FIFTH FIVE-YEAR REVIEW REPORT FOR LAUREL PARK LANDFILL SUPERFUND SITE BOROUGH OF NAUGATUCK NEW HAVEN COUNTY, CONNECTICUT
Prepared by
U.S. Environmental Protection Agency Region 1 Boston, Massachusetts
Bryan Olso , D · tor Date Office of Site Remedia tion and Restoration Table of Contents LIST OF COMMON ABBREV IATIONS & ACRONYMS ...... 3 I. INTRODUCTION ...... 4 FIVE-YEAR REVIEW SUMMARY FORM ...... 5 11. RESPONSE ACTION SUMMARY ...... 5 Basis for Taking Action ...... 5 Response Actions ...... 6 Status of ln1plementation ...... 8 IC Sun1n1ary Tables ...... 9 Operation & Maintenance and Long-term Monitoring ...... I I III. PROGRESS SINCE Tl-I E LAST REVIEW ...... 11 IV. FIVE-YEAR REV IEW PROCESS ...... 12 Community Notification, Involvement & Site Interviews ...... 12 Data Review ...... 14 Site Inspection ...... 19 V. TECJ-INlCAL ASSESSMENT ...... 20 QUESTION A: ls the remedy functioning as intended by the decision documents? ...... 20 QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels, and remedial action objectives (RA Os) used at the time of the remedy selection still valid? ...... 22 QUESTION C: I-las any other info m1ation come to light that could call into question the protectiveness of the rernedy? ...... 27 YI. ISSUES/RECOMMENDATIONS ...... 27 OTI-IER FIN DINGS ...... 28 VI I. PROTECTIVENESS STATEMENT ...... 28 VIII . NEX'r REVIEW ...... 29 APPEN DIX A - REFERENCE LIST ...... 30 APPEN DIX B - ADDITIONAL DA TA TABLES AN D FIGURES
2 LIST OF COMMON ABBREVIATIONS & ACRONYMS
ARAR Applicable or Relevant and Appropriate Requirement CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CFR Code of Federal Regulations coc Contaminant of Concern CT DEEP Connecticut Department of Energy and Environmental Protection CTDPH Connecticut Department of Public Health EPA United States Environmental Protection Agency FYR Five-Year Review GES Groundwater Extraction System GWPC Groundwater Protection Criteria GWPS Groundwater Protection Standards gpm gallons per minute ICs Institutional Controls LC/GES Leachate Collection/Groundwater Extraction System LPC Laurel Park Coalition LTMP Long-Term Monitoring Plan MCL Maximum Contaminant Level mg/Kg milligrams per kilogram mg/L milligrams per liter NPL National Priorities List NWPCF Naugatuck Water Pollution Control Facility OSWER Office of Solid Waste and Emergency Response OU Operable Unit O&M Operation and Maintenance PFAS Per- and Polyfluoroalkyl Substances POTW Publicly-Owned Treatment Works POC Point of Compliance RAO Remedial Action Objective RCRA Resource Conservation and Recovery Act RI/FS Remedial Investigation/Feasibility Study ROD Record of Decision RSR Remediation Standard Regulation SWPC Surface Water Protection Criteria TPY tons per year µg/L micrograms per liter voe Volatile Organic Compound
3 I. INTRODUCTION
The purpose of a Five-Year Review (FYR) is to evaluate the implementation and performance of a remedy in order to determine if the remedy is and will continue to be protective of human health and the environment. The methods, findings, and conclusions of reviews are documented in reports such as this one. In addition, FYR reports identify issues found during the review, if any, and document recommendations to address them.
The U.S. Environmental Protection Agency (EPA) is preparing this five-year review pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Section 121 , consistent with the National Contingency Plan (NCP)(40 CFR Section 300.430(f)(4)(ii)), and considering EPA policy.
This is the fifth FYR for the Laurel Park, Inc. Superfund Site (the "Site"), more commonly referred to as the Laurel Park Landfill Superfund Site. The triggering action for this statutory review is the completion date of the last FYR in September 2013. The FYR has been prepared due to the fact that hazardous substances, pollutants, or contaminants remain at the site above levels that allow for unlimited use and unrestricted exposure (UU/UE).
The Site consists of one Operable Unit (OU) that will be addressed in this FYR.
The Laurel Park Landfill Superfund Site FYR was led by Karen Lumino, Remedial Project Manager for EPA Region 1. Other participants from EPA Region 1 include Joy Sun (Senior Enforcement Counsel); Courtney Carroll (Human-Health Risk Assessor); Bart Hoskins (Ecological Risk Assessor); and ZaNetta Purnell (Community Involvement Coordinator). Sheila Gleason (Environmental Analyst) with the Connecticut-Department of Energy and Environmental Protection (CT DEEP) also participated in this review. The Settling Defendants were notified of the initiation of the five-year review which began on November 20, 2017.
Site Background
The Laurel Park Landfill Superfund Site is located in the Borough of Naugatuck, Connecticut, approximately 1 mile west of the Naugatuck River and Connecticut Route 8, and encompasses 35 acres on Huntington Hill (a.k.a. Hunter's Mountain) (Figure 1). The capped landfill occupies 19 acres, and sits in glacial till on the eastern slope and on weathered bedrock on the western flank. A chain-link fence extends around the perimeter of the Site. Beyond the fenceline, most of the area is forested. Adjacent land use is dominated by residential development. Surface water from the landfill flows into Spruce Brook and Long Meadow Pond Brook which are tributaries to the Naugatuck River, located 1 mile west of the Site. Long Meadow Pond Brook is fed by an unnamed stream that begins at the base of the landfill. Groundwater in the vicinity of the Site flows predominately within the shallow bedrock in a north-northwesterly direction. In the shallow and deep overburden, the flow has a more northerly component.
4 Both sanitary and industrial waste were accepted at the landfill from the late 1930s until it closed in 1987. Operational problems at the landfill were first reported in the early 1960s. Complaints included chemical spills on roads leading up to the landfill, large quantities of black acrid smoke, unpleasant odors and blowing litter. Leachate from the landfill was found to be running into surface water. The Site was listed on the National Priorities List (NPL) in 1983. Also in 1983, as a condition of their operating permit, the State of Connecticut ordered Laurel Park, Inc., to provide residents with bottled water, until construction of a public water line was completed.
FIVE-YEAR REVIEW SUMMARY FORM
SITE IDENTIFICATION
Site Name: Laurel Park, Inc. Superfund Site EPA ID: CTD98052 I I 65 City/County: Borough ofNaugatuck/New Haven
NPL Status: Final Multiple OUs? Has the site achieved construction completion? No Yes
REVIEW STA TUS
Lead agency: EPA Author name: Karen Lumino, Remedial Project Manager Author affiliation: MENT/CT Superfund Section, OSRR, EPA Region I Review period: 11/20/2017 - 9/4/2018 Date of site inspection: 4/12/2018 Type of review: Statutory Review number: 5 Triggering action date: 9/25/2013 Due date (five years after triggering action date): 9/25/2018
II. RESPONSE ACTION SUMMARY
Basis for Taking Action
The Remedial Investigation/Feasibility Study (RVFS) was conducted from 1985 to 1987. The RVFS concluded that the existing leachate collection system was only partially effective in capturing leachate. Leachate continued to contaminate soil, surface water, and groundwater in the vicinity of the Site.
5 The RI included an Endangerment Assessment that was completed in 1987. EPA determined that the consumption of groundwater from residential wells in the vicinity of the Site represented the most significant risk to human health. Volatile organic compounds (VOCs), other organic compounds, and metals were detected in groundwater at concentrations well above levels considered to be protective. Moreover, because the landfill did not have a barrier to prevent precipitation from coming into contact with the landfill wastes, the generation of leachate would continue and the potential existed for further degradation of groundwater quality to levels that would endanger public health, if consumed. Potential exposure to contaminated landfill soil, surface water, and sediment was considered to pose relatively low risk when compared with the potable use of groundwater.
Response Actions
On April 16, 1987, Laurel Park, Inc. informed the Connecticut Department of Environmental Protection (now known as the Department of Energy and Environmental Protection, hereinafter "CT DEEP") that they had ceased accepting wastes. Prior to this, the Connecticut Superior Court in Hartford issued a judgment on February 1, 1983, ordering Laurel Park, Inc. to take the following steps as conditions for allowing it to continue accepting solid waste:
Immediately prepare a proposal for groundwater monitoring and implement the proposal upon approval by CT DEEP.
• Install and maintain a leachate collection and treatment system, upon approval of plans by CT DEEP, by October 31, 1983.
• Submit a performance bond to CT DEEP covering the cost of installing and maintaining the leachate system for five years.
Supply potable water (i.e., bottled water) to certain specifically identified neighboring residents.
• Provide a municipal water system to those residents if Laurel Park, Inc. applies for and receives permission for horizontal expansion of the landfill.
As a result of the judgment, Laurel Park, Inc. completed construction of a leachate collection and treatment system in 1984 and provided bottled water to area residents whose private water supply was affected by the Site. In May 1987, EPA entered into an Administrative Order on Consent (AOC) with the State of Connecticut, the Borough of Naugatuck and the Uniroyal Chemical Company (the largest generator of waste at the Site) to design and install the waterline referenced in the 1983 judgment described above.
6 The Remedial Action Objectives (RAOs) specified in the 1988 Record of Decision (ROD) included measures to mitigate existing and future threats to public health and the environment.
Source Control
1. Prevent or minimize the further release of contaminants in groundwater, surface water, sediments, soil and air.
2. Eliminate the threats posed to human health and the environment from the source area itself.
Management of Migration
1. Prevent or minimize further migration of contaminants in groundwater, surface water, sediments, soil, and air.
2. Eliminate or minimize the threats posed to human health and the environment from the current extent of contamination.
The remedy selected for the Site in the 1988 ROD includes the following components:
• Grading and placement of a multi-layer cap consistent with Resource Conservation and Recovery Act (RCRA) Subtitle C over the entire landfill;
• Construction of a leachate collection system and a groundwater extraction system;
• Treatment of the captured leachate and the contaminated groundwater at the Naugatuck Water Pollution Control Facility (NWPCF);
• Long-term monitoring of groundwater, surface water, and landfill gas; and
• Institutional controls.
The 1988 ROD established the following performance standards for the cap and leachate collection/groundwater extraction system based on the State of Connecticut's GB/GA classification of groundwater at the Site (i.e., known to be degraded, with a groundwater quality goal of being potable without the need for pretreatment):
1. Maintain the cap to minimize infiltration and ensure the dewatering of the landfill.
7 2. Meet the RCRA Groundwater Protection Standard1 at each of the Point of Compliance2 bedrock groundwater monitoring wells.
3. A concentration standard that is satisfied when the concentration of contaminants in the groundwater has stabilized due to the reduced generation of leachate.
4. A hydraulic standard that is satisfied when the water table has been lowered below the waste and the generation of leachate has ceased or been reduced to a minimum due to dewatering of the landfill.
Status of Implementation
With the exception of institutional controls (ICs) , all components of the source control and management of migration response actions have been implemented. The water line was completed in the spring of 1989 and residents with private water supplies within a 1,000-foot radius of the site and at risk from contamination were connected. Three residences originally declined the offer to connect to the water line. The Laurel Park Coalition (LPC) (i.e., the Settling Defendants of the 1992 Consent Decree) who are performing the remediation, has confirmed that two of the three have subsequently connected to public water. In March 2015, the LPC sent a certified letter to the owner of the third property, located on Hunters Mountain Road, requesting permission to collect a sample from the private water supply well. The owner returned the permission form indicating that she did not want the well tested and further requested that the LPC stop sending letters requesting to sample her well. On July 6,2018, Karen Lumino spoke with Amanda Deming of Connecticut Water, the regional water authority, and confirmed that they do not provide that residential property with public water. However, this property is not likely to be impacted by Site contaminants of concern (COCs) as it is both up- and cross-gradient from the regional northwesterly flow of groudwater. Construction of the cap, and, leachate collection and groundwater extraction system (LC/GES) was completed in 1998.
Institutional controls are needed to restrict certain activities on the Site and adjacent to the Site. The LPC prepared and submitted an IC Plan in September 201 1, which was approved by EPA in January 2012. On February 25, 201 5, deed restrictions were recorded on the two parcels owned by the LPC, Tax Lots 6W-9.5B and 6W-49.5. Efforts to record !Cs on the remaining parcels are underway. The ICs are summarized below, and the impacted parcels are depicted in the map included as Figure 3.
1 Defined in the Statement of Work for Remedial Design and Remedial Action (Appendix II to Consent Decree 3-9 l-CY- 249, effective August 1992) as: i) the background levels of the hazardous constituents; ii) the Maximum Contaminant Levels (MCLs) for those constituents for which MCLs have been established; or iii) alternate limits established by EPA under 40 C.F.R § 264.94(b) known as "Alternate Concentration Limits".
