map (including U.S. Census Tiger attributes where applicable) I Potable, Monitoring, and Industrial Well Location Map Soil Sample Location Map p Groundwater Sample Location Map Surface Water and Sediment Sample Location Map I Wetland Delineation Maps Groundwater Potentiometiric Surface Maps (4) I Contaminant Distribution Maps for Groundwater, Surface Soils, Subsurface Soils, I Soil Gas, Sti:eam Water, and Sti^eam Sediments Maps will be based on longitude and latitude coordinate system to maximize integration with the EPA and use of existing map images. Maps can be plotted from 8.5" x 11" to 24" x 36" in I either black and white or color depending on the nature and extent of the information presented. I 6.5 Phase II RI Groundwater Flow and Chemical Transport Modeling A regional groundwater flow model will be developed by USGS throughout the course of the RI/FS. Data generated by the Contractor is to be shared with EPA and USGS. Model output and data generated or collected by USGS will be shared with EPA and the Contractor throughout the I project. The purpose of the model will be to: P I 94 300142 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAtt 037-RI'C0-02 ° refine the conceptual understanding of: P D groundwater flow within and between the shallow unconsolidated glacial overburden aquifer and the underlying bedrock aquifer. D possible anisotropic flow behavior due to bedrock fracturing 0 groundwater/surface water interactions D contribution of groundwater recharge from the upland bedrock walls to the aquifer system, D zones of influence of large capacity pumping wells. ° evaluate potential paths of chemical migration o estimate approximate chemical migration travel times o assess the potential threat of contaminant migration to private and municipal water supply wells. ° consider remedial technologies which may be applicable for reducing groundwater contamination within the Pohatcong Valley. Site-specific fate and ti-ansport modeling will be conducted for the purpose of supporting the risk assessment, and for gaining a better understanding of the behavior of selected chemicals within the groundwater system. As part of the FS, the regional groundwater flow model will be used to assess remedial alternative options. The goals of the FS modeling will be to ascertain die adequacy of capture zones, estimate mass recovery rates of chemicals, and to predict cleanup times. Groundwater Flow Model As part of the regional groundwater flow model development, a conceptual model of the groundwater system will be developed. The system consists of an alluvium overburden above fractured limestone and dolomite. An evaluation will be performed to answer die following questions regarding the groundwater system: Can the fractured limestone be considered an equivalent porous media or does the groundwater flow model need to consider a dual porosity flow system? Are the valley bedrock walls contributing a significant groundwater flow component to the aquifer system, or can the bedrock walls be approximated as no-flow or low-flow boundaries? ^w 300143 95 ^^ Pohatcong Valley Groundwater Contaminati'on Site hAay 1999 Statement of Work WAtt 037-RI-C0-02 The first question listed above is very important. If the bedrock is highly fractured and cannot be modeled as an equivalent porous medium, then a dual porosity model, such as SWIFT/486 will be used, SWIFT/486 is a transient, fully three- dimensional model which simulates the flow and transport in porous and fractured geologic media. For simulation of fractured media, the model supports both dual- porosity and discrete fracture network conceptualizations. Migration within the rock matrix is characterized as a one-dimensional process. For the purposes of this SOW it is assumed that the bedrock can be modeled as an equivalent porous medium, and that the three-dimensional groundwater flow system will be modeled using MODFLOW (McDonald and Harbaugh, 1984) and flowlines will be evaluated using MODPATH (Pollock, 1989), The MODFLOW and MODPATH models are standard models for flow and particle tracking. They are among the most frequently used numerical codes in the groundwater profession and are endorsed and recommended by the International Groundwater Modeling Center and the EPA (1994), Pre- and post-processing will be performed using the Groundwater Modeling System (GMS). GMS was developed by the Engineering Computer Graphics Laboratory of Brigham Young University (Boss International and Brigham Young University, 1996). The recenUy released GMS software was developed under the direction of the U.S. Army Corps of Engineers and involves support from the Department of Defense, Department of Energy, and the EPA. GMS provides a comprehensive graphical (Windows) environment for numerical modeling, tools for site characterization, model conceptualization, mesh and grid generation, geostatistics, and sophisticated tools for graphical visualization and presentation of modeling results. Calibration and verification of the groundwater flow model will be conducted, and a sensitivity analysis performed. The calibration will be performed in order to arrive at estimates for model parameters which will reproduce field conditions. The model will be calibrated using the automatic calibration software PEST. PEST is a computer program for nonlinear parameter estimation of lumped or spatially distributed parameters. PEST updates die model's input file as part of the overall parameter estimation process. For optimization of parameter values, PEST employs a robust variant of the Gauss-Marquardt-Levenberg method of nonlinear parameter estimation. It runs the model as many times as it needs in order to find that parameter set for which the discrepancies between model-generated numbers and corresponding field-derived measurements are as small as possible in the weighted least squares sense. After calibration is completed, model verification will be performed in order to establish greater confidence in the model. During verification, the calibrated model is used to simulate a period in which conditions differ from the calibrated conditions. The sensitivity analysis is performed in order to establish the effect of parameter uncertainty on the calibrated model. Once the model has been calibrated and validated, a particle tracking run of the model will be conducted using MODPATH. "Particles" will be seeded at up to 15 different PSAs and their travel paths and travel velocities through the model domain will be calculated. 300144 96 Pohatcong Valley Gmundwater Contaminati'on Site May 1999 Statement of Work WAtt 037-RI-C0-02 Fate and Transport Modeling The particle tracking model will provide potential routes of chemical migration.- Particle tracking, by itself, however, does not provide estimates of chemical concentrations along a flowpath. During the RI, numerical and analytical chemical transport models will be used to estimate the spatial and temporal distribution of selected chemicals in groundwater. Analytical solutions (e.g., Fischer et al., 1979; Javandel et al., 1984) will be used, where applicable, to predict chemical transport. Analytical solutions are based on simplifying assumptions which may be applicable at some locations within the valley. Some conditions preclude the use of analytical solute transport models (e.g., irregularly shaped source distributions, multi-aquifer solute migration, complex flow conditions caused by aquifer heterogeneities, or extraction well networks). • Numerical models will be developed for three chemical constituents which occur most frequently and/or at the highest concentrations within the valley. The groundwater flow model will be used as the basis of transport. The numerical fate and transport model RT3D will be used to simulate chemical transport down the valley if solvent transport is found to be dominated by coupled degradation (as in the case of PCE, TCE, DCE and vinyl chloride. RT3D will be used. RT3D, recendy-released from Battelle National Laboratory, simulates 3-dimensional multi- species, reactive transport in groundwater. This model is based on the 1997 version of MT3D, but has several extended reaction capabilities. RT3D is also fully compatible with the pre/post-processing software GMS. Other transport codes (e.g., FRAC3DVS or SWIFr/486) will be considered for use if the fractured bedrock cannot be appropriately represented as an equivalent porous medium in the MODHLOW/RT3D code. Tetrachloroethene, trichloroethene, and benzene are currendy anticipated to be the three constituents for which numerical transport models will be developed. If a contaminant of greater magnitude or risk importance is detected during the RI, then the new constituent can be substituted for one of die diree listed above. For each d-ansport model, appropriate physical, geochemical, and biochemical parameters will be assigned to the models based on field information or reasonableestimate s obtained from scientific literature. The transport models will be regional and will have the same overall size and grid mesh dimensions as the flow model. The transport models will be calibrated by using contaminant distributions in 1984/1985 as the starting point and matching, as best as possible, die concentrations observed in the 1999 RI data. Thus, there are sets of data separated by time which will be used to calibrate the transport models. TASK 7 RISK ASSESSMENT ^^ 300145 Pohatcong Valley Gmundwater Contaminati'on Site May 1999 Statement of Work WAtt Q37-RI-C0-02 This task description presents the methodologies to be used in preparing the human health and ecological risk assessments (RAs) for the PVGCS site. The phased approach described in earlier I sections of this SOW will be used in a phased approach to the risk assessment. During Phase I, soil gas, soil boring, and groundwater samples will be collected. The results of the analyses will be used either to eliminate individual facilities (as PSAs) or provide the basis for a broader I investigation. Comparison of analytical results to risk-basedcriteri a will form die basis for decision-making. For Phase n, baseline risk assessments will be conducted at each of six individual facilities selected from those recommended for broader investigation. I The following sections of the SOW contain descriptions of Phase I and Phase n risk I assessment activities. I 7.1 Phase I -- Risk-Based Screening As described previously in this SOW, Phase I will include soil gas surveys. If VOCs or SVOCs arc detected in soil gas samples from a PSA, groundwater and soil boring samples will be I collected at the PSA and analyzed using EPA's CLP. The CLP data will be used in a risk-based decision making process that will, for each PSA, recommendeithe r broader investigation or elimination as a PSA. Criteria that will be used in the decision making process will include both I human health and ecological risk-based screening concentrations. The decision process is p described in the following paragraphs. I 7.LI Initial Screening - Soil Gas Suirvey I Soil Gas Survey data from each of the PSAs to be investigated are to be evaluated as follows: 1. If volatile or semivolatile organic compounds are not detected in soil gas samples, and there is little or no further reason for suspicion that contamination may be present at the facility; the I facility (or area of a facility if very large) will be recommended for elimination as a PSA, and soil I borings and groundwater sampling will not be conducted. 2. If volatile organic compounds are not detected in soil gas samples, but information pertaining to the facility gives continued reason for suspicion that contamination may be present at the I facility, soil borings and groundwater sampling will be conducted and results will be compared I with risk-based criteria, as described below. 3. If volatile organic compounds are detected in soil gas samples, soil borings and groundwater sampling will be conducted and results will be compared with risk-based criteria, as described I below. In addition, PSAs at which soil and groundwater sampling is conducted will also be p subject to a preliminary ecological evaluation, to determine whether potential ecological receptor 300146 I 98 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-O2 species and habitats could occur at the facility and be affected by site contamination. 