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fi- R S .0 .& Document 10 of 20 _ u q if . COMPILATION OF HISTORICAL C-8 DATA DUPONT WASHINGTON WORKS MAIN PLANT AND LANDFILLS rCc"zozi t-O Date: January 2002 Project No: D6WW7423 -J 11!) CORPORATE REMEDIATION GROUP An Alliance botv/een DuPont and URS Diamond Barley Mill Plaza, Building 27 Wilmington, Delaware 19805 CON'iAIN NO CEM 000432 E ID 1 6 8 0 5 7 M A H 00042 9 TABLE OF CONTENTS 1.0 Introduction......................................................................................................................... 1-1 1.1 Document Organization......................................................................................... 1-1 1.2 C-8 Historical Laboratory Analysis......................................................................1-1 1.3 Physicochemical Data for Ammonium Perfluorooctanoate (C-8) .................. 1-2 1.4 References................................................................................................................. 1-3 2.0 Washington Works Main Plant........................................................................................2-1 2.1 Introduction...............................................................................................................2-2 2.2 Environmental Setting............................................................................................ 2-3 2.2.1 G eology...................................................................................................... 2-3 2.2.2 Hydrology, Hydrogeology and Groundwater Flow............................. 2-3 2.3 Water Quality............................................................................................................2-6 2.3.1 Surface Water Quality.............................................................................. 2-6 2.3.2 Groundwater Quality................................................................................ 2-6 2.3.3 Drinking/Tap Water Quality.................................................................... 2-7 2.4 Site Conceptual Model............................................................................................ 2-7 2.5 Data Gaps.................................................................................................................. 2-8 2.6 References................................................................................................................. 2-8 3.0 Local Landfill......................................................................................................................3-1 3.1 Introduction............................................................................................................... 3-2 3.2 Environmental Setting............................................................................................ 3-2 3.2.1 G eology...................................................................................................... 3-2 3.2.2 Hydrology, Hydrogeology and Groundwater Flow............................. 3-3 3.3 Water Quality............................................................................................................3-4 3.3.1 Surface Water Quality.............................................................................. 3-4 3.3.2 Groundwater Quality................................................................................ 3-4 3.4 Site Conceptual Model............................................................................................ 3-5 3.5 Data Gaps.................................................................................................................. 3-6 3.6 References.................................................................................................................3-6 4.0 Letart Landfill.................................................................................................................... 4-1 4.1 Introduction............................................................................................................... 4-2 4.2 Environmental Setting............................................................................................ 4-2 4.2.1 G eology...................................................................................................... 4-2 4.2.2 Hydrology, Hydrogeology and Groundwater Flow............................. 4-3 4.3 Water Quality........................................................................................... 4-4 4.3.1 Surface Water Quality.............................................................................. 