2 Point of Compliance is defined in the RCRA regulations as the hydraulically downgradient limit of the waste management area that extends down into the uppennost aquifer underlying the unit. 8 IC Summary Tables
T a ble 1 S ummary o flmp ementedlC s ,. -· Media, engineered [Cs ICs'Called ilm'pacted rrc Title ofIC Instrument controls, and areas Needed for in the Parcel(s) Ii Objective Implemented and that do not support Decision .•i Date UU/UE based on Documents I current conditions Land Use Yes Yes H/6W9.5B Parcel shall not be Declaration of I/6W49.5 used for any Environmental Land residential activity. Use Restriction and Grant of Easement Construction of February 2015 buildings shall not be permiteed except for certain purposes, including for O&M activities. Engineered Control Yes Yes H/6W9.5B To protect Declaration of I/6W49.5 components of the Environmental Land remedial action Use Restriction and located within the Grant of Easement parcel ( cap, leachate February 2015 collection system, groundwater extraction system, etc.) Uncapped Soil Yes Yes H/6W9.5B Soil greater than four Declaration of 1/6W49.5 feet below grade shall Environmental Land not be exposed Use Restriction and except for certain Grant of Easement purposes, including February 20 l 5 for O&M activities. Groundwater Yes Yes H/6W9.5B Groundwater shall Declaration of l/6W49.5 not be used for any Environmental Land purpose other than Use Restriction and hydraulic Grant of Easement containment, February 2015 treatment and/or monitoring of groundwater in accordance with the remedial action. Surface Water Yes Yes H/6W9.5B Surface water shall Declaration of l/6W49.5 not be used for any Environmental Land purpose, including Use Restriction and but not limited to Grant of Easement drinking, swimming February 2015 or wading.
9 Ta bl e 2 S ummaryo f Pl annedI C s Media, engineered ICs ICs Called Impacted lC Title oflC Instrument controls, and areas Needed for in the Parcel(s) Objective Planned that do not support Decisio)l I ,-, UU/UE based on Documents I current conditions Land Use Yes Yes H/6W13 (I & 2) Parcel shall not be Declaration of H/6W14 used for any Environmental Land H/6W3 1 residential activity. Use Restriction and H/6W34 ( I & 2) Grant of Easement H/6W35 I/6W37 H/6W40 I/6W54 I/6WSS I/6WS9 Land Use Yes Yes H/6Wl3 (I & 2) Construction of Declaration of H/6Wl4 buildings shall not be Environmental Land H/6W34 ( I & 2) permitted except for Use Restriction and l/6W37 certain purposes Grant of Easement H/6W40 including for O&M I/6WS4 activities. I/6W59 Engineered Control Yes Yes H/6Wl3 (I & 2) To protect Declaration of H/6W14 components of the Environmental Land H/6W3 I Remedial Action Use Restriction and H/6W34 ( I & 2) located within the Grant of Easeme nt H/6W35 parcel ( cap, leachate I/6W37 collection system, H/6W40 groundwater l/6W54 extraction system, I/6W59 etc.) Uncapped Soil Yes Yes H/6W13 (I & 2) Soil greater than four Declaration of H/6W14 feet below grade shall Environmental Land H/6W34 ( I & 2) not be exposed Use Restriction and I/6W37 except for certain Grant of Easement H/6W40 purposes, including I/6W54 for O&M activities. I/6WS9 Groundwater Yes Yes H/6Wl3 (1 & 2) Groundwater shall Declaration of H/ 6W1 4 not be used for any Environmental Land H/ 6W3 1 purpose other than Use Restriction and H/6W34 (I & 2) hydraulic Grant of Easement H/6W35 containment, J/6W37 treatment and/or H/6W40 monitoring of I/6W54 groundwater in l/6W55 accordance with the I/6W59 remedial action. Surface Water Yes Yes H/6Wl3 ( I & 2) Surface water shall Declaration of H/6Wl4 not be used for any Environmental Land H/6W31 purpose, including Use Restriction and H/6W34 ( I & 2) but not limited to Grant of Easement IO Media, engineered ICs I Operation & Maintenance (O&M) and Long-Term Monitoring (LTM) The LPC conducts routine operation and maintenance activities of the physical components of the remedy (cap and LC/GES) in accordance with the O&M Plan that was approved by EPA in December 1998. The primary activities associated with O&M include: • Monthly inspections of the landfill cap, and, as necessary, mowing, fertilizing and seeding, bench repair, and clearing brush from the fence line and stormwater chutes. • Monthly inspections of the 21 GES wells. Fifteen of the GES wells have pneumatic pumps that are cleaned and/or repaired annually. • Annual inspection and periodic cleaning of the leachate transfer line. Monthly inspection of the flume and flow meter at the leachate station. The L TMP has been modified several times since EPA approved it in 1998, as the data collection strategy has transitioned from characterization and remedy implementation to long-term remedy effectiveness. In March 2015, the LPC requested four modifications to the sampling and analysis plan, which was last updated in October 2009. EPA approved two of the modifications, with conditions: • Analysis for mercury, silver, and beryllium would not be required for groundwater sample collection in 2015 and 2016 only. The decision to eliminate these three analytes from future sampling events will be re-evaluated after review of the 2017 dataset, as part of this FYR. • A reduction in groundwater sampling from three times a year to twice a year to coincide with typical high and low groundwater periods. EPA also approved a reduction in the required number of progress reports from three a year (two semi-annual progress reports and an annual report) to two, on the condition that the second semi-annual report include the year-end evaluation of trends previously included in the annual report. III. PROGRESS SINCE THE LAST REVIEW This section includes the protectiveness determinations and statements from the last five-year review as well as the recommendations from the last five-year review and the current status of those recommendations. 11 Table 3: Protectiveness Determinations/Statements from the 2013 FYR Protectiveness OU# Protectiveness Statement Determination Sitewide Short-term Protective The remedy is currently protective of human health and the environment in the short-term because: (I) the cap is preventing direct contact exposures to landfill contaminants and minimizes contaminant migration; (2) the leachate collection and groundwater extraction system is containing the majority of groundwater contaminants on-Site; and (3) the waterline installed along Hunters Mountain Road helps to ensure that adjacent residents are not exposed to potential Site groundwater contamination. To make a long-term protectiveness determination Institutional Controls must be finalized and further sampling, analvsis and evaluation of 1.4-dioxane must be oerformed. Table 4: Status of Recommendations from the 2013 FYR Current Current Implementation Completion Issue Recommendations Status Status Description Date (if applicable) rn stitutional Implement all O ngoing ICs were recorded on the two NIA Controls have not necessary parcels owned by the Laurel Park been fu lly institutional Coalition on February 25,2015. implemented. controls. !Cs are still needed on twelve parcels. Elevated Amend the Long Completed Thirteen monitoring wells were 11/ 11/2013 concentrations of Term Monitoring added to the LTMP in 2013 and 1,4-dioxane were Plan (LTMP) to are sampled twice a year. detected in Site include further groundwater. sampling of 1,4- Surface water samples collected dioxane in from outfall location DSN00 I, groundwater and where the stream daylights perform an downgradient of the LC/GES, evaluation of its were non-detect for 1,4-dioxane potential impacts to in September 2015 and again in human health and November 2017. the environment. Impacts to human health and the environment were evaluated duri n1r this FYR. IV. FIVE-YEAR REVIEW PROCESS Community Notification, Involvement & Site Interviews On February 16, 2018, EPA Region 1 issued a press release indicating that it would be reviewing cleanups and remedies at 24 Superfund sites in New England, including Laurel Park, Inc. (https://semspub.epa.gov/work/01/623998.pdf}. In addition to this announcement, a notice of the start of 12 this FYR was posted on EPA Region l 's website and sent to local public officials. The purpose of the public notice was to inform the community that EPA would be conducting a FYR to ensure that the remedy implemented at the Site remains protective of public heath and the ~nvironment and is functioning as designed. The notice included contact names and telephone numbers for anyone with questions about the Site or to request to be interviewed as part of the FYR process. The results of the review and the report will be posted to www.epa.gov/superfund/laurelpark and made available at these information repositories: EPA Region I Records Center 5 Post Office Square, l st floor Boston, MA 02109 617-918-1440 (by appointment) Howard Whittemore Memorial Library 243 Church Street Naugatuck, CT 06770 In addition, efforts will be made to reach out to stakeholders and local public officials to inform them of the results. Site Interviews During the FYR process, interviews were primarily conducted by ZaNetta Purnell, Community Involvement Coordinator, to document any perceived problems or successes with the remedy that has been implemented to date. The results of these interviews are summarized below. • On May 15, 2018, an abutting property owner who has been involved with the Site prior to it being listed on the National Priorities List was interviewed. This individual suggested having fewer meetings and doing more door-to-door outreach if conditions were to change at the Site. A concern in regards to soil in the community gardens near the dog park by Andrews Mountain/Rubber A venue (which is off site) was expressed. Nothing is growing in the area and the interviewee is concerned that without sufficient testing, the process of digging in the soil and fertilizing it has the potential to spread contamination, if present. The individual also expressed concerns over a proposal for 300 new homes and solar panels to be built near the Site. • On May 16, 2018, simultaneous interviews were conducted with Naugatuck Mayor Pete Hess, Jim McGrath (Chairman, Naugatuck Water Pollution Board), and Jim Stewart (Director of Public Works). They all feel that EPA has done a great job keeping the town informed. There is significant interest by the town to construct a solar farm on the (privately-owned) landfill which would be a benefit to the town with regard to added revenue. • On May 16, 2018, Ramin Ansari, the contact for the Laurel Park Coalition, was interviewed by telephone. His primary concern is how the emerging contaminants per- and polyfluroalkyl 13 substances ( collectively referred to as "PFAS") will affect the response actions required for the Site. • On June I 5, 2018, Sheila Gleason, CT DEEP's project manager, was interviewed by telephone. She expressed no concerns and feels that she has ample information to be able to answer any questions in regards to the Site. CT DEEP intends to request that the LPC add periodic PFAS sampling in leachate to their monitoring program. • On July 6, 2018, Karen Lumino spoke with Laurel Shaw of the Naugatuck Valley Health District. They have no water quality test results on file from the private water supply well in use at the one residential property that is within a 1,000 ft radius of the Site, and where the homeowner has opted not to tie into the existing public water line. Data Review As part of the review, EPA evaluated the data collected by the LPC between 2013 and 2017 to assess whether contaminants within the landfill continue to be contained by the cap and leachate collection system, and, whether the contaminant concentrations have met the ROD cleanup goals. Groundwater monitoring is used to assess whether contaminated leachate continues to migrate from the landfill; whether concentrations of constituents in downgradient wells are increasing, decreasing or remain unchanged; and whether hydraulic containment is being achieved. Monitoring wells are gauged to assess the leachate level and whether the water table remains below the landfill materials. Groundwater is sampled and analyzed two times a year (a reduction from three times a year approved in 2015) for general chemistry, volatile organic compounds, metals and 1,4-dioxane. The PFAS compounds were added to the sampling program in spring 2018. Refer to Figure 2 to locate the Site features discussed below. Landfill Leachate The hydraulic performance standard established in the ROD is satisfied when the water table has been lowered below the waste and the generation of leachate has ceased or been reduced to a minimum due to dewatering of the landfill. Monitoring wells MW-1 and MW-2, located within the landfill footprint, are used to track changes in leachate levels in the landfill over time. Both wells were installed at the deepest parts of the waste, and completed to the interface between the bottom of refuse and top of bedrock. Leachate levels are measured twice a year. MW-2 has been dry since 1998. MW-1 has been replace twice and most recently in 2004 due to the previous wells shearing or collapsing as the contents in the landfill shifted and settled. At the time of its original installation, over 85 feet of leachate was gauged at the MW-1 location. MW-1 has been dry since 2006. 