7.U Risk-Based Screening - Human Health Direct Contact For PSAs at which soil boring samples are collected, results of analysis of samples from the 0 0 to 2 foot depth interval will be compared to EPA Soil Screening Levels (SSLs) for direct human contact using EPA Soil Screening Guidance: User's Guide (OSWER, Publication 9355.4-23, April 1996). The comparisons will be conducted using the following guidelines for making 0 decisions about disposition of the PSA: 1. If contaminant concentrations in these samples are determined to be greater than SSLs for direct human contact, the facility (or area of a facility if very large) will be recommended for broader scale investigations and an HHRA will be conducted at a later date; 2. If contaminant concentrations in these samples are determined not to be greater than SSLs for direct human contact, but information pertaining to the facility gives continued reason for suspicion that contamination may be present at the facility; the facility (or area of a facility if very large) will be earmarked for consideration of broader scale investigations and an e HHRA may be conducted at a later date; p If contaminant concentrations in these samples are determined not to be greater than SSLs for direct human contact, and there is no further reason for suspicion that contamination may be present at the facility; the facility (or area of a facility if very large) will be recommended for elimination as a Potential Source Area (PSA); Q 7.13. Risk-Based Screening - Human Health Impact to Groundwater 0 Analytical results for soil boring samples will also be compared to EPA SSLs for impact to groundwater. The comparisons will be conducted using the following guidelines for making Q decisions about disposition of the PSA: 1. If contaminant concentrations in these samples are determined to be greater than SSLs for impact to groundwater, the facility (or area of a facility if very large) will be recommended for broader scale investigations and an HHRA to be conducted at a later date; 0 If contaminant concentrations in these samples are determined not to be greater than SSLs for impact to groundwater, but information pertaining to the facility gives continued reason 99 300147 Q \1 I Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-O2 p for suspicion that contamination may be present at the facility; the facility (or area of a facility if very large) will be earmarked for consideration of broader scale investigations I and an HHRA may conducted at a later date; I 3. If contaminant concentrations in these samples are detennined not to be greater than SSLs for impact to groundwater, and there is no further reason for suspicion that contamination may be present at the facility; the facility (or area of a facility if very large) will be I recommended for elimination as a PSA; I 7.L4 Risk-Based Screening - Ecological Criteria I Analytical results for soil boring samples collected from the 0 to 2 foot depth interval will also be compared to the U.S. Department of Energy, Office of Environmental Management's Preliminary Remediation Goals (PRGs) for Ecological Endpoints (ES/ER/TM-162/R2), for I ecological impacts, with emphasis on terrestrial endpoints. The comparisons will be conducted using the following guidelines for making decisions about disposition of the PSA: I 1, If contaminant concentrations in these samples are determined to be greater than PRGs, the facility (or area of a facility, if very large) will be recommendedfo r broader scale ecological investigations and an ERA to be conducted at a later date; 2, If contaminant concentrations in these samples are determined not to be greater than PRGs, I but information pertaining to the facility gives continued reason for suspicion that contamination may be present at the facility; the facility (or area of a facility, if very large) will be earmarked for consideration of broader scale ecological investigations and an ERA I may be conducted at a later date; I If contaminant concentrations in these samples are determined not to be greater than PRGs, and there is no further reason for suspicion that contamination may be present at the I facility; the facility (or area of a facility, if very large) will be recommended for elimination as an area of ecological concern; I 7.1.5 Reporting Results - Risk-Based Screening I Following each facility investigation and evaluation of analytical data, the Contractor will submit a brief report to EPA, discussing comparison of data to SSLs and/or PRGs (as I appropriate), which will describe and justify fiuther investigation steps needed to delineate the p horizontal and vertical extent of identified contamination and to perform die HHRA and ERA, as 300148 I 100 0 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 necessary. Q 7,2 Phase H - Baseline Risk Assessments Quantitative HHRA and ERA will be conducted for PSAs that are found, as a result of Phase I a screening, to contain contamination greater than the SSL or PRG values discussed in the previous section. Maximum detected concentrations will be compared to these criteria. For planning purposes, the Contractor assumes that baseline HHRA and ERA will be conducted at six facilities, to be chosen based on Phase I results and in close consultation with EPA. 0 The Contiactor will perform the human health and ecological RAs for the PVGCS in compliance with the guidance promulgated under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended by the Superfund Amendments and Reauthorization Act (SARA) and the National Contingency Plan (NCP). In conducting the assessments, the Contractor will follow the procedures outhned in EPA's Interim Final Risk 0 Assessment Guidance for Superfund (RAGS)~Human Health Evaluation Manual (Part A) (EPA, 1989) RAGS Part D Standardized Planning, Reporting and Review of Superfund Risk Assessments (EPA, 1998), and Framework for Ecological Risk Assessment (EPA, 1992a). Other 0 resources that will be used when performing the RAs include: the Human Health Evaluation Manual, Supplemental Guidance: "Standard Default Exposure Factors" (EPA, 1991a), the Integrated Risk Information System (IRIS), the Health Effects Assessment Summary Tables f (HEAST), the Role of Baseline Risk Assessment in Superfund Remedy Selection Decision (EPA, 1991b), Calculating the Concenti-ation Term (EPA, 1992b), The Risk-Based Concentration Table H (EPA, 1997a), the Proposed Guidelines for Ecological Risk Assessment (EPA, 1996a), and U Ecological Risk Assessment Guidance for Superfund: Process for Designing and Conducting Ecological Risk Assessments (EPA, 1997b), 0 The following sections present brief descriptions of the technical scope of each risk assessment task. 0 7.2.1 Human Health Risk Assessment D The Human Health RA (HHRA) will consist of the following four main steps: selection of L chemicals of potential concern (COPCs); exposure assessment; toxicity assessment; and risk characterization. Each of these steps, in addition to an uncertainty analysis that presents "1 uncertainties associated with the HHRA, is discussed below in detail. w 7.2.1.1 Site Visit and Meeting Q f 300149 101 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-O2 4 The Contractor's Risk Assessment Specialist will participate in one site visit/meeting with EPA during the RI to become familiar with the environmental setting of the site and its demographics. 7.2.1.2 Data Collection and Evaluation The first step in the HHRA will be to review Phase I and n analytical results to be used in the quantitative assessment in order to select chemicals for evaluation. The HHRA for the PVGCS will be based on both Phase I and n. Analytical data provided by the on-site and off-site laboratories will be quantitatively evaluated in the HHRA. Other analytical data collected during previous investigations will not likely be used in the HHRA, as these data are much older and likely do not reflect current groundwater conditions. Factors considered in evaluating the data and selecting COPCs for evaluation in the HHRA include an evaluation of data validation results; a comparison of site concentrations to human health-based screening levels; and the relationship of the detected chemical concentrations to site-specific background or upgradient concentrations (EPA, 1989). The methodologies to conduct these screenings are described below. # Samples collected during both Phase I and Phase II field investigations will be analyzed by EPA's CLP. It is assumed that the Contractor will be provided with analytical results that have been validated according to EPA Region II's data validation procedures, which includes comparison to and appropriate qualifications based on laboratory, rinse, and trip blank concentration data. Rejected (i.e., R-qualified) data will not be used in the risk assessment. All chemicals that are not rejected or are not determined to be sampling or laboratory artifacts will be carried through the following screening process. Prior to selecting COPCs, the sampling data will be summarized by frequency of detection, range of detected concentrations, arithmetic mean concentrations, range of background concentrations, and risk-based screening values for each environmental medium (i.e., groundwater, surface soil, subsurface soil, surface water, sediment). The summaries will be presented in RAGS D format tables. In addition, the data collected from each medium will be grouped, in order to reflect different patterns in exposure conditions and COPC distribution at the site. Preliminary data groupings, which are subject to change upon thorough review of the sampling data and further investigation on the site, have been developed based on currently available information. It should be noted that the ecological risk assessment (ERA) may evaluate different data groupings; the methodologies for conducting the ERA are discussed in the ecological risk assessment section above. ^F 300150 102 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 P Groundwater Groundwater analytical data from private wells located near PSAs will be evaluated individually, whereas groundwater analytical data may be combined into a maximum of four data groupings, including one PSA site-wide grouping that includes data from the entire PSA that are defined in the RI. Because the overburden and bedrock aquifers are believed to be connected, samples from the two aquifers are likely to be grouped together for the purposes of the HHRA, Surface Soil and Subsurface Soil Surface soil and subsurface soil analytical data for each of the six PSAs will be separately grouped to be consistent with exposure scenarios that are reasonable for the individual PSA. Surface and subsurface soil data may each be grouped site-wide or divided into sub-groupings, depending on PSA-specific circumstances. i Surface Water and Sediment Analytical data for both surface water and sediment will be considered at each of the six PSAs, as appropriate. PSA-specific groupings may be made if more than one drainage area is impacted by surface water/sediment from the PSA, P The next step of the chemical selection process, which applies only to the HHRA, will be to compare exposure point concentration of chemicals detected in each of the groupings to the most recent EPA Region in risk-based concentrations (RBCs). These concentrations are presented in Tables 2-3 dirough 2-8. Because the site includes rural, residential, and industiial areas, residential RBCs will be used as a conservative screening method. See Receptor Characterization for a discussion regarding current and potential future receptors at the PVGCS). Residential RBCs are human health-protective chemical concentrations that are back-calculated using EPA-approved toxicity criteria, a 1x10-6 target risk level or a 1.0 hazard index, and conservative residential exposure parameters. A hazard index of 0.1, instead of 1.0, will be used to ensiure that compounds that could combine to result in a hazard index greater than 1,0 will not be eliminated from the evaluation. Soil and sediment concentrations will be compared to residential soil RBCs, while groundwater and surface water concentrations will be compared to tap water RBCs, Using tap water RBCs for the surface water screening is considered to be conservative, since surface water in the study area is not used for drinking water purposes. If no screening concentration is available for a chemical detected in a medium, one may be back-calculated using an appropriate toxicity criterion and the same conservative exposure assumptions used in developing odier screening concenti-ations. If the exposure point concentiations of chemicals in die evaluated groupings are less than their respective RBCs, the probability of developing cancer would be less than one in one million, and adverse noncarcinogenic effects would not be expected to occur. ^^ 300151 103 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 Therefore, all chemicals that are present at concentrations lower than their respective RBCs (or I other screening concentrations) will be eliminated as COPCs, RBCs are.not available for lead, since no toxicity criteria exist for this chemical. Therefore, other available lead screening criteria will be used instead of RBCs for the purposes of screening lead in the HHRA. For sediment and soil, the residential soil screening level of 400 mg/kg (EPA, 1994) will be used, while for surface water and groundwater, the lead action level of 15 mg/L (EPA, 1996b) will be used. Geochemical major elements (aluminum, calcium, iron, magnesium, potassium, and sodium) make up more than one percent of the earth's crust and are, with the arguable exception of aluminum, essential human nutrients. Unless there is information that indicates that one of the major elements should be considered a COPC at a PSA, they will not be included in the risk assessment. The next step of the chemical selection process applies to those inorganic chemicals that are not screened out when compared to RBCs, If an adequate number of site and background samples is available, the following statistical comparisons between site and background concentrations will be conducted to determine whether site inorganic chemical concentrations are within background levels and can be eliminated from further evaluation. The site and background p data will first be tested using the Shapiro-Wilks test to determine the distribution type of the data sets. For normally or log-normally distributed data, a two-tailed variance ratio test (the F test) will be performed to determine if the variances of the on-site and background data sets are similar. If the variances for the two data sets are found to be similar, then the one-tailed pooled variance t-test is considered appropriate to test for similarity between on-site and background levels. If on-site and background variances are found to differ significanUy, or if the data are determined to be neither normally nor log-normally distributed, then a nonparametric test (the one-tailed Mann-Whitney test) will be used to test for sinodlarity between on-site and background levels. All statistical tests will be performed using a significance level of 95% (alpha = 0.05) and are described in detail by Zar (1984). Statistical tests for log-normally distributed data will be performed using natural log-transformed monitoring data. Those inorganic compounds that are considered to be statistically within background levels will be eliminated from further consideration. If too few site and background samples are available, the mean on-site chemical concentration in the particular medium will be compared to the mean background concentration. If a site-related chemical's mean concentration exceeds two times the mean background concentrations, the chemical will be retained as COPCs. Tentatively identified compounds (TICs) will not be carried through the quantitative assessment, due to the