4-4 4.3.2 Groundwater Quality..................................................................................4-5 4.4 Site Conceptual Model............................................................................................ 4-6 4.5 Data Gaps.................................................................................................................. 4-7 4.6 References................................................................................................................. 4-8 000433 EID168058 M A H 000430 Main Plant and Landfills Table of Contents 5.0 Dry Run Landfill.............................................................................................................. 5-1 5.1 Introduction..............................................................................................................5-2 5.2 Environmental Setting............................................................................................ 5-2 5.2.1 G eology......................................................................................................5-2 5.2.2 Hydrology, Hydrogeology and Groundwater Flow............................. 5-3 5.3 Water Quality........................................................................................................... 5-4 5.3.1 Surface Water Quality..............................................................................5-4 5.3.2 Groundwater Quality................................................................................5-4 5.4 Site Conceptual Model............................................................................................ 5-5 5.5 Data Gaps.............................. 5-6 5.6 References.................................................................................................................5-6 TABLES Table 2.0 Washington Works Main Plant Monitoring Wells Construction Data Table 2.1 A Washington Works Main Plant Analytical Data Table - Surface Water Table 2 .IB Washington Works Main Plant Analytical Data Table - Groundwater Table 2.1C Washington Works Main Plant Analytical Data Table - Drinking Water Table 3.0 Local Landfill Monitoring Wells Construction Data Table 3.1 A Local Landfill Analytical Data Tables - Surface Water Table 3 .IB Local Landfill Analytical Data Tables - Groundwater Table 4.0 Letart Landfill Monitoring Wells Construction Data Table 4.1 A Letart Landfill Analytical Data Tables - Surface Water Table 4 .IB Letart Landfill Analytical Data Tables - Groundwater Table 5.0 Dry Run Landfill Monitoring Wells Construction Data Table 5.1 A Dry Run Landfill Analytical Data Tables - Surface Water Table 5 .IB Dry Run Landfill Analytical Data Tables - Groundwater Figure 1.0 Figure 2.0 Figure 2.1 Figure 2.2 Figure 2.3 Figure 2.4A Figure 2.4B Figure 2.4C Figure 2.4D FIGURES Solubilities o f C7F15COOM in Water as a Function o f Temperature Washington Works Main Plant Location and SWMU Map Washington Works Main Plant and Local Landfill 1-mile Radius Map Washington Works Main Plant Monitoring Well and Surface Water Sample Location Map Washington Works Main Plant Cross Section Location Map Washington Works Main Plant Cross Section A-A' Washington Works Main Plant Cross Section B-B' Washington Works Main Plant Cross Section C-C' Washington Works Main Plant Cross Section D-D' Compilation of history data Draft 2.doc Jan. 1 1 .0 2 Wilmington. DE 000494 ____ _________ EID168059 M A H 000431 Main Plant and Landfills Table of Contents Figure 2.4E Washington Works Main Plant Cross Section E-E' Figure 2.4F Washington Works Main Plant Cross Section F-F' Figure 2.5A Washington Works Main Plant Groundwater Elevation Map - November 2000 Figure 2.5B Washington Works Main Plant Groundwater Elevation Map - February 1999 Figure 2.5C Washington Works Main Plant Groundwater Elevation Map - November 1998 Figure 2.6A Washington Works Main Plant C-8 Concentration Map - February 1999 Figure 2.6B Washington Works Main Plant C-8 Concentration Map - November 1998 Figure 3.0 Local Landfill Location Map Figure 3.1 Local Landfill and Washington Works Main Plant 1-mile Radius Map Figure 3.2 Local Landfill Monitoring Well and Surface Water Sample Location Map Figure 3.3 Local Landfill Cross Section Location Map Figure 3.4A Local Landfill Cross Section A -A ' Figure 3.4B Local Landfill Cross Section B-B' Figure 3.5A Local Landfill Groundwater Elevation Map - November 2001 Figure 3.5B Local Landfill Groundwater Elevation Map - December 2000 Figure 3.5C Local Landfill Groundwater Elevation Map - November 1999 Figure 3.5D Local Landfill Groundwater Elevation Map - November 1998 Figure 3.5E Local Landfill Groundwater Elevation Map - November 1997 Figure 3.5F Local Landfill