/r" /"" / 'V/J / /?, .' 1.1 ,v- < (. / f ( GEI Consultants, Inc. ATLANTIC ENVIRONMENTAL DIVISION REMEDIAL INVESTIGATION FORMER UGI MANUFACTURED GAS PLANT COLUMBIA, PENNSYLVANIA VOLUME I: TEXT SDMS DocID 2074507 Submitted to: Pennsylvania Power & Light Company Two North Ninth Street Allentown, PA 18101 and UGI Utilities P.O. Box 12677 100 Kachel Boulevard, Suite 400 Reading, PA 19612-2677 GEI Consultants, Inc. Atlantic Environmental Division 1021 Main Street 188 Norwich Avenue Winchester, MA 01890 Colchester, CT 06415 April 1998 (617)721-4000 (860)537-0751 Project No. 96437 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION IB 841 Chestnut Building Philadelphia, Pennsylvania 19107 Office of Superfund Direct Dial (215) 597-3166 Steven J. Donohue Mail Code (3HW22) Douglas C. Ammon, P.E. April 8, 1998 Project Manager Clean Sites Environmental Services, Inc. 635 Slaters Lane, Suite 130 Alexandria, VA 22314 Re: UGI Columbia Gas MGP Site Approval of Final Remedial Investigation Report Dear Doug: The United States Environmental Protection Agency ("EPA") has received and reviewed the April 1998 Remedial Investigation Report and Appendices ("RT) for the UGI Columbia Manufactured Gas Plant Site ("Site"). The RI was submitted by the Atlantic Environmental Division of GEI Consultants, Inc. ("Atlantic") and received by EPA on April 3, 1998. EPA has reviewed the RI to ensure revisions made to the text and appendices were responsive to comments made by EPA in a March 5, 1998 letter. EPA approves the RI and considers it final. As you know, the Pennsylvania Department of Environmental Protection ("PADEP") did not have any comments on revised pages of the RI which Atlantic submitted in correspondence dated December 22, 1997. I spoke with Tony Martinelli, the PADEP Project Manager for the Site, today and he confirmed that PADEP had no further comments on the RI and also considered it final. Please contact EPA and PADEP as soon as possible to schedule a meeting to discuss the Feasibility Study for the Site. If you have any questions on the above comments please contact me at the number above. Sincerely, Steven J. Donohue Remedial Project Manager cc: Anthony Martinelli, PADEP CONTENTS SECTION PAGE EXECUTIVE SUMMARY ES-1 1.0 INTRODUCTION 1-1 1.1 Purpose of Report 1-1 1.2 Report Organization 1-2 1.3 Site Background 1-2 1.3.1 Site Description 1-2 1.3.2 Site History 1-3 1.3.2.1 Past Industrial Activity 1-4 1.3.2.2 Petroleum Product Spills and Leaks; Filling Activities Near the Site . 1-5 1.3.3 Previous Investigations 1-7 2.0 STUDY AREA INVESTIGATIONS 2-1 2.1 Investigations 2-1 2.1.1 Site Surveying 2-1 2.1.2 Waste Generation and Disposal 2-2 2.1.3 Heavy Equipment Decontamination 2-3 2.2 Local Zoning Study 2-3 2.3 Surface-Soil Sampling 2-3 2.4 Surface Water and Sediment Sampling and Analysis 2-5 2.5 Existing Monitoring Well Survey 2-7 2.6 Geophysical Investigations 2-8 2.6.1 Conduit Location Survey 2-9 2.6.2 Surface Seismic Refraction Survey 2-9 2.6.3 Borehole Installation 2-10 2.6.4 Downhole Seismic Refraction Survey and Tomographic Imaging .... 