uncertainty surrounding their positive identification and quantification. However, TICs will be summarized, and the ranges of their concentrations will be presented in the HHRA and their presence will be discussed qualitatively. p 300152 I 104 Pohatcong Valley Gmundwater Contaminati'on Site May 1999 Statement of Work WAM 037-RI-C0-02 P As regional contamination of groundwater is the primary focus of investigation at the PVGCS, a quantitative risk assessment of groundwater analytical data will be conducted on a site-wide basis as well as at specific PSAs. 7.2.1.3 Quantitative Evaluation The first step of the quantitative HHRA is the exposure assessment, where the route, frequency, duration, and magnitude of exposure to COPCs in the PVGCS groundwater are characterized. Two overall exposure conditions will be evaluated. The Current Land-Use Condition will evaluate the potential for exposures associated with the site as it currently exists, while the Future Land-Use Condition will evaluate the potential for exposures under future land-use conditions, assuming no remedial action is taken (i.e., the no-action alternative) at the site. The exposure assessment will be conducted in a series of three steps: 1) receptor characterization; 2) exposure pathway identification; and 3) exposure quantification. Receptor Characterization As the first step of the groundwater exposure assessment, potentially exposed populations (receptors) are identified and described with respect to those characteristics that influence P exposure. Factors such as activity patterns in the area, as well as source characteristics and routes of transport for the COPCs, are considered when identifying potentially exposed populations. The PVGCS is located in the Pohatcong Valley, which extends from northeast of the Borough of Washington to the Delaware River in Warren County. The northern and southern boundaries of the study area are delineated by the bases of the Oxford and Pohatcong mountains, which border the valley. The site includes rural, industrial, and municipal land. Under current land-use conditions, the receptors at or in the vicinity of the PVGCS are likely to be individuals residing in the study area, as well as workers working at PSAs and other businesses in the area. Because groundwater from private residential wells is currendy being used in the study area, receptors under current land-use conditions are contacting groundwater and likely being exposed to COPCs. Under future land-use conditions, the site will likely remain in its current land-use status. Therefore potential future receptors to contamination in groundwater include workers and residents. 300153 105 I Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-CO-02 p Exposure Pathway Identification I As the second step of the exposure assessment, exposure pathways associated with receptors at the PVGCS are identified based on consideration of the sources, releases, types and locations of chemicals, and the location and activities of receptor populations. Each exposure pathway I includes: 1) a source and mechanism of release; 2) an environmental transport medium; 3) a point of potential exposure with the contaminated medium; and 4) a route of exposure (e.g., ingestion of groundwater) at the exposure point. Those pathways that contain each of these elements are complete and are considered for quantitative evaluation. The most important pathways (i.e., those typically associated with the greatest human health risks) through which individuals may be exposed to chemicals originating from the PVGCS will be quantitatively evaluated in the HHRA. The output of this task will be a prediction of the potential magnitude, frequency, and duration of chemical exposures through the identified exposure pathways. A discussion on the potential exposure pathways under current and future land-use conditions follows. 7.2.1.4 Current Land-Use Conditions Under current land-use conditions, treated groundwater from die PVGCS is being used for the municipal water supply. However, since this water is treated prior to use and is tested on a regular basis, individuals who consume this groundwater are not exposed to COPCs associated with the site. In addition, there are individuals who have private wells that are not connected to the municipal water supply; these individuals are currently contacting groundwater and are likely exposed to COPCs associated with the PVGCS. As a result, the risk assessment will evaluate risks associated with individuals exposed to groundwater from each of the private wells that are sampled during the RI. Individuals could be exposed to chemicals in private well groundwater primarily via ingestion; therefore, child and adult ingestion exposures will be evaluated in the risk assessment. In addition, residents could be exposed to COPCs in groundwater via dermal absorption while washing or bathing, thus this pathway also will be evaluated for child and adult residents. Finally, residents also could be exposed via inhalation of VOCs while showering; this pathway will be evaluated only for adult residents, who are mostly Ukely to shower. In summary, the following pathways will be considered for evaluation under current land-use conditions for each of the sampled private wells: Ingestion of groundwater by child and adult residents; Dermal absorption of chemicals in groundwater while bathing by child and adult p residents; and 300154 I 106 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-(^ ^0 ° Inhalation of volatile organic compounds (VOCs) released from groundwater while ^^ showering by adult residents. Current land uses at each of the six PSAs to be evaluated are likely to vary. Industrial exposure pathways are likely to exist at most of them, and residential pathways may be present on or near each PSA. Current land use conditions will be evaluated in each of the PSA-specific risk assessments, and applicable exposure pathways will be evaluated for each facility, n 7.2.1.5 Future Land-Use Conditions As noted earlier, land-use at the site is likely to remain in its current residential, rural, and industrial land-use status. Since groundwater in the Pohatcong Valley is being used currently, it is likely that it will continue to be an important water supply source in the future. Therefore, exposures to both future workers and residents will be addressed for future land-use conditions, as described below, assuming no remedial action is taken to treat the groundwater. • Exposures of workers to chemicals in groundwater via ingestion will be considered under future land-use conditions. As discussed previously, several different plumes of contamination pj will be evaluated in the PVGCS site-wide groundwater HHRA; accordingly, ingestion exposures ^ will be evaluated for all the monitoring well data groupings. Although dermal exposures also ^^ could occur (while washing hands, for example), the exposed body surface area would be Wm relatively small (hands and lowbr arms) and exposures would be infrequent. Thus, dermal ^^ exposures to groundwater by a worker will not be evaluated in the site-wide groundwater HHRA. Under future land-use conditions, hypothetical future child and adult residents could be exposed to chemicals in groundwater, primarily via ingestion of water used for drinking. Therefore, this exposure pathway will be evaluated for all the monitoring well data groupings evaluated in the site-wide groundwater HHRA. Additionally, inhalation of dissolved VOCs released into indoor air while showering will be evaluated for adults, while dermal exposures while washing or bathing will be evaluated for both children and adults. This is a more conservative approach for homeowners than modeling air vapor phase transport through soil and found foundation materials. In summary, the following pathways will be considered for evaluation in the site-wide groundwater HHRA under future land-use conditions for each of the monitoring well data groupings: R " Ingestion of groundwater by site workers; ° Ingestion of groundwater by future child and adult residents; ° Inhalation of volatile organic compounds (VOCs) released from groundwater while ^m 300155 107 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 4 showering by future adult residents; and ° Dermal absorption of chemicals in groundwater while bathing by future child and adult residents. Because the six PSAs that will be subject to facility-specific HHRAs have not yet been identified, future land use conditions can not yet be determined. They are likely to be similar to current uses, a mix of rural, residential, and industrial. Future land use conditions will be evaluated in each of the PSA-specific risk assessments, and applicable exposure pathways will be evaluated for each facility. ExjX)sure Quantification For each exposure pathway selected for quantitative evaluation, concentrations at the exposure points will be determined using data collected during the RI. In accordance with EPA (1992b), a minimum of 10 samples is required in order to calculate a 95% upper confidence limit (UCL) concentration. If at least 10 samples are available, the data set will be tested using the Shapiro-Wilks test of normality (Gilbert, 1987) to determine whether the data fit a normal or lognormal distribution, and the 95% UCL based on the appropriate distribution type will be used. The 95% UCL chemical concentrations for a given medium will be calculated by averaging the detected concentrations with one-half the detection limit of the non-detects. One-half the P detection limit is typically used in risk assessments (EPA, 1989) when averaging non-detect concentrations because the actual value can be between zero and a value just below the detection limit. In addition, data from duplicate samples will be averaged together and treated as one result. In accordance with EPA (1989) guidance, the reasonable maximum exposure (RME) exposure point concenti:ations used in the quantitative HHRA will be the 95% UCL on the arithmetic mean, or the maximum detected concentration in a given medium/data grouping, whichever is less. In addition, if fewer than 10 samples are available, a 95% UCL concentration will not be calculated, and the exposure point concentration will be equal to the maximum detected value. Since VOCs in groundwater are of particular concern at the PVGCS, the inhalation of VOCs while showering will be evaluated, as described above. Exposure point concentrations in shower room air as a result of the release of VOCs from groundwater will be determined using the shower model developed by Foster and Chrostowski (1987), Using the shower model, inhalation exposures will be modeled by estimating the rate of chemical release into the air (generation rate), die buildup (shower on) and decay (shower off) of VOCs in shower room air, and the resulting time-weighted average VOC concentrations for the duration of shower room exposure. Potential indoor air health threats will be evaluated for residential receptors using results of modeling of migration of VOCs from groundwater and soil into residentialbasemen t air. Next, for all chemicals except lead, exposures will be quantified for each receptor population by calculating lifetime average daily doses (LADDs) for exposure to chemical carcinogens and average daily doses (ADDs) for exposure to noncarcinogenic chemicals, following EPA (1989, 300156 108 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-CO-02 1992c) guidance. LADDs and ADDs will be based on the exposure point concentrations and p assumptions regarding the frequency and duration of exposures, and the rate of intake (e.g., quantity of groundwater ingested). In accordance with EPA (1989,1992c) guidance, exposures will be quantified assuming a RME scenario. Dermal absorption of chemicals will be quantitatively evaluated following EPA (1992d) guidance for dermal exposure assessment. Potential exposures to lead will not be evaluated using the LADD/ADD methodologies (see below); thus, this section will not provide quantitative estimates of lead exposures. For PSAs at which lead is found to be a COPC, blood lead concentrations will be estimated for appropriate receptors (child or adult) using EPA's Integrated Exposure Uptake/Biokinetic Lead Model. 7.2.1.6 Toxicity Assessment and Documentation ™ The COPCs in groundwater will be characterized with respect to their toxic effects in humans, 8 aqd relevant critical toxicity criteria will be identified for each chemical. Two types of dose-response toxicity criteria are used for the human healdi assessment: EPA-derived cancer S slope factors (CSFs) for potentially carcinogenic chemicals; and reference concentrations and ® reference doses (RfCs/RfDs) for chemicals exhibiting noncarcinogenic effects. For carcinogens, ^^ the chemicals' weight-of-evidence classifications for human carcinogenicity will be provided and ^B discussed. For noncarcinogens, uncertainty factors used in deriving the RfCs/RfDs will be ^^ provided, along with toxicity information such as target organs and effects endpoints. The primary source of the toxicity criteria will be, in order of preference, EPA's IRIS and HEAST databases. In addition, other sources of toxicity criteria include the National Center for H Environmental Assessment (NCEA), and values obtained from the Region in RBC table (EPA ® 1997a), and open literature. In order to evaluate potential risks associated with dermal absorption exposures, oral toxicity criteria will be adjusted using absolute oral absorption factors obtained from Agency for Toxic H Substances and Disease Registry (ATSDR) Toxicological Profiles or toxicological literature. In — cases where chemical-specific absolute oral absorption factors are not available, a default oral absorption value of 1.0 will be used in the HHRA. B Because no dose-response toxicity criteria exist for lead, the HHRA cannot quantitatively H evaluate lead doses for potential receptors. Instead, an alternative methodology will be used for * determining adverse effects associated with potential lead exposures evaluated in the assessment. In order to assess ingestion exposures to lead, concentrations in blood will be estimated using § EPA's Biokinetic Update Model. ^W 300157 109 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 4 7.2,1,7 Risk Characterization Potential human health effects associated with exposures to in contaminated media will be characterized by combining estimated exposures (LADDs and ADDs) with appropriate EPA dose- response criteria. The results of the risk characterization will include estimates of the upper-bound individual cancer risk estimates for potential carcinogens and a hazard index for noncarcinogens. The individual lifetime excess cancer risk for a chemical exhibiting carcinogenic effects will be calculated by multiplying the upper-bound cancer slope factor by the estimated LADD averaged over 70 years. In addition, if risks exceed the 1x10-2 risk level, the one-hit cancer risk equation will be used. For noncarcinogens, potential adverse effects will be calculated by means of a hazard index technique, in which the ADD is divided by the RfD, as recommended by EPA (1989). Risks for each evaluated media will be estimated by combining risks associated with individual chemicals to allow for the cumulative assessment of chemicals A hazard index greater than a threshold level of 1.0 will trigger a detailed evaluation, in which hazard indices for groups of chemicals affecting similar target organs will be calculated. If a target organ-specific hazard index exceeds 1.0, there may be concern for potential health effects (EPA, 1989). 