14 Groundwater Extraction System (GES) The 1988 ROD required an upgraded perimeter leachate collection system to extract groundwater in the shallow bedrock and to enhance the perfonnance of the cap in depressing the water table. The flow metering system at the leachate sample station measures the total volume of leachate and groundwater collected from 21 extraction wells, combined. Approximately 50 million gallons of leachate and groundwater have been discharged from the site to the publicly- owned treatment works (POTW) since November 1998 (Table 5). In addition to lowering the water table, another objective of the GES is to remove highly-contaminated groundwater in the shallow bedrock in the immediate vicinity of the landfill. Fifteen of the 21 extraction wells have been fitted with pneumatic pumps that are positioned two feet above the bottom of the well and that have a minimum design capacity of 0.25 gallons per minute (gpm). The remaining six do not have extraction pumps because the 0.25 gpm minimum criterion was not met during the remedial design pump test. They are, however, used for semi-annual water level measurements. Between 2013 and 2017, the GES was 100% operational. Under routine operating conditions, a pump will automatically cycle on when the groundwater level at that location rises more than two feet and will tum off when water level drops below the pump. To better observe the combined influence of the GES on groundwater flows, the LPC conducted water gauging events during April 2018 with all pumps on (Figure 4 ), and three weeks later with all pumps off (Figure 5). Regionally, groundwater flow direction is not impacted by the GES pumping wells. However, in comparing the groundwater contours under the different conditions (in particular, the 690, 680 and 670 foot contours) the GES wells can be seen to have an influence on the leading edge of the groundwater plume. Groundwater Analytical Data Summary The concentration performance standard established in the ROD is satisfied when the concentration of contaminants in groundwater has stabilized due to the reduced generation of leachate. To assist in the evaluation of chemical trends, the LPC perfonned statistical analyses on the 2013-2017 dataset according to methods specified in 40 CFR §264.97(h), and compared groundwater quality data collected from upgradient ("background") wells to downgradient ("compliance") wells at the Site. In addition, RCRA Groundwater Protection Standards (GWPS) must be met at Point of Compliance (POC) wells. The findings are summarized below. Groundwater Contaminant Trends Statistical analyses were applied to data obtained from two background wells (MP-2A, MP-9) and 22 compliance wells that each has a record of MCL exceedances for various constituents (Table 6). MCLs are not available for iron and manganese; these samples were compared to National Secondary Drinking Water Regulations standards as an alternate data screening method. 1,4-dioxane was not included in the trend analysis. 15 Metals • A downward trend in chromium concentrations in several wells (BH-2, BH-7, OW-I, OW-3) located hydraulically downgradient of the landfill. • An upward trend in selenium in two wells (MW-3, OW-I) located near the downgradient perimeter of the capped landfill. • Arsenic concentrations in multiple wells remain elevated above MCLs and GWPS, but no discemable trends. • Manganese trends increased or declined in multiple wells throughout the monitoring network. • No trends were identified in groundwater concentrations for other metals during this evaluation period. • An increase in the benzene trend was noted in PW-1, located north and downgradient of the capped landfill and the groundwater extraction wells. • An increase in the chlorobenzene trend was noted for OW-1, located at the northern perimeter of the landfill. • No trends were identified in groundwater concentrations for other VOCs during this evaluation period. 2017 Groundwater Snapshot The data collected in 20 I 7 from 23 monitoring wells were used to evaluate progress in meeting MCLs as well as other appropriate federal and state standards. Of these, 11 are RCRA POC wells (OW-1 , OW-5, MW-3, BH-7, BH-8, B-5, BH-2, MW-4C, MP-2A, MP-9, MW-18D) established pursuant to the 1988 ROD. The remainder are wells that were subsequently installed to better delineate the downgradient extent of Site COCs. Refer to Figures 6 and 7. Benzene, chlorobenzene, tetrahydrofuran, and 1,4-dioxane continue to be detected most frequently and at concentrations exceeding regulatory standards or criteria. Overall, VOC concentrations in 2017 were consistent with previous sampling events, and the highest concentrations were detected in POC wells OW-1, OW-5, MW-3, BH-7 and BH-8, and, non-POC well PW-1. 1,4-dioxane was detected in nine of 13 wells at concentrations exceeding the Connecticut Department of Public Health (CT DPH) action level for private wells of 3 micrograms per liter (µg/L). Detected concentrations of 1,4-dioxane ranged from 4.3 µg/L at MW-14 to 280 µg/L at OW-1. 16 Iron and/or manganese concentrations continue to exceed the secondary MCL at all wells sampled, except MP-2A (a background well). However, federal secondary MCLs only apply to esthetics (i.e., taste, color and odor) and do not represent health risk-based criteria. In 2017, arsenic concentrations exceeded the MCL of0.01 milligrams per liter (mg/L) at MW-3, BH-8, MW-7 and BH-7. MW-7 also exceeded MCLs for antimony, beryllium, cadmium, and thallium; and exceeded the CT's GA Groundwater Protection Criteria (GWPC) for chromium (total) and silver. Groundwater arsenic concentrations exceeded the Surface Water Protection Criteria (SWPC) of 0.004 mg/Lat OW-1, BH-8, BH-7, MW-3, MW-7, and MW-11. Anaerobic conditions in closed landfills can cause mobilization of naturally occurring arsenic present in underlying soil or rock. A_t other sites where arsenic is present in groundwater, it can emerge at seeps or surface water. Where this has been seen at other landfill sites, the arsenic commonly co-precipitates with iron, forming a solid floe in which the arsenic is not readily bioavailable. Arsenic was not detected in MP-9, which is located near the upgradient perimeter of the landfill, but was detected at MW-7, which is also considered an upgradient well. The results for MW-7 also included exceedances of the SWPC for beryllium, cadmium, copper and silver. These results are unusual for this well based on previous sampling, and may be the result of drought conditions at the time of sampling. Arsenic was not detected in MW-7 in the April 2017 sampling, but this well showed the highest detected concentration of 0.041 mg/L in the November 2017 sampling. Other wells exceeding the SWPC had arsenic concentrations below 0.020 mg/L. While these arsenic values exceed the SWPC, they are well below CT DEEP surface water criteria freshwater chronic value of 0.150 mg/L. Even without dilution with surface water, the detected concentrations should not pose a risk to aquatic life. Emerging Contaminants • In 2013, 1,4-dioxane was added to the list of analytes of 13 bedrock groundwater monitoring wells for semi-annual sampling and the list of parameters for the leachage discharge permit (General Permit for the Discharge ofGroundwater Remediation Wastewater to a Sanitary Sewer, Permit #GGR00J 298). The highest concentrations of 1,4-dioxane are found in landfill perimeter wells (BH-7, BH-8, MW-3, OW-1) that lie within the LC/GES, and, in leachate. However, in the downgradient wells that lie outside the LC/GES (MW-3, MW-10, MW-14, MW-15D, OW-2, PW-1 ), concentrations are an order of magnitude lower and in some locations (MW-9, MW-1 2S, MW-13) are non-detect. There is not an extensive amount of aquatic toxicity information available for 1, 4-dioxane, however EPA Region 5 has recommended an ecological risk screening value of 22,000 ug/L for this chemical. No detected concentrations in Laurel Park wells approach this value, therefore no ecological risk is anticipated from 1,4-dioxane. • In spring 2018, groundwater samples were collected from ten monitoring wells to assess the presence of Per- and Polyfluoroalkyl Substances (PFAS). PFAS was detected at nine of the ten sample locations, including MW-7, an upgradient/background well (Figure 8). EPA's May 2016 Health Advisories and/or CT DPH's December 2016 Drinking Water Action Level were exceeded in samples collected from three landfill perimeter wells (OW-1 , BH-7, BH-8) that are located upgradient of the LC/GES perimeter drain system and historically, have some of the 17 highest total VOC concentrations. This suggests that although there may be an unknown upgradient source of PFAS compounds, PFAS sources are co-located with VOC sources within the landfill. These data further suggest that the LC/GES is able to capture sufficient quantities of groundwater to limit PFAS presence beyond the limit of the capped landfill. Landfill Gas Emissions In 1998, based on a comprehensive landfill gas monitoring study, EPA and CT DEEP made the determination that air emissions from the newly-capped landfill do not pose a threat to human health or the environment and no treatment was required. Periodic ambient air and limited vent monitoring has been conducted in the intervening years. Under the subsequently promulgated Connecticut Air Pollution Regulations, RCSA Section 22a-174-3a, a permit is required for new or modified stationary sources that emit or have the potential to emit 15 tons per year (TPY) or greater of any individual air pollutant, including methane. Under CERCLA, the substantive requirements of the permit are applicable, while a permit itself is not required for Superfund sites. At the request of EPA, the LPC submitted a new sampling and analysis plan (SAP) in July 2018. The 2018 SAP updates the landfill gas/air monitoring plan in use at the Site since 200 I, and requires more comprehensive sampling, including the direct measurement of emissions from all 15 active gas vents at the Laurel Park Landfill. Data collected under this revised SAP, once approved, will be evaluated and compared with applicable air regulations and evaluated for ongoing protectiveness of human health and the environment. Leachate Discharge and Stormwater The Site operates under two permits issued by the CT DEEP. 1. General Permit for the Discharge ofGroundwater Remediation Wastewater to a Sanitary Sewer (Permit #GGR001298). Discharge samples are collected on the first business day of each month and reported in accordance with permit requirements. There have been no exceedances of the general permit limits at any time since the pennit was issued. Concentrations of 1,4-dioxane, which does not have a general permit limit, ranged from 100 µg/L in November 2017 to 480 µg/L in October 2017. 1,4-dioxane concentrations appear to be in an inverse relationship with groundwater elevations, tending to rise when groundwater elevations are lower. 2. General Permit for the Discharge ofStormwater Associated with Industrial Activity (Permit #GSI002397). Stormwater samples are collected from the designated outfall location (DSN00I) quarterly for visual monitoring; assessments are recorded on a visual monitoring checklist which is kept on file with the Stormwater Pollution Prevention Plan. Stormwater samples are collected for analysis on an annual basis and compared to benchmarks. Although not required by the general permit, 1,4-dioxane has been added to the list of parameters and has not been detected. 