2-11 2.6.5 Angle Corehole Installation 2-12 2.7 Soil Boring, Monitoring Well Installation, and Exploratory Trenching 2-13 2.7.1 Supplemental Soil Borings 2-14 CONTENTS (continued) SECTION PAGE 2.7.2 Boring and Coring Procedures 2-14 2.7.3 Subsurface-Soil Sampling 2-15 2.7.3.1 Ultraviolet Fluorescence Screening 2-17 2.7.4 Exploratory Trenching 2-17 2.7.5 Monitoring Well Installation 2-18 2.8 Groundwater Investigations 2-19 2.8.1 Groundwater Sampling and Analysis 2-20 2.8.1.1 Purging and Sampling Equipment 2-20 2.8.1.2 Groundwater Purging and Discharge Monitoring 2-21 2.8.1.3 Groundwater Sampling Procedures 2-23 2.8.2 Permeability Testing/Falling Head Slug Tests 2-24 2.8.3 Bedrock Hydraulic Conductivity Testing 2-24 2.8.3.1 Single Well Pump Testing 2-25 2.8.4 Local Groundwater Use Survey 2-26 2.8.4.1 Local Groundwater Discharge 2-28 2.9 Susquehanna River Bathymetry 2-28 2.10 Groundwater Flow Modeling (Hydraulic Gradients) 2-29 2.11 Baseline Human Health and Ecological Risk Assessments 2-29 3.0 PHYSICAL CHARACTERISTICS OF THE STUDY AREA 3-1 3.1 Climatology 3-1 3.2 Demography and Land Use in the Site Vicinity 3-2 3.2.1 Future Land Use 3-3 3.3 Local Zoning 3-3 3.4 Local Groundwater Use 3-4 3.5 Surface Water Hydrology 3-5 CONTENTS (continued) SECTION PAGE 3.5.1 Local Surface-Water Use 3-6 3.6 Regional Geology 3-7 3.6.1 Regional Physiography 3-7 3.6.2 Regional Bedrock Geology 3-8 3.7 Site-specific Geology 3-9 3.7.1 Surface Seismic Refraction Survey 3-10 3.7.2 Borehole Seismic Velocity Imaging 3-11 3.7.3 Angle Corehole Results 3-13 3.7.4 Fracture Permeability Testing 3-14 3.8 Regional Surficial Soils 3-14 3.9 Site-Specific Surficial Soils and Geology 3-14 3.10 Hydrogeology 3-17 3.10.1 Regional Hydrogeology 3-17 3.10.2 Site-specific Hydrogeology 3-18 3.10.3 Local Groundwater Discharge 3-21 3.11 Susquehanna River Bathymetry 3-21 4.0 NATURE AND EXTENT OF CONTAMINATION 4-1 4.1 Surface Soils 4-1 4.1.1 Volatile Organic Compounds 4-1 4.1.2 Semivolatile Organic Compounds 4-2 4.1.3 Inorganic Compounds 4-2 4.1.4 Summary of Surface-Soil Analyses 4-2 4.2 Shawnee Creek Surface Water and Sediment 4-3 4.2.1 Surface Water 4-4 4.2.2 Sediments 4-4 4.3 Subsurface Soils 4-5 CONTENTS (continued) SECTION PAGE 4.3.1 Upgradient Boring 4-5 4.3.2 On-Site Borings 4-6 4.3.3 Off-Site Borings, Exploratory Trenches Adjacent to Susquehanna River, and Garage Excavation Samples 4-8 4.3.4 Additional Off-Site Borings and Exploratory Trenches 4-10 4.3.5 Ultraviolet (Fluorescent) Screening 4-12 4.3.6 Summary of Subsurface-Soil Analyses 4-12 4.4 Groundwater 4-13 4.4.1 Upgradient Groundwater 4-13 4.4.2 On-Site Groundwater 4-14 4.4.3 Off-Site Groundwater 4-15 4.4.4 QA in Groundwater Samples 4-17 4.4.5 Summary of Groundwater Impacts 4-18 4.5 Private Well Groundwater Quality 4-18 4.6 Physical Extent of Contamination 4-19 4.6.1 Vertical Extent 4-19 4.6.2 Area! Extent by Elevation 4-20 4.6.3 Evaluation of Water Table and DNAPL Elevations 4-22 4.7 Impacted Soil Volume and Bedrock Tar Volume Estimates 4-23 4.7.1 Impacted Soils Volume Estimation 4-23 4.7.2 Bedrock Tar Volume Estimation 4-24 5.0 CONTAMINANT FATE AND TRANSPORT 5-1 5.1 Fate and Transport Characteristics 5-1 5.1.1 Factors Affecting Fate and Transport Processes 5-1 5.1.2 Characteristics of Identified Site Contaminants 5-4 5.1.2.1 Volatile Organic Compounds 