7.2.1.8 Qualitative Evaluation of Chemicals Without Toxicity Criteria Quantitative characterization of potential risks and hazards will be made for chemicals with P toxicity criteria available from generally accepted sources (IRIS, HEAST, etc.). Some chemicals selected as COPCs, however, may not have toxicity information available. For these cases, a qualitative estimation of the contribution the presence of these chemicals as COPCs to overall risk will be evaluated qualitatively. The qualitative discussion will include evaluation of lead and of any TICs reported. 7.2.1.9 Discussion of Uncertainties The uncertainty section of the HHRA will provide a discussion of the major sources of uncertainty associated with the risk assessment. This review will consider important uncertainties associated with selection of chemicals of potential concern, toxicological data and models, and exposure and dose estimation. Central tendency estimates of risk will be provided in the certainty analysis of the HHRA. The purpose of this discussion is to support interpretation of the HHRA assessment results and understanding of the most important factors affecting the estimates of potential adverse effects on human health. 7.2.2 Ecological Risk Assessment P 7.2.2.1 Preliminary Remediation Goals 300158 110 4 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 Soil preliminary remediation goals will be calculated for any contaminant that exceeds a Hazard Quotient of one. Q National and regional EPA guidance for evaluating ecological risks at hazardous waste sites 0 (EPA 1992a, 1996a, 1997b) recommends a phased approach to ecological risk assessment Conceptually, the screening phase is the planning and scoping phase, culminating in the presentation of the ecological conceptual site model, identification of objectives and scope of the B ERA, and identification of specific ecological resources selected for evaluation in the ERA. As specified by EPA, Phase I of the PVGCS investigation includes two of the three elements of a "ti^ditional" screening-level ERA: D A preliminary evaluation of potential ecological receptor species and habitats is Q planned for those PSAs at which soil borings and groundwater sampling is required, and Results of analysis of PSA soil samples will be compared to ecological PRGs to determine whether risk-based ecological screening criteria are exceeded. The third element that is often included in a more traditional ERA, a site-specific ecological t conceptual model, will be formulated, if appropriate, for each of the six specific PSAs subject to Phase II investigations. The PSA-specific ERAs to be conducted during Phase n will be conducted as described in the following paragraphs. The ERA is planned as a phased effort. The proposed phased process Q encompasses the spirit of the ERAGS process, although not exactiy the letter or order of ERAGS. The variances between the planned effort and the standard ERAGS process reflect the nature of the PVGCS, which is defined by area-wide groundwater contamination. Q 7.2.2.2 Problem Formulation i The problem formulation section of the ERA includes a description of the habitats and j-, potential ecological resources associated with the site; an identification of the COPCs at the PVGCS and the potential exposure pathways by which ecological resources could be exposed to these chemicals; and a description of the organisms, populations, or communities most likely to r-i be adversely affected by these chemicals. The following sections provide a more detailed description of each step of the problem formulation process. 0 7.2.2.3 Site Characterization f Ill 300159 I 4 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 The first step in the problem formulation process is site characterization. The objectives of the site characterization are twofold: to initially identify and characterize die habitats and ecological receptors occurring at the PVGCS; and to preliminarily describe the nature and extent of chemical contamination at the PVGCS based on available information. These steps will be performed during Phase I, as described in sub task 9.1. A site walk will be conducted by an ecologist as part of the site characterization to qualitatively identify the on-site aquatic and terrestrial habitats, to identify wildlife species that occur or are likely to occur (based on habitat composition) in the Pohatcong Valley, and to identify any observable adverse effects on ecological receptors. This information aids in the selection of potential ecological receptors and contaminant pathways for the Phase II, PSA-specific ERA. In addition to the site walk, information about local terrestrial and aquatic resources will be gathered from maps of the study area, from aerial photographs, and from available reports describing the area by the U.S. Fish and Wildlife Service, by State agencies with responsibility for natural resources, and from available scientific literature. Federal and State agencies also will be contacted for information on 4 threatened or endangered species and critical or protected habitats in the Pohatcong Valley. In addition to a description of the ecological receptors occurring at Pohatcong Valley, the site characterization section will describe the likely release, migration, and fate of chemicals associated with the site and identify, in general terms, ecological resources that could be adversely affected by these chemicals. This information will be summarized in the ecological conceptual site model for die PVGCS. 7,2.2.4 Identification of Chemicals of Potential Ecological Concern This section of the ERA will identify COPCs selected for detailed evaluation in the PSA- specific ERAs. COPCs will be identified based on data collected during the Phase I and II. The purpose of selecting COPCs is to identify chemicals that are present because of past activities at the site and that have the potential to adversely affect ecological receptors. Based on historical sampling data for groundwater, VOCs, particularly TCE and PCE, are most likely COPCs. Other previously detected VOC contaminants in groundwater include: carbon tetrachloride; 1,2-DCE; 1,1,1-TCA; 1,1,2-TCA, 1,3-dichlorobenzene; chloroform; 1,1-DCA; methylene chloride; and vinyl chloride, and BTEX compounds. Some semivolatile organic compounds (SVOCs), including bis(2-ethylhexyl)phthalate and di-n-octyl phthalate, have also been detected in groundwater in die PVGCS study area. p 300160 I 112 D Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 The same general procedure used for the Human Health Risk Assessment (HHRA) will be P used to identify COPCs for evaluation in the screening-level ERA. However, human-health-based toxicity screening values recommended in EPAGS will be used for the 0 identification of COPCs in the ERA. Ecologically-based toxicity screening values, such as chronic ambient water quality criteria (AWQCs; EPA, 1986; 1995a), sediment quality criteria (SQCs; EPA, 1993), sediment quality benchmarks (SQBs; EPA 1995b; 1996c) or values from die D published literature (Smidi et al., 1996; Suter and Tsao, 1996). For the PSA-specific ERAs, exposure point concentrations of detected chemical will be compared to the ecologically-based toxicity screening values. If the exposure point concentration is less than the screening value, the ,Q chemical will be eliminated as a COPC. In addition to identification of the COPCs, the data groupings selected for evaluation in the ERA will be summarized in this section of the ERA along with a summary of the detected concentrations of the COPCs to be evaluated. Data groupings 0 will be used in each medium to reflect different patterns in exposure conditions and COPC distribution at the site. 7.2.2.5 Identification of Exposure Pathways and Potential Receptors for Analysis 0 In this section of the ERA, the potential transport and exposure pathways for the ecological receptors and the COPCs at the PVGCS as a whole will be identified and discussed. Pathways 0 and receptors for individual PSAs will be identified in detail during Phase II. This discussion will also include the ecological species (i.e., receptors) that could be adversely affected by these chemicals. Transport and exposure pathways will be identified based on consideration of: the source/mechanism of chemical release; the medium (or media) of chemical transport; and the route of exposure at the contact point. 0 Potential receptors will be identified based on the type and extent of available habitat and the 0 extent, magnitude, and location of potential chemical contamination. 0 Based on available information about the PVGCS, the most likely complete site-wide transport and exposure pathway is the movement of groundwater to a downgradient groundwater-surface water interface within adjacent aquatic habitats, such as streams. The two primary streams associated with the PVGCS are Pohatcong Creek and Shabbecong Creek. In addition, there are a number of wetlands associated with these two streams. Within these habitats, potential exposure media would be sediments and surface water. Potential receptor species are 0 either fish or macroinvertebrates that are found in these streams. Aquatic receptors in these streams may be exposed to COPCs by ingestion of surface water, sediment, and food containing COPCs. Current information is insufficient to the performance of PVGCS-wide ecological risks. 0 The focus of Phase H, therefore, will be PSA-specific. t ^^^ 300161 D I 4 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-CO-02 Surface soil could be an exposure medium in the vicinity of specific source areas, and terrestrial plants may be exposed via direct contact and soil invertebrates via direct contact and ingestion of soil. These pathways will be evaluated in the PSA-specific ERAs, as appropriate. Terrestrial wildlife, such as birds and mammals, could be exposed to COPCs in media through a variety of potential exposure pathways including the ingestion of surface water, the ingestion of food (e.g., plants, soil invertebrates, fish) that have accumulated chemicals, and the incidental ingestion of surface soil and sediments while foraging or grooming. Other exposure pathways for terrestrial wildlife, including exposure via dermal contact with surface soil, surface water, and sediment, will be considered. The most likely exposure pathway for terrestrial wildlife at the PVGCS is the ingestion of surface water or sediment, because VOCs do not bioaccumulate and exposure via the foodchain is unlikely. Based on the identification of the COPCs and potential exposure pathways, representative receptor species or species groups will be selected for evaluation in the PSA-specific ERAs. As discussed previously, the PVGCS is likely to support a variety of plant and animal species diat could be adversely affected by COPCs in various environmental media. A list of potential receptor species/species groups to be used as indicators of the potential for adverse effects will be developed. Based on currendy available information, the following species/species groups may be considered for quantitative or qualitative evaluation in the ERA. P Receptor species or species groups may be added or removed from the evaluation, if warranted, based on the data collected during this RI. Terrestiial Plants - Terrestrial plants have intimate contact with surface soils and would be exposed to COPCs in surface soils. Aquatic plants - Aquatic plants may be in contact with surface waters that have been contaminated with COPCs. Soil Invertebrates - Soil invertebrates are direcdy exposed to and often ingest surface soil and would be exposed to COPCs in surface soils. In particular, earthworms are in intimate contact with and ingest large amounts of surface soil, and would be exposed to COPCs in surface soils. Terrestiial Wildlife - A variety of terrestrial wildlife are likely to occur in the PVGCS and may be exposed to COPCs via the ingestion of food, surface soil, surface water, and sediment. Among these potential exposure pathways, the ingestion of COPCs in surface water and sediment is likely to be the most significant potential exposure pathway. Specific terrestrial wildlife will be selected based on observations during the site visit. Fish and Macroinvertebrates - As already discussed, die streams and wetlands within the PVGCS are likely to support both fish and aquatic macroinvertebrates. Aquatic P receptors could be exposed to COPCs in surface water and sediment, and via the I 114 300162 Q Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 ingestion of COPCs in food. P The above list provides an overview of the species or species groups that may be considered Q for evaluation in the ERA. However, this list should be considered preliminary and is likely to be revised based on the results of the site characterization and the COPCs identified in various environmental media. 