18 Site Inspection The inspection of the Site was conducted on April 12, 2018. In attendance were: Karen Lumino, EPA Remedial Project Manager ZaNetta Purnell, EPA Community Involvement Coordinator Liyang Chu, Project Manager, Nobis Engineering (EPA oversight support contractor) Christian Falco, Staff Scientist, Nobis Engineering Russ Dirienzo, Associate Vice President, Arcadis (LPC's representative) Andy Romanoff, Arcadis The purpose of the inspection was to evaluate the condition of the landfill and related features, and overall site conditions to assess the protectiveness of the remedy. Landfill Cover The landfill cover appears to be in good condition. At the time of the site visit, vegetation was only approximately four inches tall due to cold temperatures extending into spring, and covered the entirety of the landfill area. No evidence of undesirable vegetation, animals or vandalism (i.e., ruts/tire tracks) were observed. R. Dirienzo noted that in one area of the landfill, the grass had died, likely from drought conditions the previous years, but had been replaced naturally by weeds that helped to stabilize the soil cover. A landscaper who was consulted about reseeding this area had advised that given the slide slopes, it was more beneficial to leave the current vegetation in place since tilling the soil would result in greater slope instability until the new grass grew in. Site Security Fence The security fence appears to be in good condition. Warning signs near the entrance gate appear to be sufficient in number facing outward from the Site. No evidence of vandalism or unauthorized access to the Site through the fence was observed. On-site access gates were locked and in good working order. Run On/OffControl System The control systems appear to be functioning as designed. The gabion and riprap structures appear to be in good condition with few areas of sparse vegetation. At the time of the inspection, no water was observed flowing through the riprap into the runoff areas. No substantial sediment build up in these areas was observed, nor was there evidence of erosion, washout, damage or vandalism. Gas Venting System. Leachate Collection System and Manholes Based on limited observation due to potential health and safety concerns associated with potential air emissions, the gas vents appear to be in good condition. The vents were in an upright position and there was no evidence of vandalism. R. Dirienzo stated that bird screens on the vents are checked monthly and all bird screens were observed to be intact. The signs on the manholes were present. The visible portions of the leachate collection system appeared to be in good condition. 19 Settlement Monitoring No areas of settlement were observed on the day of the inspection. R. Dirienzo stated that the approved O&M plan does not require monitoring or surveying the settlement markers. Groundwater Monitoring System The groundwater monitoring system appeared to be in good condition. Well casings and covers were in acceptable condition. In select areas, minor vegetative growth surrounded the monitoring wells. Some rusting on the outer casing of the monitoring wells was identified. A. Romanoff stated that all groundwater monitoring wells are kept locked. Wetland Area When viewed from the top of the landfill, the wetland area- voluntarily restored by the LPC - appeared to be well vegetated. At lower elevations, the sound of spring peepers resonated loudly. R. Dirienzo stated that the vernal pool was created after the LPC repaired a dam in a retention basin. V. TECHNICAL ASSESSMENT QUESTION A: Is the remedy functioning as intended by the decision documents? Yes. Review of available documents, evaluation of compiled data, and the results of the site inspection indicate that the remedy is functioning as intended in the 1988 ROD. A public water line was completed in the spring of 1989 for residents with private water supplies at risk from contamination. All residents within a 1,000-foot radius of the Site are now served with public water, with one exception. The homeowner of that residence located on Hunters Mountain Road has chosen not to connect to public water; has declined repeated offers by the LPC to sample the private well; and has asked to be left alone. However, this residence is not likely to be impaced by Site COCs, as it is both up- and cross-gradient from the regional northwesterly flow of groudwater. The LPC has been performing all required environmental monitoring and routine site inspections. The results of these activities have been documented and reviewed by EPA and its technical consultant. Review of the records and on-site observations indicate that the cover system, groundwater extraction wells, leachate collection system, gas vent system and monitoring wells all appear to be in good working condition and are well maintained. There is routine flushing of the leachate collection system lines and periodic servicing of the pneumatic pumps so that both systems will be subject to less down time and have more efficient operations. Monthly site inspections performed by Arcadis, on behalf of the LPC, allow frequent assessment of various landfill components so repairs can be performed in a timely manner. There were no issues identified during the site inspection. The multi-layer cap has achieved the specific objectives for reducing infiltration in the landfill so that landfill leachate generation has decreased. The two monitoring wells used to measure leachate levels 20 continue to be dry, indicating that in those two locations, the landfill has been dewatered. There is some degree of uncertainty about whether the last couple feet of the ten-foot screen in the MW-1 replacement well installed in 2004 is damaged at or near the waste/weathered bedrock interface. In order to make a determination in the future regarding the extent to which the water table has been sufficiently lowered below the waste (the hydraulic performance standard), the uncertainty with MW-1 will need to be resolved - either by replacing it, redeveloping it and/or installing a new leachate monitoring well(s). In the interim, groundwater VOC and metal data collected from wells located outside of the landfill can provide an indirect indication of when landfill wastes are no longer saturated. Once VOCs and metals concentrations have declined to below cleanup standards, this would indicate no further leaching of landfill wastes or that the wastes have been dewatered. The LC/GES have reduced the release or migration of contaminants to other environmental media and have prevented direct contact with or ingestion of contaminants. However, review of records indicates that contaminated groundwater is still migrating past the LC/GES as evidenced by VOC, metals and 1,4- dioxane detections exceeding standards in downgradient bedrock wells located north and east of the landfill, and, in the overburden aquifer unit, as evidence by benzene and 1,4-dioxane in MW-15D. Statistical analysis for groundwater metals data exceeding the MCLs during the past five years indicate that there were downward trends for chromium concentrations in some wells while selenium concentrations generally increased in other wells. Manganese concentration trends have both increased and decreased for multiple wells. Statistical analysis of benzene and chlorobenzene concentrations exceeding the MCLs indicate upward trends in two monitoring wells located downgradient of the capped landfill. Arsenic concentrations in multiple wells continue to exceed MCLs, but no trends were discernible. 1,4-dioxane was not included in the statistical analysis, however, the frequency of detections of this contaminant that exceed CT DPH's action level (3 ug/L) has not decreased over the past five years. The LC/GES has been effective in capturing large quantities of contaminated overburden and shallow bedrock groundwater and preventing off-site contaminant migration at concentrations exceeding groundwater cleanup standards and is expected to continue doing so. Comparing the data collected from OW-1, which is inside the LC/GES, to OW-2, which is outside and downgradient of the influence of the LC/GES, demonstrates this quite clearly (see Figure 7). However, due to the complex hydrogeology of the Site which is further complicatd by the fact that the landfill waste is either sitting directly on or in close proximity to weathered, highly fractured shallow bedrock, it is not possible to ensure complete capture of all contaminated groundwater in the deeper bedrock aquifer. For this reason, the remedy relies on institutional controls (e.g., ordinances, land use restrictions, deed notices) to restrict the use of groundwater. Efforts to implement !Cs to restrict the use of contaminated groundwater and to protect the landfill and the remediation components from any unauthorized disturbance have been initiated by the LPC. ICs have been implemented on two parcels owned by the LPC, as land use restrictions have been recorded for those properties. Discussions regarding land use restrictions with the remaining property owner of parcels that require institutional controls are ongoing, and progress is being made toward finalization of the remaining ICs required at the Site. 21 QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels, and remedial action objectives (RAOs) used at the time of the remedy selection still valid? Question B Summary No. There have been changes to the toxicity values, exposure assumptions, exposure pathways and methods of evaluating risk since the 1988 ROD. However, the RAOs selected for the site are still valid. The ROD established groundwater cleanup criteria based on RCRA GWPS. The vapor intrusion pathway was not evaluated in the original human health risk assessment, but has been identified as a potential pathway of exposure. Additionally, emerging contaminants including l ,4-dioxane and PFAS have been identified since the remedy selection. Institutional controls prohibiting groundwater use as drinking water at neighboring properties are only partially in place and bedrock groundwater concentrations along the perimeter of the capped landfill exceed drinking water standards. However, an alternate water source is available, minimizing potential exposure. Although the remedy was not designed to be protective of vapor intrusion, this pathway is incomplete under current Site-use conditions, therefore would not pose an additional risk to human health. The changes as described below are not expected to alter the protectiveness of the remedy because residences in the area are serviced by a public water supply and are not exposed to affected groundwater. Changes in Standards and TBCs In general, changes in standards since the 1988 ROD do not change the protectiveness of the remedy. • Resource Conservation and Recovery Act (RCRA) Part 264. The landfill cap and all subsequent repairs and modifications to the cap were designed in accordance with applicable RCRA requirements. EPA approved the cap on July 24, 1998, and the LPC continues to perform O&M as necessary. Groundwater monitoring is performed in accordance with the RCRA GWPS specified in 40 CFR 264.97. • Clean Water Act. Leachate from the landfill is directed to the NaugatuckWater Pollution Control Facility where it is commingled with other wastes, then treated in accordance with regulatory criteria (i.e., NPDES permit). • Clean Air Act and Connecticut Air Regulations. Air pollution regulatory authority has been delegated to the State of Connecticut. New applicable and relevant and appropriate requirements (ARARs) have been promulgated since the 1988 ROD, including Connecticut Air Pollution Regulations regulating new or modified stationary sources that emit or have the potential to emit 15 TPY or more of any individual air pollutant. Once the July 2018 SAP is approved, data collected in accordance with the new plan will be evaluated and compared with applicable air regulations and evaluated for ongoing protectiveness of human health and the environment. 