Groundwater Elevation Map - December 1996 Figure 3.5G Local Landfill Groundwater Elevation Map - December 1994 Figure 3.6A Local Landfill C-8 Concentration - May 2001 Figure 3.6B Local Landfill C-8 Concentration - May 2000 Figure 3.6C Local Landfill C-8 Concentration - May 1999 Figure 3.6D Local Landfill C-8 Concentration - May 1998 Figure 4.0 Letart Landfill Location Map Figure 4.1 Letart Landfill 1-mile Radius Map Figure 4.2 Letart Landfill Monitoring Well and Surface Water Sample Location Map Figure 4.3 Letart Landfill Cross Section Location Map Figure 4.4A Letart Landfill Cross Section A-A' Figure 4.4B Letart Landfill Cross Section B-B' Compilation of history data Draft 2.doc Jan. 14, 02 Wilmington, DE Mi 000455 ______ E ID 1 6 8 0 6 0 M AH000432 Main Plant and Landfills Table of Contents Figure 4.5A Letart Landfill F-Zone Groundwater Elevation Map - November 2001 Figure 4.5B Letart Landfill F-Zone Groundwater Elevation Map - January 2001 Figure 4.5C Letart Landfill F-Zone Groundwater Elevation Map - October 1999 Figure 4.5D Letart Landfill F-Zone Groundwater Elevation Map - October 1998 Figure 4.5E Letart Landfill F-Zone Groundwater Elevation Map - December 1994 Figure 4.5F Letart Landfill F-Zone Groundwater Elevation Map - December 1992 Figure 4.6A Letart C-8 Concentration Map - July 2001 Figure 4.6B Letart C-8 Concentration Map - January 2000 Figure 4.6C Letart C-8 Concentration Map - July 1999 Figure 4.6D Letart C-8 Concentration Map - November 1991 Figure 5.0 Dry Run Landfill Location Map Figure 5.1 Dry Run Landfill 1-mile Radius Map Figure 5.2 Dry Run Landfill Monitoring Well and Surface Water Sample Location Map Figure 5.3 Dry Run Landfill Cross Section Location Map Figure 5.4A Dry Run Landfill Cross Section A-A' Figure SAB Dry Run Landfill Cross Section B-B' Figure 5.5A Dry Run Landfill Groundwater Elevation Map - October 2001 Figure 5.5B Dry Run Landfill Groundwater Elevation Map - October 1999 Figure 5.5C Dry Run Landfill Groundwater Elevation Map - October 1998 Figure 5.5D Dry Run Landfill Groundwater Elevation Map - October 1993 Figure 5.5E Dry Run Landfill Groundwater Elevation Map - April 1992 Figure 5.6A Dry Run C-8 Concentration Map Bedrock Wells - July 2000 Figure 5.6B Dry Run C-8 Concentration Map Bedrock Wells - July 1999 Figure 5.6C Dry Run C-8 Concentration Map Bedrock Wells - July 1997 Figure 5.6D Dry Run C-8 Concentration Map Overburden Wells - July 2000 Figure 5.6E Dry Run C-8 Concentration Map Overburden Wells - July 1999 Figure 5.6F Dry Run C-8 Concentration Map Overburden Wells - May 1998 Appendix 1 Consent Order APPENDIX Compilation of history data Draft 2.doc Jan. 1 4 .0 2 Wilmington, DE 009491 E ID 1 6 8 0 6 1 M A H 000433 Section 1 <CMo O S CCOO 9 UJ e o M AH000434 Main Plant and Landfills Introduction 1.0 INTRODUCTION A multi-media Consent Order was entered into between the West Virginia Department o f Environmental Protection (WVDEP), the West Virginia Department o f Health and Human Resources-Bureau for Public Health (WVDHHR-BPH) and DuPont on November 14,2001. A copy o f the Consent Order (Order No. GWR-2001-019) is contained in Appendix 1. The Consent Order identified a series o f requirements to be performed by the Parties (WVDEP, WVDHHR-BPH, and DuPont) in order to determine whether there has been any impact on human health and the environment as a result o f releases o f ammonium perfluorooctanoate (C-8), CAS Number 3825-26-1, to the environment from DuPont operations at the Washington Works main plant and the associated landfills (Local, Letart and Dry Run). The C-8 Groundwater Investigation Steering Team (GIST) was established in the Consent Order to oversee investigations and activities that will be conducted to assess the presence and extent o f C-8 in drinking water, groundwater, and surface water at and around the main plant, and the Local, Letart and D iy Run Landfills. Pursuant to Attachment A of the Consent Order, three tasks will be performed by DuPont and evaluated by the GIST, Tasks A, B, and C. This report addressed Task B. The primary objective o f Task B is to develop and implement a monitoring plan that determines the presence and extent o f C-8 in drinking water, groundwater and surface water in and around the main plant, and the Local, Letart and Dry Run Landfills, and to provide a compilation o f available groundwater/surface water monitoring results and hydrogeologic characterization data for each location. This document was prepared to meet the data compilation objective. 