0 7.2.2.6 Identification of the Assessment and Measurement Endpoints and of the Assessment 0 Scope and Objectives D The potential for adverse effects to ecological receptors is dependent on the ecological receptor species present at the site, the pathways by which the ecological receptors may be exposed to COPCs, and the mode of action of the COPCs. Once defined, the assessment and D measurement endpoints and the scope and objectives of the ERA will be identified. D Assessment endpoints are defined as the ecological effects that drive the decision making process regarding the need for further investigation and/or remediation (Suter, 1993). Measurement endpoints are the methods or means by which the assessment endpoints are 0 approximated or represented (Suter, 1993). Measurement endpoints are generally surrogates for assessment endpoints and are necessary because, in most cases, assessment endpoints cannot be directly measured or observed. Accordingly, measurement endpoints are generally the field and/or laboratory methods used to evaluate the assessment endpoints. However, the specific assessment and measurement endpoints for the ERA cannot be identified until both the COPCs and the potential receptor species have been identified based on the results of the site D characterization. The specific objectives and scope of the ERA will be identified following the identification of the measurement and assessment endpoints. D 7.2.2.7 Exposure Characterization In the exposure assessment, the concentration and/or dose of the COPC to which a receptor species could be exposed is identified. For each exposure pathway selected for quantitative evaluation, concentrations at the exposure point will be estimated, and die receptor-specific exposure will be quantified. Exposure point concentrations will be estimated using environmental sampling data either alone or in conjunction with environmental fate and transport models. D For terrestiial plants, soil invertebrates, and bendiic-dwelling aquatic life, the maximum 0 concentration level of the chemical concentration measured in surface soil or sediment will be used to evaluate exposure. Q f 115 300163 D Pohatcong Valley Groundwater Contaminati'on Site May 1999 Statement of Work WAM 037-RI-C0-02 4 As discussed previously, terrestrial wildlife species may be exposed to COPCs through a variety of pathways including the ingestion of surface water, ingestion of plants and animal prey, 0 and incidental ingestion of surface soil and sediments while foraging and grooming. Exposures of predators to these chemicals in potential prey will be assessed if chemicals that accumulate are detected in the abiotic media (e.g., soil, sediment, surface water). However, because VOCs are the primary focus of this investigation, foodchain effects are not expected. Instead, terrestrial wildlife exposure to VOCs in surface water and sediment via ingestion will be evaluated. In the event that chemicals of bioaccumulative concern are detected, exposures to birds and mammals may be quantified by estimating the total daily dose (in mg/kg body weight) for the selected receptors. The specific model used to quantify potential exposures will depend on the a specific receptor species and exposure pathways evaluated. If an ERA is determined to be appropriate, the Contractor shall develop an following exposure model to be used to estimate the total daily dose of a chemical that a terrestrial predator would receive from the ingestion of a potential prey item. Q Chemical concentration in a particular food item will be estimated by multiplying biocOncentration factors (BCFs) or bioaccumulation factors (BAFs), whichever is applicable, Q obtained from the scientific literature by the chemical concentrations measured in die abiotic media to which the food item is exposed. The mean chemical concentration will be used because it most accurately reflects the concentration to which most potential predator species would be exposed while foraging. Factors such as habitat, food preference, and home range as described in P the available literature will be used to estimate exposure. Analogous equations may be used to determine the ingestion of chemicals from sediment and Q surface water for the estimation of the total dose of a chemical that a terrestrial receptor species might receive (via ingestion) from the environment. Chemical concentrations measured in Q sediment and surface water will be used to evaluate these potential exposure pathways. D 7.2.2,8 Ecotoxicological Effects Assessment In the ecotoxicologic effects assessment, the toxicity of die COPCs to terrestrial and aquatic organisms is characterized with respect to terrestrial and/or aquatic organisms. Relevant toxicity data will be summarized for the selected receptor species, and the toxicity values to be used in the evaluation of die potential for adverse effects will be derived. An outline of the procedures that will be used to generate toxicity values for the evaluation of potential adverse effects to terrestrial and aquatic species is summarized below. 0 7.2.2.9 Toxicity to Terrestrial Organisms D Toxicity criteria have not been developed by EPA for terrestrial species. Consequentiy, 116 300164 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-CO-02 toxicity data in the scientific literature will be reviewedt o characterize the toxicity of the COPCs in surface soils. The discussion that follows describes examples of some of the method s that will be used should terrestrial species be identified in the PSA-specific ERA in Phase n. For example, the evaluation of potential adverse effects to plants and earthworms, if i necessary, will be based on estimates of the concentration of a chemical in soil at which no adverse effects are likely to occur to the ecological receptor. Where available, chemical concentrations reported by Will and Suter (1994a) to be protective of terrestrial plants and chemical concentrations reported by Will and Suter (1994b) to be protective of earthworms will be used. In the absence of these values, toxicity values will be derived based on No-Observed-Adverse-Effects-Concentrations (NOAECs) or Lowest-Observed-Adverse-Effects-Concentrations (LOAECs) found in the scientific literature. For the evaluation of the potential for adverse effects to birds and mammals, toxicity values conceptually similar to human health RfDs will be developed. Toxicity criteria to be developed will estimate the dose of a chemical at which no adverse effects are likely to occur in the selected receptor species. Where available, dietary No-Observed-Adverse-Effect Levels (NOAELs) m reported in Opresko, et al. (1994) will be used to evaluate the potential for adverse effects to terrestrial wildlife. In the absence of these values, toxicity values will be derived based on the highest NOAELs found in the scientific literature. If a NOAEL is not available for a chemical, a Lowest-Observed-Adverse- Effect Level (LOAEL) or LC50 will be used, and uncertainty factors will be applied to estimate a NOAEL. 7.2.2.10 Toxicity to Aquatic Organisms Federal Ambient Water Quality Criteria (AWQC) available New Jersey Surface Water Quality Criteria derived for the protection of aquatic life will be used to evaluate the potential for adverse effects to aquatic life from the COPCs in surface water. Both acute and chronic criteria will be used in the assessment. If a criterion has not been developed for a COPC, the available Lowest-Observed-Effect Concentrations (LOECs) reported by the EPA will be used. In the absence of LOECs, Tier n values from Suter and Tsao (1996) will be used. EPA Sediment Quality Criteria (SQC; EPA 1993); EPA Region UIBTAG Screening Levels for Sediments and Sediment Quality Benchmarks (SQBs; 1996c); NTOEP Sediment Guidance (Draft Guidance for Sediment Quality Evaluations, NJDEP, 1991; and Present Use of Draft 1991 NJDEP Guidance for Sediment Quality Evaluations, (October 1997 Update); and The Ontario Guidelines (D. Persaul, et al, August 1993, "Guidelines for the Protection and Management of Aquatic Sediment Quality in Ontario," Ontario Ministry of Environment and Energy) will be used to evaluate the potential for adverse effects to benthic life from COPCs in sediment. These values (except for EPA's SQL) are cited for the TCL and TAL compounds to be analyzed during the RI in Tables 2-6 through 208. EPA's SQLs are not included in the tables once received by the m 117 300165 g Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-CO-02 4 Contractor. In the absence of EPA values, values from the published literature will be used I (Smith et al. 1996, OMEE 1993, Jones et al. 1996 NJDEP GSQE 1991). For some contaminants screening values may not be available in the resources listed. If no I screening value is available for a particular COPC from these sources, then a NOAEL will be selected from the scientific literattore. If a NOAEL cannot be found, then a LOAEL from the I literature will be used (with the application of the appropriate uncertainty factor). If necessary, ten-day toxicity tests will be conducted on two invertebrate species, Hyalelle azteca and Chironomous tentans, as part of the ERA. For planning purposes, it is assumed that six tests will be performed in conjunction with ERAs at PSA-specific locations. Data from the toxicity tests will be used to determine biological uptake and the bioavailability of contaminants I in the tested species and other receptor species. I 7.2.2.11 Risk Characterization I In this section of the ERA, potential ecological impacts will be characterized both qualitatively and quantitatively. Information collected during the investigation of site characteristics and habitats will be used to support qualitative evaluations of risk. Quantitative evaluations will be conducted by comparing estimated exposures with appropriate toxicity values. Estimated exposure concentrations for the COPCs will be compared to toxicity reference values (TRVs) by calculating a ratio of the estimated exposure concentration to the TRV, which is termed the environmental effects quotient (EEQ). If the EEQ is less than I.O (indicating the exposure concentration is less than the TRV) then adverse effects are considered unlikely. If the EEQ is equal to or greater than 1.0 (indicating the exposure concentiration is greater than the I TRV), there is a potential for adverse effects to occur. The confidence level of the conclusion increases as the magnitude of the ratio departs from 1.0, For example, there is greater confidence in a risk estimate where the EEQ is 0.1 or 10, than in an EEQ that is closer to 1.0. The potential I magnitude of the toxic effect also increases as the EEQ increases above 1.0. Exposures that exceed a selected toxicity value suggest that adverse effects to ecological resources are possible. I The potential implications of these exceedances will be discussed in detail in the ERA. I 7.2.2.12 Limitations and Uncertainties Uncertainties pertinent to the ERA will be discussed with emphasis on the major sources of I uncertainty affecting the outcome of the ERA. The potential effects of each of these uncertainties I on the risk estimates will be evaluated. 7.2.2.13 Risk Assessment Summary and Conclusions I 118 300166 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-CO-02 P The risks associated with human and ecological exposures to contamination at the PVGCS will be summarized and the conclusions of the ERA will be presented. I 7.2.2.14 Ecological Field Work I In the event that the Phase I screening-level ERA determines that there are potential risks to I aquatic receptors at the PVGCS, ecological field work at the PSA-specific facilities may be required. The ecological field work could include macroinvertebrate and fish bioassessment surveys. The macroinvertebrate community in these streams would be assessed through the use of I the EPA's Rapid Bioassessment Protocol (RBP) Multihabitat Method described in EPA's Revision to Rapid Bioassessment Protocols For Use In Streams And Rivers: Periphyton, Benthic Macroinvertebrates, and Fish (EPA, 1996). The fish community of these streams would be I assessed in a similar manner as the benthic macroinvertebrates. That is, the fish community will be assessed with die RBP for fish as described in EPA (1996). If appropriate, and directed by EPA, the ten-day toxicity tests discussed above will also be conducted. I The field sampling methodologies and protocols for assessing risks to ecological communities I are described in Section 3.5 (Ecological Sampling). TASK 8 TREATABIUTY STUDY/PILOT TESTING 8.1 Disposal of RI/FS Generated Wastes I Waste materials (drill cuttings, PPE, purge water, and decontaminated water) generated I during RI investigations will be containerized separately. In addition. Phase I and Phase U IDW will be sampled, characterized and disposed of separately following the completion of each phase. The Contractor shall assume that all solid wastes generated during the Phase I and Phase n will be I disposed of at a licensed municipal landfill and all liquid wastes will be disposed of at a local POTW. I Approximately 200 drums of soil from drilling activities will be generated during the Phase I and 50 drums of soil will be generated during Phase n. Soil samples will be collected from the I drums suspected of containing highest contaminant concentrations based on earlier sample analyses. Drums containing soil cuttings will be marked with a boring number from which the cutting were generated. Analytical results from soil samples collected from the different soil I borings will be compared. The drums from the five most contaminated boreholes will be sampled. These five samples will be sent to a fixed-basedlaborator y to determine the RCRA I disposal characteristics as required by NJAC 7:26G-6.2 and 40 CFR 261, 119 300167 I ^^s Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0'02 