22 • Safe Drinking Water Act; EPA Groundwater Protection Strategy. New ARARs have been promulgated since the 1988 ROD which include MCLs and non-zero Maximum Contaminant Level Goals. However, these changes do not affect the protectiveness of the remedy because the remedy currently relies on providing an alternate safe drinking water source and institutional controls (where they have been recorded). • Connecticut Remediation Standard Regulations (RSRs); Groundwater Protection Criteria (GWPC). GWPC, which identify the numeric chemical concentrations to be attained for groundwater plume remediation in aquifers with GA and GB classifications (groundwater that is currently known or presumed to be degraded, and is either being used or could be used in the future as a drinking water source) have been promulgated since the 1988 ROD. Bedrock groundwater is sampled, analyzed, and evaluated against the RSR GWPC under the Site's long-term monitoring plan. These newly-promulgated criteria do not affect the protectiveness of the remedy because the remedy currently relied on providing an alternate safe drinking water sourc and institutional controls (where they have been recorded). • Connecticut RSRs; Surface Water Protection Criteria (SWPC). For a groundwater plume that discharges to a surface water body, the plume needs to attain the numerical limits established under the SWPC, which were promulgated since the 1988 ROD. Because groundwater discharges to an unnamed stream in the vicinity of the landfill, it is possible that some groundwater contaminants are migrating into this surface water body. There have been no changes to applicable ecological risk standards for arsenic in groundwater since the last FYR. For 1,4-dioxane, the only ecological screening value available is from a set of screening benchmarks produced by the EPA Region 5 RCRA program in 2003 (https://archi ve.epa. gov/region5/waste/cars/web /pdf/ecological screening-levels-200308. pdt) This value is 22 mg/kg which is orders of magnitude higher than any concentration detected in groundwater at Laurel Park Landfill. • Connecticut RSRs; Volatilization Criteria (VC). Groundwater containing VOCs within 15 feet of the ground surface or an occupied industrial or residential structure needs io comply with VC, which were promulgated since the 1988 ROD. The on-site compressor/equipment building is equipped with an alarmed meter that monitors for methane continuously. Unsafe levels of methane have never been detected in the building. Changes in Toxicity and Other Contaminant Characteristics Since the time of the original endangerment assessment performed as part of the RI, EPA has re examined and updated toxicity factors for each of the indicator contaminants evaluated. Additionally, information on emerging contaminants including 1,4-dioxane and PFAS has become available. Changes in these toxicity factors do not affect the protectiveness of the remedy because of its reliance on an 23 alternate safe drinking water source, and prevention of direct contact with soil, which minimizes the impacts of updated toxicity factors. • 2016 PFOA/PFOS non-cancer toxicity values In May 2016, EPA issued final lifetime drinking water health advisories for PFOA and PFOS, which identified a chronic oral reference dose (RID) of 2E-05 mg/kg-day for PFOA and PFOS (USEPA , 2016a and USEPA , 2016b) . These RID values should be used when evaluating potential risks from ingestion of contaminated groundwater at Superfund sites where PFOA and PFOS might be present based on site history. Potential estimated health risks from PFOA and PFOS, would likely increase total site risks due to groundwater exposure, however there is no current exposure to affected groundwater. Further evaluation of potential risks from exposure to PFOA and PFOS in other media at the Site might be needed based on site conditions and can also affect total site risks. • 2014 PFBS non-cancer toxicity value PFBS has a chronic oral RID of2E-02 mg/kg-day based on an EPA Provisional Peer Reviewed Toxicity Value (USEPA, 2014c). This RID value should be used when evaluating potential risks from ingestion of contaminated groundwater at Superfund sites where PFBS might be present based on site history. Potential estimated health risks from PFBS would likely increase total site risks due to groundwater exposure, however there is no current exposure to affected groundwater. Further evaluation of potential risks from exposure to PFBS in other media at the Site might be needed based on site conditions and can also affect total site risks. PFOA, PFOS, and PFBS belong to a group of compounds known as PFAS , which are used in a variety of industrial applications. Sampling was requested at Laurel Park because PFAS compounds are commonly associated with landfills containing industrial and chemical waste. Plans to sample were approved by EPA Headquarters and sampling was carried out in the spring of 2018. The data showed some exceedances of site-specific groundwater screening levels for PFOA in wells OW-1 and BH-7. Residences in the area have been connected to a municipal water source, therefore there would not be any exposure to PFAS contamination under current Site conditions. These new toxicity values do not affect the current protectiveness of the remedy, however, PFAS should be included as a follow up item in the next FYR period to ensure there are no unacceptable risks in the future. • 2013 1,4-dioxane cancer and non-cancer toxicity values No new contaminant sources have been identified since the startup of the remedy, however one new contan1inant of potential concern was identified during the previous FYR period: elevated oncentrations of 1,4-dioxane were detected in Site groundwater in August 2013 and in 2016-2017. This compound was commonly used as a chlorinated solvent stabilizer to prevent product degradation. Its presence at the site does not pose any additional threat to human health due to the use of an alternate drinking water source. The one home with a private supply well located 1,000 feet from the Site has refused the offers of the LPC to test her well for Site COCs. This property, located on Hunters Mountain Road, is not 24 likely to be impacted by the Site as it is both up- and cross-gradient of the northwesterly direction of regional groundwater flow. In 2013, EPA revised the toxicity values for 1,4-dioxane. The oral slope factor increased, while the value for inhalation unit risk decreased, which indicates that 1,4-dioxane is more toxic from cancer health effects via the oral pathway, but less toxic from inhalation. Additionally, the non-cancer values for oral reference dose and inhalation reference concentration both decreased, which indicates that 1,4- dioxane is more toxic from non-cancer hazards. Changes in risk assessment methods • 2014 OSWER Directive Determining Groundwater Exposure Point Concentrations, Supplemental Guidance In 2014, EPA finalized a Directive to determine groundwater exposure point concentrations (EPCs), available at https://v,rww.epa.gov/sites/production/files/2015-09/documents/exposme point cone. pdf (USEP A, 2014b). This Directive provides recommendations to develop groundwater EPCs. The recommendations to calculate the 95% UCL of the arithmetic mean concentration for each contaminant from wells within the core/center of the plume, using the statistical software ProUCL could result in lower groundwater EPCs than the maximum concentrations routinely used for EPCs as past practice in risk assessment, leading to changes in groundwater risk screening and evaluation. In general, this approach could result in slightly lower risk or lower screening levels. • 2014 OSWER Directive on the Update ofStandard Default Exposure Factors In 2014, EPA finalized a Directive to update standard default exposure factors and frequently asked questions associated with these updates, available at https://www.epa.gov/sites/production/fi les/2015- 11/documents/oswer directive 9200.1 -120 exposurefactors corrected2.pdf (items# 22 and #23 of this web link) (USEPA, 2014a). Many of these exposure factors differ from those used in the risk assessment(s) supporting the ROD(s). These changes in general would result in a slight decrease of the risk estimates for most chemicals. • 20J 5 OSWER Directive on the Update ofStandard Default Exposure· Factor Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subswface Vapor Sources to Indoor Air In June 2015, EPA finalized the Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air and updated the vapor intrusion screening levels (VISLs) electronic calculator to develop media-specific risk-based VISLs for groundwater, soil gas, and indoor air. These VISLs, which are periodically updated, can be found at the EPA vapor intrusion web page (http:/ /www.epa . gov/ oswer/vaporintrusion/ guidance. htm l#Item6). 25 • EPA Regional Screening Levels EPA updates Regional Screening Level tables twice a year and the most current ones are available at the EPA Regional Screening Levels web page (http://www.epa.gov/reg3hwmd/risk/human/rb concentration tableO. Changes in Exposure Pathways The exposure pathways considered in the Endangerment Assessment performed during the 1987 RI included: (1) ingestion of groundwater; (2) ingestion of soil by small children; and (3) direct exposures to sediment and surface water. With the completion of the landfill cap, leachate collection system, and security fence, each of these pathways except the ingestion of groundwater pathway, is no longer applicable. Institutional controls prohibiting groundwater use as drinking water at neighboring properties have not been fully implemented. However, public water is available, which prevents exposure to site impacted groundwater. Vapor Intrusion The vapor intrusion (VI) pathway was not evaluated in the original public health and environmental assessment. In accordance with EPA guidance, the potential for vapor intrusion is evaluated at the Site during each FYR period; the first such evaluation was completed in 2013. For the 2013 FYR, groundwater data were reviewed for potential VI issues. Comparison of the 2011 and 2012 groundwater data from both overburden and bedrock wells to EPA 2012 VISLs based on protection ofresidential indoor air (based on 1 x 10-6 cancer risk and hazard quotient of 1) indicated benzene was present at concentrations exceeding screening levels at bedrock wells OW-I, OW-2, OW-5, PW-1, MW-15O, MW-3, BH-7, BH-8, BH-2, and MP-9. Ethyl benzene was also present at concentrations exceeding screening levels at OW-1 and OW-5. Most of the VISL exceedances were located inside the ring of extraction wells or just to the north, away from residences. For the 2018 FYR, groundwater data were again reviewed for any potential VI issues. The most recent annual monitoring report ( fall 20 I 7) showed a few exceedances of EPA target groundwater V OC concentrations for the VI pathway including benzene, chlorobenzene and TCE, however because there are no potential receptors (i.e., buildings) in the area where vapor-forming chemicals are present in the subsurface, the vapor intrusion exposure pathway at the Site is incomplete under current site-use conditions. Continued monitoring of shallow groundwater data with comparison of data to EPA VISLs is recommended to assure the protectiveness of the remedy. Additionally, if site conditions change in the future, the VI pathway may need to be re-evaluated. Expected Progress Towards Meeting RA Os The landfill cap, leachate collection system, and shallow groundwater extraction system have reduced the release of contaminants from the landfill to groundwater, surface water, sediments, soils and air. Capping and fencing are preventing potential direct human contact with contaminated soils in the source area. The availability of public water since 1989 to nearby homes has reduced exposures to groundwater 26 as the primary drinking water source at all but one residence (at the homeowner's choosing). This property is up- and cross-gradient from the northwesterly regional flow of groundwater and it not likely to be impacted by Site COCs. Although the water table underlying the landfill has been shown to be lowered in the two locations where leachate levels are gauged, it is unclear whether the groundwater level has been completely lowered to below the landfill waste to prevent further release of leachate to groundwater. While most of the contaminated groundwater migrating from the landfill has been captured by the LC/GES, some contaminated groundwater is still migrating downgradient beyond its influence. While contamination is migrating beyond the point of compliance at concentrations exceeding cleanup standards, there have been no detections above acceptable standards at the furthest downgradient wells. However, these low detections confirm that there is limited groundwater migration of Site contaminants to the edge of the plume. Institutional controls prohibiting groundwater use as drinking water at the Site have not been fully implemented. · QUESTION C: Has any other information come to light that could call into question the protectiveness of the remedy? No. VI. ISSUES/RECOMMENDATIONS OU(s) without Issues/Recommendations Identified in tlte Five>-Year Rev:iew: None Issues and Recommend.ations Identified in the Five-Year Review: OU(s): Entire Issue Category: Institutional Controls