1.1 Document Organization Sections 2.0, 3.0, 4.0, and 5.0 present the historical data available for the main plant and the Local, the Letart and the Dry Run Landfills, respectively. Each section includes text, tables, and figures specific to the site being discussed in that section. At the end o f each section, data gaps are identified. The same outline is used for each section. Data presented in each section includes information (to the extent that information was available) as requested in Table A -l o f the Consent Order. In addition,, supplemental information is provided as needed to develop and present a site conceptual model for the four locations discussed. 1.2 C-8 Historical Laboratory Analysis of C-8 The analytical method, method detection limit, and laboratory utilized for C-8 analysis has changed over time. Prior to 1991, DuPont performed C-8 analysis at the DuPont Experimental Station in Wilmington, Delaware. In 1991, when the RCRA Verification Investigation was conducted, the analysis was contracted to the CH2MHill Laboratory in Montgomery, Alabama. Both labs used a Gas Chromatography/Mass Spectrometry based analytical method with detection limits for C-8 that ranged from 0.1 to 1.0 ug/1. Compilation of history data Draft 2.doc Jan. 1 1 .0 2 Wilmington, DE 0004 98 1-1 EID168063 M A H 000435 Main Plant and Landfills Introduction CH2MHill conducted C-8 analysis for DuPont into the fall o f 1998 when the laboratory ceased operation. At that time, DuPont had completed one round o f analysis for the RCRA Facility Investigation (RFI). The analytical work was transferred to Lancaster Laboratories, Lancaster, PA, for the RFI second round analysis in February 1999. Lancaster Laboratories continued to conduct C-8 analysis using GC/MS for DuPont until October 2001, when development and testing was initiated on a new analytical method developed by Exygen Research, Inc. (located in State College, PA) that utilizes Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS). DuPont adopted the use o f LC/MS/MS for C-8 analysis in November 2001. DuPont intends to submit to WVDEP/EPA all documentation relating to C-8 analysis using the LC/MS/MS. The analytical methodology, sampling methodology, and applicable quality control/quality assurance program will be documented in a Quality Assurance Project Plan (QAPP) to be submitted to the Groundwater Investigation Steering Team (GIST) in early 2002. 1.3 Physicochemical Data for Ammonium Perfluorooctanoate (C-8) C-8, also identified as FC-143, is a fluorinated surfactant used in the fluropolymer manufacturing at the main plant. Figure 1.0 shows the solubilities o f C7F15COOM in water as a function o f temperature (Figure 6.9 in Kissa, 1994). The following summary lists the physicochemical data available for C-8 (Kissa, 1994): Molecular Formula = CFj(CF2)6COOTIH4+ Molecular weight = 431.098 g/mole LDso acute oral rat = 680 mg/kg BCF = 1.8 pH ~ 5 (0.5% aqueous) pKa = 2.8 (-COOH) Melting Point = 56-5 8C (-COOH) COD = 700 mg/kg Koc = 25 Water Solubility > 1000 mg C-8/L Vapor pressure (at 22C) = 7.1 x 10"05 mm Hg Kraft Point = 2.5 C Critical Micelle Concentration = 33 mmol/L LDS0: Lethal Dose 50 --Dose having 50% probability of causing death DOD;o: Biochemical Oxygen Demand - Standard measurement is made for 5 days at 20 degrees C BCF: Bioconcentrarion Factor pKa: Negative log of the ionization constant - Measure o f acidity or acid strength COD: Chemical Oxygen Demand Koc: Organic Carbon Partitioning Coefficient Compilation of history data Draft 2.doc Jan. 1 1 .0 2 Wilmington. DE 000499 1-2 EID168064 M A H 000436 Main Piantane! Landfills Introduction 1.4 References Kissa, E. 1994. Fluorinated Surfactants. New York: Marcel Dekker, Inc. Compilation of history data Draft 2.doc Jan. 11, 02 Wilmington, DE oooih&o 1-3 E ID 1 6 8 0 6 5 M A H 000437 FIGURES 000501 EID168066 M A H 000438 "3T5------ r25 10 o c - J ------------- I------------- 1------------- 1-------- I 32 3.4 3.6 l/T x 10* I Figure 1.0 Solubilities of C7 F15 COOM in water as a function of temperature (Kissa, 1994). 00052 EID168067 M A H 000439 Section 2 000503 EID168068 M AH00044O Main Plant and Landfills Washington Works Main Plant 2.0 WASHINGTON WORKS MAIN PLANT Introduction..................................................................................................................................................................................................... 2-2 Environmental Setting............................................... _..................................................................................................................................2-3 Water Quality.................................................................................................................................................................................................. 