Approximately 70,000 gallons of purge, development, and decontamination water will be generated over the course of the Phase I, and 20,000 gallons of water generated during Phase n. Groundwater samples will be collected and analyzed after each well and temporary well point is developed, purged, or pump tested,iso there will be ample analytical data for all waters containerized in drums and the Baker tank. As a precautionary measure to ensure that the water contained in the drums and/or Baker Tank is appropriate for the recommended disposal option, the Contractor will collect one water sample for every 10,000 gallons of development, purge, decontamination, and other water generated. Therefore, 7 water samples during the Phase I RI and n water samples during the Phase n RI will be analyzed to determine disposal requirements. The water samples will be analyzed for total VOCs, SVOCs, and metals by EPA's CUP and analyzed for the remaining disposal characterization parameters at an independent laboratory. If containerized waters are contaminated to the extent that they cannot be accepted by the POTW for treatment and disposal, then these waters will be set aside for disposal at a RCRA-licensed treatment/disposal facility. The majority of wastewater, however, will be picked up by a 3,000- or 5,000-gallon tanker tiiick and taken to a local POTW for treatment and disposal. Mobile carbon filters (or equivalent treatment method) may be used during aquifer pumping tests to remove contaminants from the water generated. The treated water from the system would be sampled, and if clean, discharged to a surface water body or storm sewer. It is likely that a NJPDES permit would be required by NJDEP before the discharge of treated water would 4 be allowed. PPE, after decontamination, will be treated as debris during Phase I and n, and will be placed in a ten cubic yard dumpster along with other Type 10 and 13 trash. The dumpsters will be emptied every two weeks during the course of the Phase I and n RI, This waste will be disposed of at a non-hazardous facility according to 40 CFR 268.45. TASK 9 REMEDIAL INVESTIGATION REPORT 9.1 Draft Remedial Investigation Report The RI Report will summarize the data collected during die Phase I and II RIs and present the conclusions drawn from all investigated areas. The supporting data and information will be included in its appendices. The results and conclusions of the groundwater modeling described in sub task 6.5 will also be incorporated. The RI report will: describe the results of the field sampling and study area characterization studies conducted during the Phase I and II field investigations; identify the hazards posed to the human health and the environment by the groundwater and soil contamination; and address other RI activities such as data validation and quality assurance. Preparation of the RI report will not delay initiation of the FS unless directed by EPA. 300168 120 Pohatcong Valley Groundwater Contaminatkjn Site May 1999 Statement of Work WAM 037-RI-C0-O2 ^B The RI report will be structured as follows: g o Executive Summary ° Site Background - Site Location 11 - Site IBstory - Site Description Site Demographics o Physical Characteristics - Topography - Geological Characteristics Hydrogeological Characteristics - Surface Water Hydrology B - Ecological Characteristics ° Phase I Field Investigation ^j^ - Potential Source Area Investigation ^^ Soil Gas Investigation El W - Existing Well Sampling ® - Existing Investigations - Shallow Wellpoint Groundwater Sampling - Deep Wellpoint Groundwater Sampling - Surface Soil Sampling - Subsurface Soil Sampling - Summary of Potential Source Area Investigations - Study Area Investigation - Geophysical Investigations - New Monitoring Well Sampling - Existing Well Sampling - Surface Water and Sediment Sampling ° Phase n Field Investigations - Likely Source Area Investigations LS 121 300169 D # Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 - Geophysical Investigation D Soil Gas Investigations - Shallow Wellpoint Groundwater Investigations - Deep Wellpoint Groundwater Investigations Surface Soil Samples - Summary of Likely Source Area Investigation Phase n Study Area Investigation Q Quarterly Sampling Hydraulic Testing D - Dye Tracer Studies ° Environmental Resources Investigations 0 Wetlands Delineations Cultural Resources Investigation Q - Endangered Species Habitat Surveys - Ecological Investigation ° Contaminant Fate and Transport Ground Flow Modeling 0 Contaminant Fate and Transport Modeling ° Baseline Risk Assessment - Human Health Risk Assessment u - Ecological Risk Assessment 0 Summary and Conclusions Q 9.2 Final Remedial Investigation Report n Once comments on the Draft RI are received, the Contractor will prepare a final RI report _J reflecting these comments, consistent with the schedule of activities and deliverables described in Task 1. 9.3 Meetings The Contractor's Project Manager, Site Manager, and one Technical Lead will meet with EPA in New York City for 3/4 of one day to discuss comments on the Draft Remedial D Investigation Report. t 300170 122 Pohatcong Valley Gmundwater Contaminati'on Site May 1999 Statement of Work WAM 037-RI-CO-02 ^^P TASK 10 REMEDIAL ALTERNATIVES SCREENING After assembly, the remedial alternatives will be screened. The objective of this effort is to 0 eliminate from further consideration any alternatives that are undesirable with regard to implementability, effectiveness, and cost. The list of alternatives being considered will be narrowed by eliminating the following types of alternatives: ° Alternatives that are not implementable or technically feasible. 0 ° Alternatives which are significantly more costly than other alternatives but do not provide greater environmental or public health benefits, reliability, or a more permanent solution. Cost will not be used to discriminate between treatment alternatives and non-treatment alternatives. F] ° Alternatives which were unsuccessful at the bench-scale and/or pilot-scale. ° Alternatives which do not appear to be effective based on the results of the Treatability Studies, if applicable. L ° ' Alternatives which do not preserve the range of treatment and containment rn technologies initially developed, where practicable. || Reasons for elimination of any alternative at this stage will be documented in the FS report. T^ For die purposes of estimating for the detailed analysis of alternatives, it is assumed that four remedial alternatives will remain after the screening which will need to be further evaluated for surficial soil contamination, three will remain for subsurface (e.g., potential DNAPL) p^ contamination, and three will remain for the region groundwater contamination. TASK II REMEDIAL ALTERNATIVES EVALUATION 11.1 Remedial Technologies Evaluation ra The universe of remedial technologies and process options which may be effective in the remediation of site contamination will be evaluated and screened in this task. Tables 3-1 and 3-2 list diirty-four proven remedial technologies and process options which may be technically j-, implementable for source area and groundwater contamination identified during the RI. In I addition, as required by the SOW and CERCLA, innovative technologies will also be evaluated as will technologies identified in the Vendor Information System for Innovative Treatment r-j Technologies (VISITT) database, and other references developed for application to Superfund Sites and general engineering standards. Therefore, approximately forty (40) technologies may be screened for remediation of the regional groundwater contamination problem, as well as for f 123 300171 I Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 4 each of the potential source areas identified as contributing to the regional groundwater contamination problem. The overall effectiveness of many technologies, like soil-vapor extraction and treatment or groundwater pumping and treatment, are highly dependent on the contaminant and medium characteristics. Treatability testing may be necessary to obtain operational data to evaluate the technology during the FS. Because the need for, and scope of, treatability studies cannot be determined at this time, such testing will be addressed upon identification of individual source areas as the project proceeds. As required in the Schedule of Activities and Deliverables provided in Attachment 1 of EPA's Amendment to Statement of Work, a summary of evaluation of innovative technologies will be submitted to EPA concurrent with submittal of the Draft RI Report, Remedial alternatives that pass the initial screening process (task 10) and the no-action alternative will be further evaluated in detail and compared to the criteria required in the NCP and in CERCLA, as amended by SARA. As part of this evaluation process, SARA Subsection 121(b)(1) requires that waste, site, and inherent limitations, as well as the ability of each alternative to meet ARARs, be taken into account. For the purposes of estimating for the detailed analysis of alternatives, it is assumed that four remedial alternatives will remain after the P screening which will need to be further evaluated for surficial soil contamination, three will remain for subsurface (e.g., potential DNAPL) contamination, and three will remain for the region groundwater contamination. Criteria for evaluation include; Overall protection of human health and the environment Compliance with ARARs Long-term effectiveness and permanence Reduction of toxicity, mobility, and volume through treatment Short-term effectiveness for reducing toxicity, mobility and volume Implementability Cost State acceptance Community acceptance P To the extent possible, remedial alternatives that involve permanent solutions and alternative I 124 300172 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 flp treatment technologies will be prioritized. The following sections provide a description of each ^^ of the evaluation criteria which will be used in evaluating the selected remedial alternatives r-, identified under Task 10. Overall Protection Of Human Health And The Environment 0 An evaluation will be performed to assess whether each alternative provides adequate protection of human health and the environment. The overall assessment of protection will draw on the assessments conducted under other evaluation criteria described below, especially „ long-term effectiveness and permanence, short-term effectiveness, and compliance with ARARs. This evaluation will focus on whether a specific alternative achieves adequate protection and will describe how risks posed by each exposure pathway are eliminated, reduced or controlled r-i through treatment, engineering, or institutional controls. It will also consider whether an J alternative poses unacceptable short-term or cross-media impacts. Q Compliance With ARARs ARARs must be considered during the detailed evaluation of alternatives. Prior to the ARAR conformance evaluation, chemical-specific, location-specific and action-specific ARARs will jSBlk have been defined. For chemical-specific ARAR evaluation, action levels will be developed to ^Pr provide specific numerical criteria. For location-specific ARARs, floodplains and their impacts on remedial activities will be assumed. During the detailed analysis step, each alternative must p be evaluated to the extent to which it attains ARARs. 1 Long-Term Effectiveness And Permanence I I Altematives will be evaluated in terms of performance which provides significant and permanent reduction in toxicity, mobility, or volume of hazardous waste, and the length of time the level of effectiveness can be maintained. Technologies will be evaluated based on long-term operation and maintenance requirements, including adequacy and reliability of these controls, and demonstrated application at sites with similar contaminants. B The long-term effectiveness and permanence evaluation will focus on the source area 0 problems and the contaminant pathways actually addressed by the altematives. This assessment will also determine to what degree the alternative will protect and improve the environment. Adverse environmental impacts resulting from implementation of the altematives will be described. f 125 300173 D I Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 4 Reduction of Toxicity, Mobility And Volume Through Treatment I Altematives will be assessed for their ability to significantly and permanently reduce the toxicity, mobility or volume of the contaminants. Innovative technologies that provide treatment, resource recovery, or permanent solutions will be given special consideration such that they will not be eliminated simply because they have not been proven. This evaluation will assess whether an alternative will: Satisfy the statutory preference for treatment as a principal element. Irreversibly reduce the principal threats posed by the site. Detoxify/immobilize the target contaminants that pose a risk. Have sufficient capacity to reduce the amount of material remaining in the source area to within acceptable risk as determined in Task 6. Provide high destruction or substrate removal efficiency. Have a positive impact on the site-wide groundwater contamination. Produce a product or residuals that do not pose a threat to human health or the environment or do not require long term management. Short-Term Effectiveness An estimate of the time required to implement the altematives, as well as the time required to achieve beneficial results, will be analyzed. Safety evaluations will include the short-term and long-term (over O&M) affects to nearby communities, environments and workers on-site. If off-site land disposal or containment is considered, the potential threat to human health and the environment from die excavation, transportation, and re-disposal or containment of hazardous waste will be assessed. Implementability Source area- and contaminant- specific characteristics may dictate the technical feasibility of the alternatives. Source area conditions such as the availability of utilities, access road, and weather conditions will favor die implementation of