Site Issue: Not all ICs have been implemented. Recommendation: Complete implementation of all I Cs. Affect Current Affect Future Party Oversight Party Milestone Date Protectiveness Protectiveness Responsible No Yes PRP EPA/State 9/20/2020 27 OTHER FINDINGS The following items were identified during the FYR and may add to the understanding of Site conditions and progress towards meeting the RAOs, but do not affect current and/or future protectiveness: • Periodic shut down of the groundwater extraction system for a short duration (i.e., 12 - 24 hours) to measure directly the amount of leachate being generated, vis-a-vis the hydraulic performance standard. • Prior to performing the groundwater statistical analysis for the 2023 FYR, it is recommended that EPA and the LPC review the list of parameters to be included (e.g., add 1,4-dioxane and other constitutents that exceed CT RSRs; remove iron) and clarify which wells represent background. • MW-7 is an upgradient, background well. Collect filtered samples for dissolved metals analysis along with an unfiltered samples for total metals to determine whether suspended solids are contributing to the recent detection of metals at this location. • Continue to sample for PFAS compounds in the locations sampled in spring 2018, with the addition ofMW-1 3. Conduct sampling in fal l 2018 and annually after that. Sample periodically for PFAS compounds in leachate prior to discharge to the Naugatuck POTW. • MW-11 A, the bedrock well that is furthest downgradient of the Site, was removed from the long term monitoring plan at the request of a previous landowner. Approach the new landowner for a one-time sampling event for VOCs (benzene in particular), 1,4-dioxane and PFAS compounds. • Complete review of new landfill gas emissions SAP. Once approved, LPC will collect samples for comparison to applicable air regulations to evaluate ongoing protectiveness of human health and the environment. VII. PROTECTIVENESS STA TEMENT Sitewide Protecth·eness Statement Protectiveness Determination: September 2018 Short-term Protective Protectiveness Statement: The remedy is currently protective of human health and the environment in the short-term because: (I) the cap is preventing direct contact exposures to landfill contaminants and minimizes contaminant migration; (2) the leachate collection and groundwater extraction system is containing the majority of groundwater contaminants on-Site; and (3) the waterline installed along Hunters Mountain Road helps to ensure that adjacent residents are not exposed to potential Site groundwater contamination. However, in order for the remedy to be protective in the long-term, remaining institutional controls must be finalized. 28 VIII. NEXT REVIEW The next five-year review report for the Laurel Park Inc Superfund Site is required five years from the completion date of this review. 29 APPENDIX A - REFERENCE LIST Arcadis, 2014. 2013 Annual Monitoring Report, Laurel Park Landfill Site, Naugatuck, CT. May. Arcadis, 2015. 2014 Annual Monitoring Report, Laurel Park Landfill Site, Naugatuck, CT. May. Arcadis, 2016. Semi-Annual O&M Report, Second Half 2015, Laurel Park Landfill Site, Naugatuck, CT. February. Arcadis, 2017. Semi-Annual O&M Report, Second Half 2016, Laurel Park Landfill Site, Naugatuck, CT. March. Arcadis, 2018. Semi-Annual O&M Report, Second Half 2017, Laurel Park Landfill Site, Naugatuck, CT. February. Arcadis, 2018. Five-year Review Statistical Report, Groundwater Data, 2013 - 2017, Laurel Park Landfill Site, Naugatuck, CT. May. Arcadis, 2018. 5 Year Review Groundwater Extraction System Evaluation and PFAS Data Summary, Laurel Park Landfill Site, Naugatuck, CT. June. Carroll, C. Site-specific Screening Levels for groundwaterfor PFOA, PFOS, and PFBSfor the Laurel Park NPL Site. [Memorandum]. February 13, 2018. USEPA, 2001. Comprehensive Five-Year Review Guidance. OSWER 9355.7-03 B-P. June. USEPA, 2014a. Human Health Evaluation Manual, Supplemental Guidance: Update ofStandard Default Exposure Factors. OSWER Directive 9200. 1-120. February. USEPA, 2014b. Determining Groundwater Exposure Point Concentrations. OSWER Directive 9283 .1-42. February. USEPA, 2014c. Provisional Peer-Reviewed Toxicity Values for Perfl.uorobutane Sulfonate CASRN 375- 73-5) and Related Compound Potassium Perjl.uorobutane Sulfonate (CASRN 29420-49-3). U.S. Environmental Protection Agency, Office of Research and Development: Cincinnati, OH. USEPA, 2016a. Drinking Water Health Adviso,yfor Perjl.uorooctanoic Acid (PFOA). U.S. Environmental Protection Agency, Office of Water: Washington, DC. EPA 822-R-16-005. May. USEPA, 2016b. Drinking Water Health Advis01y for Perfl.uorooctane Sulfonate (PFOS). U.S. Environmental Protection Agency, Office of Water: Washington, DC. EPA 822-R-16-004. May. USEPA, 2016c. Transmittal ofthe Five-Year Review Recommended Template. OLEM 9200.0-89 [Memorandum]. January. 30 APPENDIX B -ADDITIONAL DATA TABLES AND FIGURES 31 TABLE 5 LEACHATE FLOW RATES NOVEMBER 1998 THROUGH DECEMBER 2017 LAUREL PARK LANDFILL NAUGATUCK, CONNECTICUT 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 Month Gallons per Gallons per Gallons per Gallons per Gallons per Gallons per Gallons per Gallons per Gallons per Gallons per month month month month month month month month month month Januarv 114,774 94,712 245,248 654,382 183,759 122,568 135,146 202,502 198,977 192,584 Februarv 109,903 158,220 191,863 99,299 155,634 124,510 153,624 174,538 162,573 279,502 March 89,814 125,786 310,154 128,446 253,209 111,729 279,511 239,289 185,352 336,040 Aorll 163,092 113,360 322,368 247,794 143,557 164,164 241,314 177,894 195,673 255,344 Mav 163,011 115,831 211,157 260,839 134,780 230,182 280,263 126,907 167,780 197,864 June 106,178 81 ,036 243,543 178,862 281,756 239,229 217,318 116,723 179,223 194,011 Julv 79,585 48,365 86,284 159,440 288,455 261,026 168,793 113,430 149,613 184,405 Auaust 57,151 121,271 109,328 92,505 214,606 146,410 180,231 115,993 164,322 164,873 Seotember 49,453 73,049 115,593 110,884 112,720 131 ,883 235,594 103,010 112,445 178,018 October 79,780 39,547 39,393 210,346 48,101 139,830 179,008 166,903 143,086 162,167 November 89,423 84,113 57,916 251 ,580 79,636 127,459 188,467 168,251 185,315 244,919 December 82,868 75,542 77,679 313,154 308,747 154,399 191,428 199,621 236,766 286,281 Total Gallons 1,185,032 1.~30 832 2,010,526 2,707,531 2.2M'.960 1,953,389 2 450,697, 1 905,061 2,081,125 ,2,676,008 I 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 Month Gallons per Gallons per Gallons per Gallons per Gallons per Gallons per Gallons per Gallons per Gallons per Gallons per month month month month month month month month month month Januarv 332,211 498,534 298,260 277,387 391,878 147,478 244,389 492,156 299,039 - February 231,833 358,446 314,189 295,137 209,891 177,410 282,324 316,985 315,166 - March 314,510 353,513 519,100 448,254 328,888 225,275 416,330 279,129 406,451 - Aoril 277,301 247,943 651 ,791 495,419 300,212 199,114 384,512 369,547 141,441 -- Mav 183,050 308,956 559,264 444,533 328,844 239,066 338,330 398,035 256,760 - June 126,594 338,338 156,492 223,695 582,837 202,515 279,550 311,207 156,044 -- Julv 132,953 348,073 147,395 134 174 220,085 133,408 155,457 423,439 89,280 -- Auaust 142,341 289,083 148,841 95,390 300,938 133,738 151,316 404,315 67,516 -- Seotember 103,620 211 ,957 148,076 108,698 254,719 162,563 138,128 314,293 125,504 -- October 99,046 238,260 251,799 186,290 299,893 212,854 205,692 355,096 282,565 -- November 135.412 332,870 309,688 196,248 303,385 315,427 187,793 126,710 244,040 226,936 December 183,881 299,405 421 ,557 313,415 199,763 302,544 88,060 241 ,658 305,363 230,891 :rotal Gallons ~262 7.52 ' 3 825,378 II 3,926452 3 218640 . '3 721 333 2 451392 2 871 881 4 032,570 2 689169 457 827 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 ~ ARCADIS I=.='~ Table 6. Summary of 2013 . 2017 Data Availability, USEPA MCL Exceedances, and Statistical Analyses Performed Well ID Date Data Avallablllty USEPA MCL Exceedances Statlsllcal Analysis NORTHERN LANDFILL AREA 41112013 Sampled Iron Manganese 8/112013 Sampled (1,4-Dloxane Only) None 11112/2013 Samoled Iron Manaanese 4122/2014 Samoled Iron Manoanese 8/20/201 4 Samoled (1,4-Dloxane Only) None 11/12/2014 Samoled Iron Manoanese Conducted f0< iron and MW-14 4122/2015 Samoled Iron Manaanese manganese. 11/1112015 Samoled Iron Manaanese 4/13/2016 Sampled Iron Manganese 11/17/2016 Sampled Iron Manganese 4/19/2017 Sampled Iron Manganese 8/2/2017 Samoled (1,4-Dioxane Only) None 11/16/2017 Samoled Iron Manaanese 4/1/2013 Sampled None 8/1/2013 Sampled None 11112/2013 Samoled Iron Manaanese 4/22/2014 Samoled Manaanese 8/2112014 Sampled Iron Manaanese 11/12/2014 Samoled Iron Manaanese Conducted for Iron and MW-15D 4/22/2015 Sampled Manaanese manganese. 11/ 12/2015 Samoled Iron Manaanese 4/12/2016 Sampled Iron Manaanese 11/ 18/2016 Sampled Iron Manaanese 4/19/2017 Sampled Iron Manaanese 8/2/2017 Sampled (1,4-Dloxane Only) None 11116/2017 Sampled Iron Manaanese 41112013 Samoled Benzene, Iron, Manganese 8/1/2013 Samoled Benzene Iron Manganese 11112/2013 Samoled Benzene Iron Manganese Benzene, Chlorobenzene, Iron, 4/22/2014 Sampled Manganese Benzene, Chlorobenzene, Iron, 8/21/2014 Sampled Manaanese Benzene, Chlorobenzene, Iron, 11/14/2014 Sampled Manganese Benzene, Chlarobenzene, 4/24/2015 Sampled Conducted for arsenic. Chromium (total), Iron, Manganese benzene, chlorobenzene, OW-1 chromium (tolaQ, Iron, Arsenic, Benzene, Chlorobenzene, manganese. sele nium. end vlnyt 11/13/2015 Sampled Iron, Manganese, Selenium, Vinyl chloride. Chloride 4/1512016 Sampled Chlorobenzene, Iron, Manganese 11/21/2016 Samoled Benzene Iron Manganese Benzene, Chlorobenzene, Iron, 4/21/2017 Sampled Manganese 8/2/2017 · Samcled (1 4-Dioxane Only) None Benzene, Chlorobenzene, Iron, 11117/2017 Sampled Manaanese 4/1/2013 Same led Iron Manganese 8/1/201 3 Samoled Iron Manganese 11/12/2013 Samoled Iron Man aanese 4/22/2014 Samoled Iron Manganese 8/20/2014 Samoled Iron Manganese 11/14/2014 Sampled Iron Manganese Conducted for iron and OW-2 4/24/2015 Sampled Iron Manganese manganese. 11112/2015 Sampled Iron Manganese 4/15/2016 Sampled Iron Manganese 11/21/2016 Sampled Iron Manganese 4/20/2017 Sampled Iron Manganese 8/2/2017 Samoled (1 ,4-Dioxane Only) None 11117/2017 Sampled Iron Manaanese 4/1/2013 Samoled Iron Manaanese 8/1/2013 NS NA 11112/2013 Samoled Iron Manaanesa 4/22/2014 Sampled Chromium (total), Iron, Manganese 8/19/2014 NS NA 11/13/2014 Samoled Conducted f0< chromium (lotal), OW-3 Iron Manaanese Iron. and manganese. 4/24/2015 Sampled Chromium (total), Iron, Manganese 11/11/2015 Sampled Iron Manaanese 4112/2016 Sampled Iron Manganese 11118/2016 Samoled Iron Manaanese 4/20/2017 Samoled Iron Manganese 11115/2017 Samoled Iran Manoanese Page 1 of 5 Table 6. Summary of 2013. 2017 Data Avallablllty, USEPA MCL Exceedances, and Statistical Analyses Performed Well ID Date Data Availability USEPA MCL Exc&edances Statlstlcal Analysis 4/1/2013 Sampled Manganese 8/1/2013 Samoled Iron Manaanese 11/1V20l 3 DRY NA 4/22/2014 Saml)led Manaanese 8/20/2014 Sampled Manaanese 11/10/2014 DRY NA Conducted ror Iron and OW-4 4/24/2015 Samoled Manaanese manganese. 11/11/2015 DRY NA 4115/2016 Samoled Manoanese 11/15/2016 DRY NA 4/20/2017 Sampled Manaanese 11/17/2017 Sampled Iron Manaanese 4/1/2013 Sampled Benzene, Iron 8/1/2013 Sampled Benzene Iron Manoanese 11/1V2013 Samoled Benzene Iron Manganese 4/22/2014 Samoled Benzene Iron 8/21/2014 Sampled Benzene Iron Manganese 11/14/2014 Sampled Benzene Iron Manaanese Conducted ror benzene. Iron, OW-5 41241201 5 SamDled Benzene Iron Manoanese and manganese. 11/13/2015 Samoled Benzene Iron Manoanese 4/1512016 Samoled Benzene Iron Manoanese 11/21/2016 Samoled Benzene Iron Manoanese 412112017 Samoled Benzene Iron Manoanesa 11/17/2017 Sampled Benzene Iron Manoanese 4/1/2013 Sampled Iron, Manaanese 8/1/2013 Samoled Iron Manaanese 11/1V2013 Samoled Benzene Iron Manoanese 412V2014 Samoled Benzene Iron Manaanese 8/2012014 Same ed Benzene Iron Manaanese 11/13/2014 Same ed Benzene Iron Manoanese Conducted ror benzene. Iron, PW-1 4123/2015 Same ed Manoanese and manganese. 11/1V2015 Same ed Benzene Iron Manaanese 4112/2016 Same ed Benzene Iron Manoanese 11/18/2016 Same ed Benzene Iron Manaanese 4/20/2017 Samoled Benzene Iron Manoanese 8/2/2017 Samoled /1.4-Dioxane Onlv\ None 11116/2017 Samoled Benzene Iron Manaanesa EASTERN LANDFILL AREA 41112013 Sampled Benzene, Iron, Manganese Arsenic, Benzene, Chlorobenzene, 8/1/2013 Sampled Chromium (total), Iron, Manganese 11112/2013 Sampled Arsenic, Benzene, Iron, Manganese 4/2V2014 Samoled Benzene Iron Manaanoso 8/19/2014 Sampled Benzene Iron ManQanese 11112/2014 Sampled Arsenic, Benzene, Iron, Manganese Conducted ror arsenic. 