5-4 5.1.2.2 Semivolatile Organic Compounds 5-6 5.1.2.3 Inorganic Compounds 5-11 - iv - CONTENTS (continued) SECTION PAGE 5.2 Sources, Pathways, and Receptors 5-12 5.2.1 Contaminant Sources 5-14 5.2.2 Pathways 5-15 5.2.3 Receptors 5-17 6.0 CONCLUSIONS AND RECOMMENDATIONS 6-1 6.1 General Conclusions 6-1 6.2 Specific Conclusions 6-2 6.2.1 Surface Water Hydrology 6-2 6.2.2 Geology 6-2 6.2.3 Hydrogeology 6-2 6.2.4 Nature and Extent of Contamination 6-3 6.3 Recommendations 6-4 7.0 REFERENCES 7-1 VOLUME II LIST OF FIGURES Figure ES-1: Summary of Findings Figure 1-1: Site Location Map Figure 1-2: Former MGP Site and Vicinity Figure 1-3: Historical Composite Map Gas Plant and Surrounding Structures 1894-1995 Figure 1-4: Previous Sampling Locations Figure 1-5: Tar Observations, Previous Borings and Probable Fracture Lineaments Figure 2-1: Sampling Locations 1994-1995 Figure 2-2: Locations of 1994-1995 Seismic Lines, Boreholes and Angle Coreholes Figure 2-3: Locations of Known Private Wells Figure 3-1: Land Use and Surface Water Flow Paths in Site Vicinity Figure 3-2: Surface Water Use in Site Vicinity Figure 3-3: Apparent Fracture Traces 1985 and 1994 Figure 3-4: Seismic Imaging Results for Test Locations S-1/S-2 Figure 3-5: Seismic Imaging Results for Test Locations S-3/S-4 Figure 3-6: Angle Corehole AC-01 Trajectory - v - CONTENTS (continued) Figure 3-7: Top of Bedrock Contours Figure 3-8: Geologic Sections Location Map Figure 3-9: Geologic Section A-A' Figure 3-10: Geologic Section B-B' Figure 3-11: Geologic Section C-C' Figure 3-12: Overburden Water Table Contours: March 23 and August 21, 1995 Figure 3-13: Shallow Bedrock Water Table Contours: March 23 and August 21, 1995 Figure 3-14: Deep Bedrock Water Table Contours: March 23 and August 21, 1995 Figure 3-15: Susquehanna River Depths Near the Study Area Figure 4-1: Total MAN and PAH Concentrations: Surface Soils, Sediment, and Water (ppm) Figure 4-2: Total MAH and PAH Concentrations: Subsurface Soils (ppm) Figure 4-3: Total MAH and PAH Concentrations: Groundwater (ppm) Figure 4-4: Physical Evidence of Contamination Geologic Section A-A' Figure 4-5: Physical Evidence of Contamination Geologic Section B-B' Figure 4-6: Physical Evidence of Contamination Geologic Section C-C' Figure 4-7: Interpreted Areal Impacts at Elevations 250-245 Figure 4-8: Interpreted Areal Impacts at Elevations 245-240 Figure 4-9: Interpreted Areal Impacts at Elevations 240-235 Figure 4-10: Interpreted Areal Impacts at Elevations 235-230 Figure 4-11: Interpreted Areal Impacts at Elevations 230-225 Figure 4-12: Interpreted Areal Impacts at Elevations 225-220 Figure 4-13: Interpreted Areal Impacts at Elevations 220-210 Figure 4-14: Interpreted Areal Impacts at Elevations 210-200 Figure 4-15: Interpreted Areal Impacts at Elevations 200-180 Figure 4-16: Tar Observations, Previous & Rl Borings and Probable Fracture Lineaments Figure 4-17: Composite Areal Extent of Physical Overburden MGP Impacts VOLUME III LIST OF TABLES Table 1-1: Columbia MGP Site - Previous Investigations Analytical Results - Subsurface Soil (ppm) (TRC, 1986) Table 1-2: Columbia MGP Site - Previous Investigations Ep Extractable Metals - Subsurface Soil (ppm) (TRC,