one alternative over another. Many innovative technologies are in the development stage so altematives which use them may not be eliminated because of availability from a sole source or the availability of commercial operations of proven performance. However, should the Contractor determine that poor performance or limited availability of a technology results in the elimination of an alternative, a reasonable P justification will be provided by the Contractor which supports such a decision. Assessment of I 300174 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 operating experience, (i.e., reliability) will most likely be derived from pilot scale tests and/or P from experience of process at similar sites. For off-site treatment altematives, the availability of treatment capacity and proximity to the site will be evaluated. The basic permitting requirements and the projected length of time required to obtain permits will be assessed. Cost Evaluation A detailed cost analysis will be performed for each alternative and will consist of the following steps: • Estimate capital and operation and maintenance costs including long-term maintenance costs; • Calculate annual costs and present worth cost; • Evaluate the sensitivity of cost estimates to changes in key parameters such as discount rates, effective life, variations in quantities or unit cost; and • Assess the potential for future remedial action costs if the remedy fails (replacement costs). For each alternative, the cost will be estimated to an accuracy of -30 percent to +50 percent. The cost analysis will include a separate evaluation of capital and operation and maintenance P costs. Capital costs will consist of short-term installation costs such as engineering/design fees, materials and equipment, constmction, and off-site treatment or disposal. Operation and maintenance costs will consist of long-term costs associated with operating and monitoring the remedial actions. Capital and annual operation and maintenance costs will be based on the anticipated time necessary for the alternative to achieve cleanup criteria. An interest rate of 5 percent will be assumed for all present worth calculations. Cost estimates will be prepared using data from project files, the current EPA Remedial Action Costing Procedures Manual, EPA technical reports, standard references on remedial action costs, and quotations from equipment vendors. Equipment replacement costs will be included when the required performance period exceeds equipment design life. State and Community Acceptance The acceptance of the altematives by the local community and NJDEP will be evaluated, NJDEP acceptance will be assumed for source areas with proposed, in-progress, or implemented remedies conducted under the auspices of state-led regulatory programs. Clearly, a full assessment of community and state attitudes toward the altematives cannot be made until the f 127 300175 I I Pohatcong Valley Gmundwater Contaminati'on Site May 1999 Statement of Work WAM 037-RI-C0-02 4 formal public comment period on the RI/FS report. The evaluation will be limited to the formal comments received during project meetings, previous RI activities, and/or as directed by EPA. 11.2 FS Groundwater Flow and Transport Modeling During the FS, flow and transport models will be used to evaluate remedial altematives. The groundwater flow and transport models developed during the RI will be used for the FS analyses. Modifications to these models (e.g., grid refinement) may be necessary to perform alternative evaluations. The following remedial options may be evaluated: Groundwater recovery wells Groundwater recovery trenches Horizontal wells Injections wells Passive treatment walls Funnel arid gate systems Natural attenuation P Bioremediation Air sparging Peroxide injection Surfactant injection Other alternative/innovative options The computer models will assist in assessing the remedial system feasibility, implementability, approach to management and cost. The models will be used to determine basic system configuration and size. Types of information provided will include number, location and pumping rates of wells, lengths of passive walls and ti:enches,expecte d groundwater influent flow rates and concentration entering the treatment plants and their variability over time. This information is critical for selecting and costing the tireatmentsystems , and ultimately how the system will be managed to optimize cleanup. The FS modeling will also provide estimates of the time required to complete remediation. Analytical solutions will be used to back-calculate die required reductions in source area concentrations, necessary to achieve risk-based concentrations at sensitive receptor locations. The models may also be used to assess the viability of natural attenuation. The numerical flow model (MODFLOW) will be used to design the groundwater recovery systems in order to provide sufficient capture and to estimate recovery flow rates. The flow model will also be used 300176 I 128 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 to determine the dimensions of funnel and gate or passive reactive wall systems, and to evaluate P the expected effect these systems will have on the groundwater flow system. It will also be used to assess groundwater constituent concentrations in time and space. The numerical transport model will provide estimates of tireatmentplan t influent concentration with time and constituent mass removal rates. If fracture flow bedrock cannot- be represented as an equivalent porous medium of the models, then codes such as SWIFT/486 and FRAC3DVS will be considered for use. A meeting with EPA will be held following the screening of the remedial altematives for each source area and for the groundwater plume to obtain concurrence on the list of altematives diat will undergo detailed evaluation. TASK12 FEASIBIUTY STUDY REPORT AND RI/FS REPORT The overall objective of the FS is to make an informed risk management decision regarding which remedial altematives appear to be most appropriate for a given site or area of concem, and will provide protection to human health and the environment. During theFS process. Remedial Action Objectives and Preliminary Remediation Goals will be developed. Remedial technologies will be screened and process options identified and evaluated based on effectiveness, implementability, and relative cost. Selected technologies will be combined into altematives representing a range of treatment and containment options, as appropriate. The remedial alternatives will be screened and the selected altematives evaluated using the nine evaluation P criteria developed to address CERCLA. A comparative analysis will be constructed to evaluate the relative performance of each alternative. The comparative analysis will identify the advantages and disadvantages of each alternative. At the conclusion of the FS process, a FS report describing the aforementioned will be prepared. In scoping the FS, ICF Kaiser assumed that six groundwater contamination source areas will be identified during the RI, containing contaminated soils, sediment, and groundwater. An overall groundwater remedy, separate from the source area remedies, will also be assumed and will be evaluated. For source areas with remedies that have been proposed or implemented under other regulatory programs such as NJDEP's Underground Storage Tank (UST) program. New Jersey's Industrial Site Responsibility Act (ISRA), or RCRA corrective action, the Contractor shall evaluate the effectiveness of the proposed or executed remedy and assess the need for additional measures using the FS criteria. As required in die Schedule of Activities and Deliverables provided in Attachment 1 of EPA's Amendment to Statement of Work, a summary of evaluation of innovative technologies will be submitted to EPA concurrent with submittal of the I>raft RI Report. f 300177 129 I I Pohatcong Valley Groundwater Contaminati'on Site May 1999 Statement of Work WAM 037-RI-CO-02 * 12.1 Development Of Remedial Action Objectives, General Response Actions, and Volumes of Contaminated Media Remedial Action Objectives Based on the data collected in the RI, the remedial action objectives will be developed. Specific action objectives will be developed using a risk-based mediodology to define cleanup levels that will reduce risks to public health and the environment to acceptable levels (this includes ARAR considerations and risk levels as presented in Guidance on Remedial Actions for Contaminated Groundwater at Superfund Sites) [PB89-184-618]. Potential contaminant migration routes and exposure pathways, identified in the Risk Assessment, will be examined further as a basis for estimated acceptable contamination levels. Acceptable exposure levels for potential receptors will be identified and cleanup levels will be estimated by extrapolating from receptor points back to source areas along critical migration routes. Development of response objectives will also include refinement of ARARs specific to source areas, as well as application of ARARs to the Pohatcong Valley site as a whole. General Response Actions General Response Actions will be developed that will satisfy the remedial action objectives. The General Response Actions will be media-specific. As required by SARA and the NCP, die following general response actions will be considered for the remedial action objectives: No Action; Restricted Access/Institutional Controls; Containment; Recovery; Removal; Treatment; or A Combination of These Volumes of Contaminated Media An initial determination will be made of areas or volumes of media to which General p Response Actions will be applied. The determination will be made for each contaminated 300178 I 130 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI'C0-02 medium identified at an estimated six source areas and the overall groundwater contamination p problem. 12.2 Identification Of Applicable Technolo^es And Assembly Of Alternatives - The objective of this task is to develop remedial altematives based on applicable technologies defined in Tasks 10 and 11. The altematives will be developed in accordance with the | requirements of Section 4.2 of the Guidance for Conducting Remedial Investigations and S Feasibility Studies under CERCLA (RI/FS Guidance) EPA/540/G-89/004. The site groundwater conditions appear to result from multiple source areas located across the valley. As such, t remedial altematives will be developed each individual source area identified, as well as for the 5 regional groundwater contamination. For the purposes of estimating, it is assumed that six soil and four groundwater remedial altematives will need to be developed and screened for each of the M six estimated PSAs. Additionally, it is estimated that four remedial altematives will need to be ® developed and screened for the regional groundwater contamination. This will require for each PSA and the regional groundwater contamination: the evaluation of remaining remedial B technologies and process options from the screening evaluation; the assembly of the remaining technologies and process options into remedial altematives; and die screening of the altematives ^ as described below. ' B These altematives will be screened as described in Section 4.2 of the R^FS Guidance and using the defined set of criteria contained in the National Contingency Plan, 40 CFR 300. Only those altematives which are acceptable based on the initial screening process will undergo full evaluation. CERCLA, as amended by SARA, states that to the maximum extent practicable, remedial actions that utilize permanent solutions and alternative ti:eatment technologies or resource recovery technologies should be utilized to the fullest practical extent. Therefore, remedial altematives that use these technologies will be prioritized when compared with remedial altematives which utilize institutional controls or containment to achieve remedial action objectives. To the extent possible, treatment options will range from altematives that eliminate the need for long-term management at the site to altematives involving treatment that would reduce toxicity, mobility, or volume as a principal goal, and will include innovative technologies to the extent possible. The Conti-actor's Project Manager, Site Manager, and one Technical Lead will meet with EPA in New York City for 3/4 of one day to discuss the list of altematives. 12.3 Draft Feasibility Study Report The Draft FS report will summarize the findings of sub tasks 12.1 through 12.4, compare the « 131 300179 Pohatcong Valley Groundwater Contaminati'on Site May 1999 Statement of Work WAM 037-RI-CO-02 4 remedial altematives, and provide a basis for which EPA can select the most appropriate altemative for each source area and the site groundwater. The Draft FS Report will also include a discussion of the HHRH and ERA, The Remedial Action Objectives, and the ARARs which will influence the performance of the remedial action. The Contractor will proceed with this task only after consultation with EPA regarding the scope of die report for each source area and site groundwater. The Draft FS report will include the following sections: Executive Summary — A brief summary of the entire Draft FS report. 1.0 Introduction — presentation of the purpose of the FS, background information as summarized in the RI report, a discussion of contaminant fate and transport, and discussion of the human and ecological risk assessments. Other discussions to be incorporated include the remedial action objectives and the ARARs which will influence the performance of the remedial action. The source areas will also be described in this section, including land use considerations. 2.0 Feasibility Study for Source Area 1 ^a 2,1 Identification and Screening of Technologies - A discussion of the process and results of Tasks 10 and 11 for Source Area 1. 2.2 Development and Screening of Altematives - A discussion of the process and results of %-, Tasks 10 and 11 for Source Area 1. 2.3 Detailed Analysis of Altematives - A discussion of the process and results of Task 11 for Source Area, including comparative analysis of altematives. 