4123/2015 Samoled Benzene Iron Manaanese benzene. cl'llorobenzenc. BH-7 Arsenic, Benzene, C hlorobenzene, cl'lromium (lolal). Iron, 11111/2015 Sampled Iron, Manganese, Selenium manganese, and selenium, Benzene, Chlorobenzene, Iron, 4/13/2016 Sampled Manaanase Arsenic, Benzene, Chlorobenzene, 11117/2016 Sampled Iron, Manganese, Selenium 4/1912017 Samoled Benzene Iron Manaanese 8/2/2017 Sampled 11.4-Dioxane Onlvl None Benzene, Chlorobenzene, Iron, 11/15/2017 Sampled Manaanese 4/112013 Sampled Arsenic, Benzene, Iron, Manganese 81112013 Sampled Arsenic, Benzene, Iron, Manganese 11/1V2013 Sampled Arsenic, Benzene, Iron, Manganese 4122/2014 Sampled Arsenic, Benzene, Iron, Manganese 8/1912014 Sampled Arsenic, Benzene, Iron, Manganese Conducted for arsenic. BH-8 11/1112014 Sampled Arsenic, Benzene, Iron, Manganese benzene. iron. and manganese. 412V2015 Samoled Arsenic Iron Manoanese 11/1112015 Sampled Arsenic, Benzene, Iron, Manganese 4112/2016 Sampled Iron Manoanese 11/16/2016 Sampled Arsenic, Benzene, Iron, Manganese 4118/2017 Samoled Iron Manaanese 8/2/2017 Samoled I1.4-Dioxane Only) None 11/15/2017 Sampled Arsenic, Benzene, Iron, Manganese Page 2 or 5 Table 6 - Summary of 2013 - 2017 Data Avallabillty, USEPA MCL Exceedances, and Statistical Analyses Performed Well ID Date Data Availability USEPA MCL Exceedances Statistical Analysis 4/1/2013 Sampled Arsenic, Benzene, Iron, Manganese 8/1/2013 Sampled Arsenic, Benzene, Iron, Manganese 11/12/2013 Sampled Arsenic, Benzene, Iron, Manganese 4/22/2014 Sampled Arsenic, Benzene, Iron, Manganese 8119/2014 Sampled Arsenic, Benzene, Iron, Manganese 11/12/2014 Sampled Arsenic Iron Manganese Conducted for arsenic, MW-3 benzene, Iron, manganese. and 4/23/2015 Sampled Arsenic, Benzene, Iron, Manganese selenium. Arsenic, Benzene, Iron, Manganese, 11/11/2015 Sampled Selenium 4/13/2016 Sampled Arsenic, Benzene, Iron, Manganese 11117/2016 Sampled Arsenic, Benzene, Iron, Manganese 4/19/2017 Sampled Arsenic, Benzene, Iron, Manganese 81112017 Sampled (1.4-Dioxane Only) None 11115/2017 Samoled Benz.en• Iron Manganese 411/2013 Sampled Iron Manganese 811/2013 Sampled Iron Manaanese 11/12/2013 Sampled Iron Manaanese 4122/2014 Sampled Iron Manaanese 811912014 Sampled Iron Manaanese 11/11/2014 Sampled Iron Manaanese Conducted for antimony, MW-7 4124/2015 Sampled Iron Manaanese arsenic, beryllium, cadmium, 11/912015 Sampled Iron Manaanese Iron, lead, manganese. and 4112/2016 Sampled Iron Manaanese thallium. 11116/2016 Same led Iron Manaanese 4117/2017 Samcled Iron Manaanese Antimony, Arsenic, Beryllium, 11/14/2017 Sampled Cadmium, Iron, Lead, Manganese, Thallium 411/2013 Same led Iron, Manganese 8/1/2013 Same led Manganese 11/12/2013 Same led Iron Manganese 4122/2014 Same led Manaanese 8119/2014 Sampled Iron Manaanese 11/1112014 Sampled Manaanese Conducted for Iron and MW-9 4/24/2015 Sampled Manaanese manganese. 11110/2015 Sampled Iron Manaanese 4/12/2016 Sampled Iron Manaanese 11/16/2016 Sampled Iron Manaanese 4/1712017 Sampled Iron Manaanese 81112017 Sampled (1,4-Dioxane Onlvl None 11/14/2017 Sampled Iron Manaanese 4/112013 Sampled Iron, Manganese 8/1/2013 Sampled Iron Manaanese 11/12/2013 Sampled Iron Manaanese 4122/2014 Sampled Iron Manaanese 8119/2014 Samoled Iron Manaanese 11/11/2014 Samoled Iron Manaanese Conducted for benzene, iron, MW-10 4/2112015 Samcled Iron Manganese and manganese. 11/10/2015 Samcled Iron Manaanesa 4/12/2016 Sampled Iron Manganese 11/16/2016 Sampled Benzene Iron Manganese 4117/2017 Sampled Iron Manaanese 811/2017 Sampled (1 .4-Dioxane Only) None 11/15/2017 Sampled Iron Manaanese 4/1/201 3 Sampled Iron 8/112013 Sampled Iron 11/12/2013 Sampled Iron 4/22/2014 Sampled Iron Manganese 8119/2014 Sampled Iron Manaanese 11/1112014 Sampled Iron Manganese Conducted for arsenic, iron, and MW-11 4/2112015 Samoled Iron Manganese manganese. 11110/2015 Sampled Arsenic Iron Manganese 4/12/2016 Samcled Iron Manaanese 11/17/2016 Samclad Arsenic Iron 4/1812017 Samcled Iron Manaanese 8/112017 Samoled (1,4-Dloxane Onlv) None 11/15/2017 Sampled Iron Manaanese Page 3 of 5 Table 6. Summary of 2013. 2017 Data Availability, USEPA MCL Exceedances, and Statistical Analyses Performed Well ID Date Data Availability USEPA MCL Exceedances Statistical Analysis 4/1/2013 Sampled None 8/1/2013 Samoled Iron Manaanese 11/12/2013 Samoled None 4/22/20 14 Samoled None 8/20/2014 Samoled None None 11/11/2014 Samoled Conducted for Iron and MW- 12S 4/21/2015 Samoled None manganese. 11/11/2015 Samoled None 4/13/2016 Samoled None 11/17/2016 Samoled Iron Manl"lanese 4/18/2017 Samoled None 812/2017 Samoled 11,4-0ioxane OnM None 11115/2017 Samoled Iron 411/2013 Samoled Iron Man11anese 8/1/2013 Samoled Manaanese 11112/2013 Samoled Manaanese 4/22/2014 Samoled Iron Manaanese 8/20/2014 Samoled Iron Manaanese 11112/2014 Samoled Iran Manaanese Conducted for iron and MW-13 4/22/2015 Samoled Iron Mannanese manganese. 11/11/2015 Samoled Iron Manoanese 4/13/2016 Samoled Iron Manoanese 11/17/2016 Samoled Iron Manaanese 4119/2017 Samoled Iron Manaanese 812/2017 Same led /1,4-0ioxane Onlvl None 11/16/2017 Samnled Iron Manoanese WESTERN LANDFILL AREA 4/1/2013 Samoled Iron, Manaanese 8/1/2013 NS NA 11/12/2013 Samoled Iron Mannanase 4/22/2014 Samoled Iron Manaanese 8/19/2014 NS NA 11/12/2014 Samoled Iron Manaanese Conducted for Iron and B-5 4/23/2015 Samoled Iron Mannanesa manganese. 11/9/2015 Samoled Iron Manaanese 4/12/2016 Samoled Iron Manaanase 11/17/2016 Samoled Iron Manaanese 4/17/2017 Samoled Iron Mannanese 11/14/2017 Samoled Iron Mannanese Iron, Manganese, Methylene 4/1/2013 Sampled Chloride 8/1/2013 Samoled Iron Manaanese 11/12/2013 Samoled Iron Mannanese 4/22/2014 Samoled Iron Mannanese 8/19/2014 Sampled Chromium {total), Iron, Manganese Conducted for chromium (lotal), BH-2 11112/2014 Samoled Iron Mannanese Iron, manganese, and methy1ene chloride. 4/23/2015 Sampled Chromium {total), Iron, Manganese 11/9/2015 SamDled Iron Manaanese 4/12/2016 Samoled Iron Manaanese 11/16/2016 Samoled Iron Mannanese 4117/2017 Samoled Iron Mannanese 11/ 14/201 7 Samnled Iron Mannanese 4/1/2013 Samoled None 8/1/2013 NS NA 11/12/2013 Samoled None 4/22/201 4 Samoled None 8/19/2014 NS NA Conducted for Iron. Included In 11/13/2014 Samcled None MP-2A the statisUcal analysis as the 4/24/2015 Samoled None upgradlenl, bacltground well. 11112/2015 Samoled None 4/12/2016 Samoled Iron 11/18/2016 Samoled None 4/20/2017 Samcled None 11/17/2017 Sam•led None 4/ 1/2013 Samoled Iron Manaanese 8/1/2013 NS NA 11/12/2013 Samcled Iron Manaanese 4/22/2014 Samcled Iron Manaanesa 8/19/2014 NS NA Conducted for iron and 11/11/2014 Samoled Iron Mannanese manganese. Included In the MP-9 4/22/2015 Samoled Iron statistical analysis as the 11/10/2015 Samoled Iron Mannanese upgradlenl, bacltgroond well. 4112/2016 Samoled Iron Mannanese 11/16/2016 Samnted Iron Manaanese 4/1812017 Same led Iron Manaanese 11/15/2017 Sam,led Iron Manaanese Page 4 of 5 Table 6 • Summary of 2013 - 2017 Data Availability, USEPA MCL Exceedances, and Statistical Analyses Performed Well ID Date Data Availability USEPA MCL Exceedances Statlstlcal Analysis 4/1/2013 Sampled Iron Manaanese 8/1/2013 NS NA 11/12/2013 Sampled Iron Manaanese 4/2212014 Sampled Iron Manaanese 8/19/2014 NS NA 11/1212014 Sampled Iron Manaanese Conducted for Iron and MW-4C 4/23/2015 Sampled Iron Manaanese manganese. 11/10/2015 Sampled Iron Manaanese 4/13/2016 Samoled Iron Manganese 11/17/2016 Sampled Iron Manganese 4/17/2017 Samoled Iron Manoanese 11/14/2017 Samoled Iron Manoanese 4/1/2013 NS NA 8/1/2013 NS NA 11/12/2013 NS NA Not conducted for iron or 4/22/2014 Samoled Iron Manoanese MW-17D manganese due to insufficient 8/19/2014 NS NA sample size. 111 11/2014 Sampled Iron Manaanese 4/22/2015 Sampled (Metals Onlvl Iron Manaanese 11/11/2015 NS NA 4/1/2013 Sampled Iron, Manganese 8/1/2013 NS NA 11/1212013 Sampled Iron Manaanese 4/2212014 Sampled Iron Manaanese 8/1912014 NS NA MW-180 11/11/2014 Sampled Iron Manganese Conducted for iron and 4/2212015 Sampled Metals On~ Iron Manaanese manganese. 11/10/2015 Sampled Metals On~ Iron Manaanese 4/12/2016 Sampled Metals On~ Iron Manaanese 11/16/2016 Sampled Melals OnN Iron Manaanese 4/18/2017 Sampled Metals OnN Iron Manaanesa 11/16/2017 Samoled Metals OnN Iron Manaanese Notos: ~ ARCADIS,=.«::- NS = not sampled; NA= not applicable Page 5of 5 CITY: MANCHESTEq. CT Orv/GROUP: ENVCAD 08: B. SMALL PM. TM: G:\ENVCA0\1~1eMC1'HT212002'i0015\000041HTI170020015.1'..0 1,dwg LAYOUT; 1 SAVED; 3.16/2016 10:03 AM 0 ::u0 )> () 0 ~ ~0N 111 ~ Cf> o_ () )> r fT1 II..,. 0 0 o_ ~ )> ;a CJ) Z:r; =i ► er Cz ► g m GL;c ► m;u r ----i;um CJ 0 C(/)r ("') ():;: "C (/)- ;,;:o ► > oc::U - :::! Oz;,;: :;il!"gl 0 z~s;Z_z mz0 b .. z ()::U"Tl ::!or= ~[ s: O ► r ! >-a ~o -Jo, "' l LEGEND: _.qf - - - - BOUNDARY OF PROPERTIES OWNED BY LAUREL :~ ;~ PARK COALITION AND LAUREL PARK INC. __,:J; // . PARCEL BOUNDARY ,.11·' LANDFILL CAP AREA --x-- LANDFILL BOUNDARY FENCE , I , I /!'" --o-- CHAIN LINK FENCE \ I~ '. j LIMIT OF VEGETATIVE COVER ------LEACHATE COLLECTION SYSTEM ~', ' A., EDGE OF STREAM , ' -- ·--- , ' , -- --- ACCESS ROAD ~ ~ , / ' RIP RAP CHANNEL/EROSION CONTROL \,! " / /' it. LANDFILL MONITORING WELL Ia '" § ' @ BEDROCK MONITORING WELL a' \ \ OVERBURDEN MONITORING WELL I r· .. , .... • ♦ ~ I I!] EXTRACTION WELL ~ I \ >-t- MW 11 g~ I h~i.l @ Q. I , ~ "---EW-11 I \ " \~J~,~,~-EW-10 w~ fil I \ \~, \ I \ , "'ct' I ' EW-9 ' I % \ . MW-10 0 . \ \ ·, @ ~ '" I / . , / "' I d ~ -- ✓' \ \ ~EW-8 , " // ,, ;;"' -✓✓ MW-17S _.... _,,. ... \ <"~ - ..kEW-7 it' \ : I ·1-- \ ~ \~ ----;,, ~ :@MW--4C I \7ew ~ I it. / I MW-2 t,~EW-5 ! I ; "' it. t\_ , / :t ~ I\ \l ' MW-1 I 'j!J i~ I ''EW-4 I "a \\\ '-,, BH-8 ·) li1~ I s-ss+@B-5 '-.., '-',,_ ~~ \ ' \ i!"' \ ~ \ ' I f ~ a'.h_, I MW-18 \ : {J) EW-2 6 \ o' f MW-1~ \ \ \ \\ \ }-I ""'Q. g -- ~ - ' _, J. / ~8 I 600' "'§co~ j en ~ ~- ---/ GRAPHIC SCALE 0~ CONCRETE DECON PAD 5~ I _,,__,------\ tij ___ LAUREL PARK LANDFILL ~~ COMPRESSOR/ ~ §l :J; HUNTERS MOUNTAIN ROAD g~ ~ I - EQUIPMENT BUILDING NAUGATUCK. CONNECTICUT ~~ a ------~ ------2:n ~ O.o_~ t, \ :! ~ ~ .. l'! SITE PLAN i ~ofil~ gl'IJ -~ I- FIGURE o. .1gn & r,m 11.,,cy iltw w for natural and 13 ~ ~ ARCADIS buRtassets 2 LEGEND: LIMIT OF PROPERTIES COVERED BY INSTITUTIONAL CONTROL PLAN PARCEL LINES TAX LOT: I/6W59 SITE PERIMETER FENCE OWNER: LAUREL PARK INC. ACRES: 0.77 SECONDARY FENCE TAX LOT: H/6W9.5A OWNER: CAGNO LIMIT OF VEGETATIVE COVER ACRES: 7.59 RICHARD W. JOHNSON AND SKINNER ACCESS ROAD LEACHATE COLLECTION SYSTEM TAX LOT: H/6W13 SECOND PIECE OWNER: LAUREL PARK INC. LANDFILL CAP AREA ACRES: 4.60 PERIMETER DITCH DANIEL J. MH-10 MH-T01 MCDONNELL LANDFILL MONITORING WELL MH-T02 WALTER T. FLAHERTY JR. TAX LOT: H/6W13 FIRST PIECE MONITORING WELL HUNTERS MOUTAIN ROAD MW-13 OWNER: LAUREL PARK INC. ACRES: 3.15 EXTRACTION WELL MW-14 MH-T03 WETLANDS AREA MH-11 LAYOUT: LAYOUT: ----3 PLOTSTYLETABLE: ACADVER: 2:43 PM 8/14/2018 (LMS TECH)20.1S PAGESETUP: ---- SAVED: OW-3 MW-14S TAX LOT: H/6W40 MANHOLE MW-15S MW-12S OWNER: LAUREL PARK INC. MW-15D ACRES: 8.00 GROUNDWATER EXTRACTION SYSTEM PW-1 OW-4 MH-5A MH-05 MH-T04 DISCHARGE LINE EW-15 PW-1S EW-16 OW-5 OW-2 EW-17 MH-12 EW-20 EW-13 MH-T05 EW-18 EW-14 EW-12 EW-21 OW-1 TAX LOT: H/6W14 MW-16S EW-19 MH-04 EW-11 MW-11 MW-16D MH-01 MW-3 OWNER: LAUREL PARK INC. EW-10 BH-7 ACRES: 20.00 TAX LOT: I/6W54 OWNER: LAUREL PARK INC. ACRES: 14.90 EW-9 MW-17D MW-10 TAX LOT: H/6W35 MW-17S TAX LOT: H/6W34 FIRST PIECE OWNER: LAUREL PARK INC. EW-8 TAX LOT: H/6W9.5B MH-1B OWNER: LAUREL PARK INC. ACRES: TO BE DETERMINED MH-1A OWNER: LAUREL ACRES: 2.00 MH-3B EW-7 MW-4C PARK COALITION EW-6 MW-2 (FORMER CAGNO EW-5 PROPERTY) MH-1C MW-9 MW-1 ACRES: 25.47 MH-1D EW-4 B-5S B-5 TAX LOT: H/6W34 SECOND PIECE OWNER: LAUREL PARK INC. MH-3A ACRES: 2.80 BH-8 TAX LOT: I/6W37 EW-3 TAX LOT: I/6W31 MW-18S OWNER: LAUREL PARK INC. OWNER: LAUREL PARK INC. MW-18D ACRES: 10 MH-02 EW-2 ACRES: 12.55 MH-03 BH-2 MH-1F MH-1E MW-7 0 375' 750' 0 200' 400' EW-1 TAX LOT: I/6W16 MP-2B MP-9 EQUIPMENT OWNER: KENNETH MUYS GRAPHIC SCALE GRAPHIC SCALE MP-2A BUILDING ACRES: 0.95 LAUREL PARK LANDFILL HUNTERS MOUNTAIN ROAD FRANK PERROTTI TAX LOT: I/6W49.5 OWNER: LAUREL PARK NAUGATUCK, CONNECTICUT STATE OWNED HUNTERS MOUNTAIN ROAD COALITION (FORMER PERROTTI PROPERTY) ACRES: 7.06 LAUREL PARK INSTITUTIONAL TAX LOT: I/6W55 CONTROL PLAN FRANK PERROTTI OWNER: LAUREL PARK INC. HUNTERS MOUNTAIN ACRES: 1.84 ROAD FIGURE C:\Users\PPHalliw\OneDrive - ARCADIS\BIM 360 Docs\LAUREL