2-6 Site Conceptual M odel...................................................................................................................................................................................2-7 Data Gaps.........................................................................................................................................................................................................2-8 References....................................................................................................................................................................................................... 2-8 Table 2.0 Table 2.1A Table 2 .IB Table 2.1C Tables Washington Works Main Plant Monitoring Wells Construction Data Washington Works Main Plant Analytical Data Tabic - Surface Water Washington Works Main Plant Analytical Data Tabic - Groundwater Washington Works Main Plant Analytical Data Table - Drinking/Tap Water Figure 2.0 Figure 2.1 Figure 2.2 Figure 2.3 Figure 2.4A Figure 2.4B Figure 2.4C Figure 2.4D Figure 2.4E Figure 2.4F Figure 2.5A Figure 2.5B Figure 2.5C Figure 2.6A Figure 2.6B Figures Washington Works Main Plant Location and SWMU Map Washington Works Main Plant and Local Landfill 1-ntile Radius Map Washington Works Main Plant Monitoring Well and Surface Water Sample Location Map Washington Works Main Plant Cross Section Location Map Washington Works Mam Plant Cross Section A-A' Washington Works Main Plant Cross Section B-B' Washington Works Mam Plant Cross Section C -C Washington Works Main Plant Cross Section D-D' Washington Works Main Plant Cross Section E-E' Washington Works Main Plant Cross Section F-F' Washington Works Main Plant Groundwater Elevation Map - November 2000 Washington Works Main Plant Groundwater Elevation Map - February 1099 Washington Works Main Plant Groundwater Elevation Map - November 1998 Washington Works Main Plant C-8 Concentration Map - February 1999 Washington Works Main Plant C-8 Concentration Map - November 1998 Compilation of history data Draft 2.doc Jan. 1 1 ,0 2 Wilmington, DE 000504 2-1 E ID 1 6 8 0 6 9 M A H 000441 Main Plant and Landfills Washington Works Main Plant 2.1 Introduction The Washington Works Main Plant (main plant) is located along the Ohio River in Washington, West Virginia, approximately-seven miles southwest o f Parkersburg, West Virginia (Figure 2.0). A water use and well survey is currently being conducted for the area within a 1-mile radius o f the main plant and Local Landfill property boundaries (Figure 2.1). Significant historical hydrogeologic and groundwater quality data for C-8 at the main plant is available from previous investigations that have been conducted. The most significant study was a Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) conducted in the fall o f 1998 on four Solid Waste Management Units (SWMUs) at the main plant to satisfy requirements o f the RCRA Hazardous and Solid Waste Amendments (HSWA) Permit Number WVD 04-587-2591 (DuPont, 1999). A brief description o f each o f the SWMUs investigated is presented below. SWMU locations are shown on Figure 2.0. SWMU A-3, Riverbank Landfill: The Riverbank Landfill is about 4,500-feet long and lies along the northern edge o f the site near the Ohio River. It was operated between 1948 and the late 1960s and received powerhouse ash, incineration ash, plastics, rubble, and plant trash. After closure, it was covered with 6 to 35 inches o f soil. Currently, the Riverbank Landfill is covered with dense vegetation (on the sloped area) or by buildings and pavement in the manufacturing area. SWMU B-4, Anaerobic Digestion Ponds (Digestion Ponds): Three former digestion ponds are co-located within a portion o f the Riverbank Landfill. One pond dates from the 1950s and two others from the 1970s. The ponds received waste from the fluorocarbon manufacturing process (including C-8) until 1988, when the pond contents and upper few feet of clay liner and pond berm material were removed and disposed o f off-site. The pond area was backfilled and capped with topsoil, and the area is currently vegetated with grass. SWMU C-6, Polyacetal Waste Incinerators (Waste Incinerators): The former Waste Incinerators consisted o f two brick-lined pits in the western portion o f the manufacturing area. The Waste Incinerators operated between 1959 and 1990. The Waste Incinerators have been excavated and backfilled with clean soil. SWMU H-14, Burning Ground: The Burning Ground is located in the central portion o f the manufacturing area and was operated between 1948 and 1965. Since 1990, the Burning Ground has been leveled, backfilled with clean fill and gravel, and covered by buildings and asphalt. A previous Verification Investigation (VI) found evidence o f releases o f C-8 to soil and groundwater at the Riverbank Landfill, Digestion Ponds, and Burning Ground (DuPont 1992). Little evidence o f releases were found in soil at the site o f the former Waste Incinerators. Further investigations and evaluations were performed during the RFI to determine the extent o f releases in groundwater. Compilation of history data Draft 2.doc Jan. 11. 