3.0 Feasibility Study for Source Area 2 1 '.< '., 4.0 Feasibility Study for Source Area 3 m 1 5.0 Feasibility Study for Source Area 4 6.0 Feasibility Study for Source Area 5 J32 300180 Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-O2 7,0 Feasibility Smdy for Source Area 6 f" 8.0 Feasibility Study for Overall Groundwater Plume T 9.0 Summary and Conclusions - The Draft FS report will be summarized and the conclusions r for each source area and the overall groundwater plume will be presented. L Bibliography L Appendices ' (_ The Draft FS report will be prepared in accordance with the Guidance for Conducting (__ Remedial Investigations and Feasibility Studies Under CERCLA and submitted to EPA for review. i pi 12.4 Final Feasibility Study Report ^jjjk I Comments received from EPAiwill be incorporated into the Final FS report. 0 12.4.1 Meetings The Contractor's Project Manager, Site Manager, and one Technical Lead will meet with EPA in New York City for 3/4 of one day to discuss comments on the Draft Feasibility Study Report. TASK 13 POST RI/FS SUPPORT The Contractor will be required to provide both community relations and technical support during the Post-RI/FS phase. The Contractor shall assume that EPA will hold a public meeting to discuss its Proposed Plan with die public. This meeting (herein referred to as the "Proposed Plan Public Meeting") will be held in addition to the public meetings planned in Task 2. This task consists of the following SubTasks: 13.1 Public Notices The Contractor shall prepare two draft and final public notices and place them in the most 0 widely read local newspapers. The first public notice will announce the public comment period. f 133 300181 0 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 the Proposed Plan Public Meeting, and availability of the Proposed plan for review at the information repositories. The second public notice will announce an extension of the public comment period, (Note: this notice will be needed only if EPA receives a request from die community to extend the public comment period, and in turn, directs the Contractor to prepare the notice.) 13.2 Proposed Plan The Contractor shall prepare a draft and final Proposed Plan. The Contractor shall also edit, lay out, reproduce, and mail copies of the Proposed Plan to people on the site mailing list and to the information repositories. Extra copies will be made for the public meeting. Existing site maps and graphics from previous fact sheets will be used (see SubTask 102.03). EPA experience has shown that oftentimes, scheduling does not allow time for reproduction of the Proposed Plan in booklet format. Based on diis, it should be assumed that the Proposed Plan will be 16, double-sided pages, and stapled in the top left comer. 13~3 Proposed Plan Public Meeting The Contractor shall provide both community relations and technical support for this SubTask, The following activities will be conducted under this SubTask; Identify, recommend, and reserve a meeting site; Provide logistical support (e,g,, audio-visual equipment rental and delivery, room fees); Prepare an agenda, sign-in sheets, tent cards, approximately 20 overhead transparencies, and a computer-generated presentation; Assist widi a dry-mn; Reproduce and distribute handouts; Attend the public meeting; and Coordinate for a court reporter to record the meeting and provide a transcript. The Contractor's Site Manager, technical expert, and community relations specialist will attend and assist EPA during the public meeting. Costs for die site Manager or technical expert to prepare and give a presentation at the public meeting may be required in the future on an as needed basis. The Contractor shall review the transcript for grammatical or spelling errors. If any are found, the contractor will have the court reporter revise the transcript, one original and p two copies of the corrected transcript will be fumished to EPA and one copy of the transcript will I 134 300182 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037'RI-C0-02 be sent to the information repositories, 13.4 Responsiveness Sununary I^ Following the Proposed Plan Public Meeting, die Contractor will prepare a draft and final I» Responsiveness Summary, Also, the Contractor will compile all oral and written comments received during the public comment period and, will further provide technical expertise in I responding to comments on the Remedial Investigation/Feasibility Study and Proposed Plan. The ™ Contractor will provide EPA with both a hard copy and disk version of the draft and final Responsiveness Summary. S TASK 14 NEGOTIATION SUPPORT (not used at this time) i TASK 15 ADMINISTRATIVE RECORD (not used at this time) • TASK 16 WORK ASSIGNMENT CLOSEOUT ,. 1 16.1 Technical File Closeout This task includes the closeout of the Work Assignment Technical Files and the preparation of the Work Assignment Completion Report (WACR). Initiation of this task will not proceed until I the Contractor receives written confirmation from the WAM tiiat technical work has been completed on this WA. I IP 16.2 Accounting File Closeout M Prior to initiating the closeout, the Contractor and EPA WAM and Project Officer will meet to decide upon the exact scope of the closeout task. The typical SubTasks associated with closeout I include: collecting files (e.g., EPA deliverables and EPA correspondence); organizing files; inspecting files; duplicating files; and forwarding original files and microfiche, if requested, to the WAM. I I 16.3 WACR Preparation 8 The Contractor shall initiate work assignment closing upon notification via the work assignment form from the Contracting Officer. I m 135 300183 • I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 I REFERENCES Boss International and Brigham Young University, 1996. Groundwater Modeling System (GMS), User's Manual, Version 2.1. Madison, Wisconsin. Cohen, R.M., and Mercer, J.W. DNAPL Site Evaluation. U.S. Robert S. Kerr Environmental Research Laboratory, Ada, OK. U.S. Environmental Protection Agency Report No. EPA/600/R-93/022. February 1993. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. U.S. Department of Interior, Fish and Wildlife Service, Office of Biological Services, Washington, DC.. FWS OBS-79/31 Fetter, C.W. 1992. Contaminant Hydrology. Macmillan Publishing Company. Fischer, H. B., E, J, List, R. C. Y. Koh, J. Imberger and N. H. Brooks, 1979. Mixing in Inland and Coastal Waters. Academic Press, Foster, S. and Chrostowski, P. 1987. Inhalation Exposures to Volatile Organic Contaminants in the Shower. Presented at the 80th Annual Meeting of APCA, New York, NY. Gilbert, R.O. 1987. Statistical methods for environmental pollution monitoring. VanNostrand Reinhold, New York, NY. ICF Technology, Incorporated. 1989. Draft phase I work plan, Pohatcong Valley Groundwater p Contamination Site, Warren County, New Jersey. ICF Technology, Inc., Edison, NJ. Javandel, I., C. Doughty, and C. Tsang, 1984, Groundwater Transport: Handbook of Mathematical Models. Water Resources Monograph Series 10, American Geophysical Union, Washington, DC. Jones, D.S., R.N. Hull, and Suter, G.W. 1996. Toxicological Benchmarks for Screening Contaminants of Potential Concem for Effects on Sediment-Associated Biota: 1996 Revision. Risk Assessment Program, Health Sciences Research Division, Oak Ridge National Laboratory. ES/ERyTM-95/R2. McDonald, M, G. and A. W. Harbaugh. 1984, A Modular Three-Dimensional Finite Difference Ground-Water Flow Model, U.S, Geological Survey. Mercer, J.M., and Cohen, R.M. A review of immiscible fluids in the subsurface: Properties, models, characterization and remediation. J, Con tarn. Hydrol. 6:107-163. 1990. Department of Environmental Protection (NJDEP) 1991. Draft Guidance for Sediment Quality Evaluations. Division ofPublicly Funded Site Remediation. Ontario Ministry of the Environment and Energy (OMEE), 1993. Guidelines for the Protection and Management of Aquatic Sediment Quality in Ontario. Water Resources Branch, Ontario Ministry of the Environment and Energy. Opresko, D.M., B.E. Sample, and G.W. Suter. 1994. Toxicological benchmarks for wildlife: 1994 Revision. U.S. Department of Energy, Oak Ridge National Laboratory, Oak Ridge, I 136 300184 Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037'RI-C0-02 TN. ES/ER/TM-86/R1. Papadopulos & Associates, Inc. and MathSoft, Inc. 1994. Aquifer Data Evaluation for Pumping Tests (ADEPT). ^S Pollock, D. W. 1989. Documentation of Computer Programs to Compute and Display Pathlines Using Results from the U.S. Geological Survey Modular Three-Dimensional Finite- H Difference Ground-Water Flow Model, U. S, Geolo^cal Survey. Open File Report 89- 381. ^ Smith, S.L., MacDonald, D.D., Keenleyside, K.A., Ingersoll, C,G„ and Field, L.J, 1996, A IR preliminary evaluation of sediment quality assessment values for freshwater ecosystems, Joumal of Great Lakes Research 22:624-638, ffi Suter, G.W. 1993. Ecological Risk Assessment. Lewis Publishers, Chelsea, MI. Suter, G.W., n, and Tsao, C.L. 1996. Toxicological Benchmarks for screening potential H contaminants of concem for effects on aquatic biota: 1996 revision. Risk Assessment • Program, Health Sciences Research Division, Oak Ridge National Laboratory, Oak Ridge, TN. ES/ERyTM-96/R2. I Thomthwaite, C.W. and J.R. Mather, 1955. The water balance, Drexel Institute of Technology, Publ. in Climatology, 8(1), 104 pp. U.S. Army Corps of Engineers (USACE). 1987. Corps of Engineers Wetlands delineation manual. U.S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, MS. ES/ERyTM-96/R2. t U.S. Environmental Protection Agency (USEPA). 1997a. Risk-Based Concentration Table, USEPA Region ni. U.S. Environmental Protection Agency (USEPA). 1997b, Ecological risk assessment guidance for Superfund: Process for designing and conducting ecological risk assessments. Interim final. U.S, Environmental Protection Agency, Environmental Response Team, Edison, NJ. U.S. Environmental Protection Agency (EPA). 1996. Revision to Rapid Bioassessment Protocols For Use In Streams And Rivers: Periphyton, Benthic Macroinvertebrates, and Fish, U.S. Environmental Protection Agency (USEPA). 1996a. Proposed guidelines for ecological risk assessment. EPA/630/R-95/002B. Risk Assessment Fomm, U.S. Environmental Protection Agency, Washington, DC. I U.S. Environmental Protection Agency (USEPA). 1996b- Drinking Water Regulations and Health Advisories. Office of Water, Washington, D.C. EPA 822-B-96-002 U.S. Environmental Protection Agency (USEPA), 1996c, Ecotox Thresholds. ECO Update 3(2): 1-12. U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, Washington, DC. EPA 540/F/95/038. U.S. Environmental Protection Agency (USEPA). 1996d. Revision to Rapid Bioassessment Protocols For Use In Streams And Rivers: Periphyton, Benthic Macroinvertebrates, and I Fish. Revision date: October 31,1996. m 137 300185 I I Pohatcong Valley Gmundwater Contamination Site May 1999 Statement of Work WAM 037-RI-C0-02 p U.S. Environmental Protection Agency (USEPA). 1995a. Quality Criteria for Water 1995. Draft. U.S. Environmental Protection Agency, Health and Ecological Criteria Division, Office of Water, Washington, D.C. U.S. Environmental Protection Agency (USEPA). 1995b. Region IH BTAG Screening Levels. Draft. US Environmental Protection Agency, 1994. Ground-Water Modeling Compendium. Second Edition. Model Fact Sheets, Descriptions, Applications and Cost Guidelines. EPA/500/B- 94/004. U.S. Environmental Protection Agency (USEPA), 1994. Revised Interim Soil Lead Guidance for CERCLA Sites and RCRA Corrective Action Facilities. OSWER Directive 9355.4-12. U.S. Environmental Protection Agency (USEPA). 1993. Technical Basis for Deriving Sediment Quality Criteria for Nonionic Organic Contaminants for the Protection of Benthic Organisms by Using Equilibrium Partitioning. U.S. Environmental Protection Agency, Office of Water, Washington, D.C. EPA-822-R-93-011. U.S. Environmental Protection Agency (USEPA). 1992a. Framework for ecological risk assessment. Risk Assessment Forum, U.S. Environmental Protection Agency, Washington. DC. EPA/630/R-92/001. U.S. Environmental Protection Agency (USEPA). 1992b. Supplemental Guidance to RAGS: Calculating the Concentration Term. Office of Solid Waste and Emergency Response. U.S. Environmental Protection Agency (USEPA). 1992c. Guidelines for Exposure Assessment. p Federal Register 57:22888-22938. U.S. Environmental Protection Agency (USEPA). 1992d. Dermal Exposure Assessment: Principles and Applications. Interim Report. Office of Research and Development, Washington, D.C. EPA/600/8-91/OOIB. U.S. Environmental Protection Agency (USEPA). 1991a. Risk Assessment Guidance for Superfund. Volume I: Human Health Evaluation Manual Supplemental Guidance. Standard Default Exposure Factors. Interim Final. Washington, D.C. OSWER Directive 9285.6-03. U.S. Environmental Protection Agency (USEPA). 1991b. Role of Baseline Risk Assessment in Superfund Remedy Selection Decisions. Office of Solid Waste and Emergency Response. OSWER Directive 9355.0-30. U.S. Environmental Protection Agency (USEPA). 1989. Risk Assessment Guidance for Superfund. Volume I: Human Health Evaluation Manual. Interim Final, OSWER Directive 9285.7-0 la. U.S. Environmental Protection Agency (USEPA). 1986. Quality Criteria for Water, 1986. U.S. Environmental Protection Agency, Office of Water, Washington, D.C. EPA/440/5- 86/001. Will, M.E. and G.W. Suter. 1994a. Toxicological benchmarks for screening potential p contaminants of concem for effects on soil and litter invertebrates and heterotrophic 300186 138 I Pohatcong Valley Groundwater Contamination Site May 1999 Statement of Work WAM 037-RI'C0-O2 ^tP process. U.S. Department of Energy, Oak Ridge National Laboratory, Oak Ridge, TN. ^mr ES/ERyTM-126. Will, M.E. and G.W. Suter. 1994b, Toxicological benchmarks for screening potential contaminants of concem for effects on terrestiial plants, U.S. Department of Energy, Oak Ridge National Laboratory, Oak Ridge, TN, ES/ER/rM-85/Rl. Zar, J.H. 1984. Biostatistical Analysis. Second Edition. Prentice-Hall, Inc., Englewood Cliffs, NJ, • 300187 139 I