PARK COALITION, LLC\Laurel Park 2018 Site Management and OM\2018\HT212002.0018\01-DWG\GWM-ELUR 2018.dwg OM\2018\HT212002.0018\01-DWG\GWM-ELUR and Park 2018 Site Management LLC\Laurel PARK COALITION, 360 Docs\LAUREL - ARCADIS\BIM C:\Users\PPHalliw\OneDrive CITY: MANCHESTER, CT DIV/GROUP: ENVCAD DB: B. SMALL PM: R. DIRENZO TM: M. ROMANOFF DIRENZO TM: SMALL PM: R. DB: B. DIV/GROUP: ENVCAD CT CITY: MANCHESTER, PLOTTED: PLOTTED: TRISH HALLIWELL, BY: 2:43 PM 8/14/2018 3 LEGEND: 670 BOUNDARY OF PROPERTIES OWNED BY LAUREL PARK COALITION AND LAUREL PARK INC. MW-13 PARCEL BOUNDARY (677.86) LANDFILL CAP AREA (669.27) MW-14 STONE WALL MW-14S LANDFILL BOUNDARY FENCE MW-12S CHAIN LINK FENCE MW-15S EW-15 (685.16) 670 (686.89) (695.44) EW-14 LIMIT OF VEGETATIVE COVER MW-15D OW-4 EW-16 (NM) (679.67) (681.06)OW-3 LEACHATE COLLECTION SYSTEM PW-1S PW-1 680 (681.77) OW-5 EW-12 EDGE OF STREAM (682.04)OW-2 (696.96) (685.24) EW-17 (694.60) ACCESS ROAD EW-13 EW-18 (686.52) MW-11 EW-21 (660.13) (680.03) (658.45) EW-11 RIP RAP CHANNEL/EROSION CONTROL EW-19(654.24) 680 MW-16S (693.78)MW-3 (687.09) OW-1 LANDFILL MONITORING WELL MW-16D (682.81) (693.88)BH-7 EW-10 BEDROCK MONITORING WELL EW-20 (683.97) (657.50) 690 OVERBURDEN MONITORING WELL LAYOUT: 4 SAVED: 8/14/2018 2:31 PM ACADVER: 20.1S (LMS TECH) PAGESETUP: ---- PLOTSTYLETABLE: PLOTSTYLETABLE: ACADVER: 2:31 PM 8/14/2018 (LMS TECH)20.1S PAGESETUP: ---- SAVED: LAYOUT: ---- 4 (696.22) EW-9 (694.12) EXTRACTION WELL 690 MW-10 NON-OPERATIONAL EXTRACTION WELL EW-8(691.53) 690 GROUNDWATER CONTOUR (DASHED WHERE INFERRED) 700MW-17D EW-7 (699.91) MW-17S (688.08) GROUNDWATER ELEVATION IN FEET ABOVE MEAN 700 SEA LEVEL EW-6 MW-4C (703.99) MW-9 (703.04) (DRY) ELEVATION GIVEN IS THE BOTTOM OF THE WELL (715.66) EW-5 (696.35) MW-2 GROUNDWATER FLOW DIRECTION (DRY) HATCHED CONTOURS REPRESENT GROUNDWATER MW-1 DEPRESSIONS (INWARD FLOW) (DRY) EW-4 (706.98) 710 BH-8 NOTES: B-5S (720.76) B-5 (704.42) 720 1. WELLS MW-4C, MW-3, AND MP-2A ARE SCREENED IN THE OVERBURDEN OR OVERBURDEN AND BEDROCK AND ARE NOT EW-3 (711.14) SOLEY REPRESENTATIVE OF CONDITIONS IN THE BEDROCK. 2. THIS FIGURE SHOULD NOT BE USED FOR CONSTRUCTION OR EW-2 LAND CONVEYANCE PURPOSES. MW-18S (712.50) MW-18D 0 200' 400' 710 BH-2 730 (724.07) GRAPHIC SCALE MW-7 (730.91) LAUREL PARK LANDFILL EW-1 HUNTERS MOUNTAIN ROAD (710.65) NAUGATUCK, CONNECTICUT (719.93) MP-9 CONCRETE DECON PAD BEDROCK GROUNDWATER CONTOUR MP-2B (726.97) 730 MAP - APRIL 12, 2018 MP-2A (GES PUMPS ON) COMPRESSOR/ 720 EQUIPMENT BUILDING FIGURE C:\Users\PPHalliw\OneDrive - ARCADIS\BIM 360 Docs\LAUREL PARK COALITION, LLC\Laurel Park 2018 Site Management and OM\2018\HT212002.0018\01-DWG\GWM-April2018.dwg and Park 2018 Site Management LLC\Laurel PARK COALITION, 360 Docs\LAUREL - ARCADIS\BIM C:\Users\PPHalliw\OneDrive CITY: MANCHESTER, CT DIV/GROUP: ENVCAD DB: B. SMALL PM: R. DIRENZO TM: M. ROMANOFF DIRENZO TM: SMALL PM: R. DB: B. DIV/GROUP: ENVCAD CT CITY: MANCHESTER, PLOTTED: PLOTTED: TRISH HALLIWELL, BY: 2:31 PM 8/14/2018 4 LEGEND: 670 BOUNDARY OF PROPERTIES OWNED BY LAUREL PARK COALITION AND LAUREL PARK INC. MW-13 PARCEL BOUNDARY (677.39) LANDFILL CAP AREA MW-14(667.99) STONE WALL MW-14S 670 LANDFILL BOUNDARY FENCE MW-12S CHAIN LINK FENCE MW-15S EW-15 (683.54) (700.60) (694.70) (701.63) LIMIT OF VEGETATIVE COVER EW-16 EW-14 MW-15D OW-4 (686.24) 680 (681.30)OW-3 LEACHATE COLLECTION SYSTEM PW-1S PW-1 (681.79) OW-5 EW-12 EDGE OF STREAM (683.08)OW-2 (697.85) (685.41) EW-17 (690.79) ACCESS ROAD EW-13 EW-21 EW-18 (686.41) MW-11 (690.60) (681.66) (678.35) RIP RAP CHANNEL/EROSION CONTROL EW-19(684.28) EW-11 MW-16S690 (693.54)MW-3 (687.19) 680 OW-1 LANDFILL MONITORING WELL MW-16D (686.61) (693.80)BH-7 EW-10 BEDROCK MONITORING WELL EW-20 (688.81) (688.13) 690 OVERBURDEN MONITORING WELL LAYOUT: 5 SAVED: 8/14/2018 2:32 PM ACADVER: 20.1S (LMS TECH) PAGESETUP: ---- PLOTSTYLETABLE: ---- SAVED: LAYOUT: ----5 PLOTSTYLETABLE: ACADVER: 2:32 PM 8/14/2018 (LMS TECH)20.1S PAGESETUP: (696.22) EW-9 (696.09) EXTRACTION WELL MW-10 NON-OPERATIONAL EXTRACTION WELL EW-8 700 (698.25) 690 GROUNDWATER CONTOUR (DASHED WHERE INFERRED) MW-17D EW-7 (698.44) MW-17S (696.53) GROUNDWATER ELEVATION IN FEET ABOVE MEAN SEA LEVEL EW-6 MW-4C (703.81) 700MW-9 (701.80) (DRY) ELEVATION GIVEN IS THE BOTTOM OF THE WELL (713.68) EW-5 (704.98) MW-2 GROUNDWATER FLOW DIRECTION (DRY) 710 HATCHED CONTOURS REPRESENT GROUNDWATER MW-1 DEPRESSIONS (INWARD FLOW) (DRY) EW-4 (718.60) BH-8 720 NOTES: B-5S (720.73) B-5 (704.21) 1. WELLS MW-4C, MW-3, AND MP-2A ARE SCREENED IN THE OVERBURDEN OR OVERBURDEN AND BEDROCK AND ARE NOT EW-3 (723.41) SOLEY REPRESENTATIVE OF CONDITIONS IN THE BEDROCK. 2. THIS FIGURE SHOULD NOT BE USED FOR CONSTRUCTION OR EW-2 LAND CONVEYANCE PURPOSES. 710 MW-18S (724.23) MW-18D 0 200' 400' 730 BH-2 (724.17) GRAPHIC SCALE MW-7 (730.41) LAUREL PARK LANDFILL EW-1 HUNTERS MOUNTAIN ROAD (730.97) NAUGATUCK, CONNECTICUT 730 (719.90) MP-9 CONCRETE DECON PAD BEDROCK GROUNDWATER CONTOUR MP-2B (727.12) MAP - MAY 1, 2018 MP-2A (GES PUMPS OFF) COMPRESSOR/ 720 EQUIPMENT BUILDING FIGURE C:\Users\PPHalliw\OneDrive - ARCADIS\BIM 360 Docs\LAUREL PARK COALITION, LLC\Laurel Park 2018 Site Management and OM\2018\HT212002.0018\01-DWG\GWM-May2018.dwg and Park 2018 Site Management LLC\Laurel PARK COALITION, 360 Docs\LAUREL - ARCADIS\BIM C:\Users\PPHalliw\OneDrive CITY: MANCHESTER, CT DIV/GROUP: ENVCAD DB: B. SMALL PM: R. DIRENZO TM: M. ROMANOFF DIRENZO TM: SMALL PM: R. DB: B. DIV/GROUP: ENVCAD CT CITY: MANCHESTER, PLOTTED: PLOTTED: TRISH HALLIWELL, BY: 2:32 PM 8/14/2018 5 Notes: 1. Chemicals are depicted if at least one exceedance of a standard or criterion occurred. Exceedances of proposed standards or secondary MCLs (odor and esthetics) are not included. 1,2-DCA = 1,2-Dichloroethane. MW-14S MP-11AU 2. Exceedances are based on the maximum concentration Date 2009 2010 2011 2012 detected during any sampling event in each year. Zinc * **Text 3. All wells were sampled except MW-1 and MW-2. DD 4. This site plan was developed from the 2011 Annual MW-15D D Monitoring Report, Figure 3 by Arcadis, dated May 15, D D Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 D 2012. Benzene Text MW-14 D D 1,2-DCA * U D 5. Locations of site features depicted hereon are 1,4-Dioxane na na na na A!D U D approximate and given for illustrative purposes only. Chromium(Total) * **** MW-13 D D D Legend D D U D D D 0# Landfill Well MW-15S A!A! OW-3 MW-12S U D D OW-4U OW-5 EW-15 U Bedrock Monitoring Well U D PW-1D EW-16 EW-14 EW-13 MW-11 D PW-1S A!U EW-17 A! Overburden Monitoring Well D EW-12 MW-17D EW-18 U D OW-2U EW-11 Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 D Extraction Well EW-20 EW-19 MW-3 D Arsenic * ** U EW-21 U Text D U BH-7 D Chromium(Total) * ** MW-16SA! OW-1 EW-10 Monitoring Wells Sampled in 2017 D D MW-17S MW-16DDA! D Point of Compliance Well Date 2009 2010 2011 2012 Text D EW-9 Arsenic ** D Access Road D MW-10 D U D DD D Fence EW-8 D AA! D !D Property Line D D EW-7 D D EW-6 Leachate Collection System U MW-4C MW-9 D D MW-20# U Equipment & Storage Building EW-5 D D MW-10# D D CT RSR Exceedances B-5 EW-4 A! D U D BH-8 U > GA Groundwater Protection Criteria D D D > Surface Water Protection Criteria EW-3 D > Residential Volatization Criteria D B-5S Text MW-18S A! D Date 2009 2010 2011 2012 D Federal Drinking Water Standard Exceedances EW-2 A! Arsenic D USEPA Maximum Contaminant Level D D D Zinc ** * D D EW-1 D D D BH-2 UD D D D CT DPH Exceedances MW-18D MW-7D D D D D D > CT DPH Action Level (3 ug/L) D D Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 UD D D Text D Arsenic * *** D D D U * Detected, but below standard MP-2BU MP-9 MP-2AU (blank) not detected/below detection limit na not applicable 0 150 300 600 1 inch = 303 feet Feet FIGURE 6 OVERBURDEN GROUNDWATER RESULTS Engineering a Sustainable Future LAUREL PARK LANDFILL Nobis Engineering, Inc. 585 Middlesex Street HUNTERS MOUNTAIN ROAD Lowell, MA 01851 NAUGATUCK, CONNECTICUT (978) 683-0891 www.nobiseng.com PREPARED BY: JH CHECKED BY: LC Client-Focused, Employee-Owned R:\80000 Task Orders\80007Laurel Park\Technical Data\GIS\Figures\Figure 21 Laurel Park GW 2017.mxd 5/30/2018 08:22 jharrington ³ PROJECT NO. 80007 DATE: MAY 2018 MW-13 Notes: MW-14 Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 ThalliumText 1. Chemicals are depicted if at least one exceedance of a Zinc * * ******Text standard or criterion occurred. Exceedances of proposed OW-5 1,4-Dioxane na na na na standards or secondary MCLs (odor and esthetics) are not Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 included. 1,2-DCA = 1,2-Dichloroethane. Benzene MP-11A U OW-4 Methylene Chloride 2. Exceedances are based on the maximum concentration detected during any sampling event in each year. Date 2009 2010 2011 2012 2013 2014 2015 2016Text 2017 Arsenic Text * ** Thallium Chromium(Total) * *** 3. All wells were sampled except MW-1 and MW-2. Thalluim OW-3 DD MW-12S 4. This site plan was developed from the 2011 Annual D Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 Monitoring Report, Figure 3 by Arcadis, dated May 15, D D Text D 2012. Chromium(Trivalent) na na na na na na na D Chromium (Total) * ****** Chromium(Total) * ** * D Nickel * ******** U D 5. Locations of site features depicted hereon are MW-14S Zinc * ******** A!D U D approximate and given for illustrative purposes only. PW-1 D MW-11 D Text Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 D Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 Legend Benzene D D Arsenic *** 1,2-DCA * Text U D Thallium D D 0# Landfill Well Acetone * * MW-15S A!A! MW-12S 1,4-Dioxane na na na na U D Chromium(Total) ** *** D MW-15D EW-15 MW-3 U U Bedrock Monitoring Well 1,4-Dioxane na na na na U EW-14 D Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 D EW-16 Text EW-13 D Benzene PW-1SA!U EW-17 EW-12 A! Overburden Monitoring Well D EW-18 Arsenic OW-2 EW-11 U D U Chromium(Total) **** Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 D EW-19 Extraction Well EW-20 U D Selenium * *** ** Benzene EW-21 D U U D 1,4-Dioxane na na na na Arsenic * Monitoring Wells Sampled in 2017 MW-16SA! EW-10 Cadmium Text D D BH-7 1,4-Dioxane na na na na A! D Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 D MW-16D Text Point of Compliance Well Benzene EW-9 D OW-1 Chlorobenzene * * DD Access Road Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 D Isopropylbenzene ***** * D Benzene U DD D 1,2-DCA * Fence Chlorobenzene *** A! D EW-8 D Methylene Chloride * A! 1,2-DCA Text D MW-17D Chromium(Total) * *** Property Line D Methylene Chloride D MW-17S EW-7 Lead ***** * Vinyl Chloride * ** D Arsenic D EW-6 Leachate Collection System Arsenic U MW-4C Selenium ****** * D Chromium(Total) * *** ** D EW-5 1,4-Dioxane na na na na MW-20# U Equipment & Storage Building Selenium **** ** D D MW-10 1,4-Dioxane na na na na MW-10# D Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 D CT RSR Exceedances B-5S EW-4 Benzene A! D U D U Thallium > GA Groundwater Protection Criteria D Text D 1,4-Dioxane na na na na D > Surface Water Protection Criteria B-5 MW-9 D EW-3 > Residential Volatization Criteria Date 2009 2010 2011 2012 2013 2014 2015 2016Text 2017 D Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 1,2-DCA ** * * MW-18SA! D D ChromiumText (Total) * ****** Federal Drinking Water Standard Exceedances EW-2 MW-18DA! Nickel * * ****** D USEPA Maximum Contaminant Level D D D Zinc * ******** D EW-1 D D D D UD D D D CT DPH Exceedances BH-2 D BH-8 D D D Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 D D > CT DPH Action Level (3 ug/L) D D Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 UD D D Benzene *** D BenzeneText D D Methylene Chloride D U MP-2B 1,2-DCA * Detected, but below standard 1,2-DCA *** * Text U MP-2A Arsenic (blank) not detected/below detection limit Chromium(Total) * ** ** U MW-7 Chromium(Total) * **** Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 na not applicable Cadmium MP-9 Antimony 1,4-Dioxane na na na na 0 150 300 600 Date 2009 2010 2011 2012 2013 2014 2015 2016 2017 Arsenic Text Benzene *** Text* Beryllium Cadmium * Cadmium 1 inch = 303 feet Feet Chromium (Total) *** ** Copper * FIGURE 7 Silver * Thallium BEDROCK GROUNDWATER RESULTS Engineering a Sustainable Future LAUREL PARK LANDFILL Nobis Engineering, Inc. 585 Middlesex Street HUNTERS MOUNTAIN ROAD Lowell, MA 01851 NAUGATUCK, CONNECTICUT (978) 683-0891 www.nobiseng.com PREPARED BY: JH CHECKED BY: LC Client-Focused, Employee-Owned R:\80000 Task Orders\80007Laurel Park\Technical Data\GIS\Figures\Figure 21 Laurel Park GW 2017.mxd 5/30/2018 08:24 jharrington ³ PROJECT NO. 80007 DATE: MAY 2018