02 Wilmington, DE 000505 2 -2 E ID 1 6 8 0 7 0 M A H 000442 Main Plant and Landfills Washington Works Main Plant Plant-wide groundwater sampling was also conducted during two separate monitoring events, the first in November 1998 and the second in February 1999, during the RFI. The sampling events focused on evaluating groundwater quality at existing and newly installed wells associated with the Burning Ground and Riverbank Landfill/ Digestion Ponds SWMUs. All plant wells sampled during the RFI were analyzed for C-8. C-8 was detected in all groundwater samples. C-8 concentrations and the extent in groundwater is discussed in Section 2.3 Water Quality. 2.2 Environmental Setting 2.2.1 Geology The geology o f the main plant is shown on six geologic cross-sections developed during the VI (DuPont, 1992) and revised based on additional findings from the RFI. The locations o f the geologic cross-sections are shown in Figure 2.3. Two east-west crosssections, A-A' and F-F', are shown on Figures 2.4A and 2.4F. Four north-south crosssections, B-B', C-C', D-D', and E-E' are shown on Figures 2.4B, 2.4C, 2.4D and 2.4E, respectively. The cross-sections were developed from detailed geologic logs recorded during the VI and RFI, and from less detailed historic geologic logs from test and production wells and geotechnical borings drilled in the late 1950s through the early 1980s. Some monitoring wells shown in Figure 2-3 were later abandoned. The current site map (Figure 2.2) shows the monitoring wells that currently exist at the site. The main plant rests on Quaternary alluvial terrace deposits in the Ohio River Valley. The alluvial terrace is topographically flat and lies approximately 50 feet above the Ohio River, which flows east to west past the main plant (see Figure 2.0). The alluvial terrace is underlain by a flat, river-scoured bedrock surface o f the Dunkard Series that rises steeply and outcrops in the southern edge o f the site to form the valley wall. The Quaternary alluvium ranges from 60 to 100 feet in depth and consists o f coarsening downward unconsolidated river deposits o f poorly to well-sorted, brown and gray sand, silts, clay and gravel. The Dunkard Series bedrock consists primarily o f red and varicolored sandy shale; gray, green and brown sandstone; and minor beds o f coal, claystone, black carbonaceous shale, and limestone. The average river water elevation is about 580 feet above Mean. Sea Level (MSL) and the elevation o f the Ohio River terrace deposits under the main plant are about 630 feet above MSL. Due to riverbank undercutting, some slumping o f clay and silt exists along the northern boundary o f the main plant along the river's edge. Figure 2.4C shows an example o f the relationship o f fill and clay layers along the riverbank. 2.2.2 Hydrology, Hydrogeology and Groundwater Flow Hydrology Regional water needs are primarily satisfied by the Ohio River and Little Kanawha River near Parkersburg. These sources provide water to the cities o f Parkersburg, Compilation of history data Draft 2.doc Jan. 1 1 .0 2 Wilmington. DE 000506 2 -3 E ID 1 6 8 0 7 1 M A H 000443 Main Plant and Landfills Washington Works Main Plant West Virginia and Belpre, Ohio. In less populated areas (i.e., near the main plant), the local communities receive water from small local water companies that obtain their water from production wells screened in the Quaternary river alluvium. Surface water at the main plant discharges through drains and storm sewers, and drainage swales. Seeps located along the riverbank may originate from precipitation that has infiltrated topsoil or fill and that flows along the top o f the underlying shallow clay and discharges along the riverbank. Two drainage swales, one located in the facility's southwest comer, and the other located on the extreme eastern end o f the facility, convey surface runoff during rainy weather to the Ohio River. During dry weather, the drainage swales are dry. Hydrogeology Regional groundwater supplies are obtained from the Dunkard Group bedrock and Ohio River alluvial terrace deposits. The saturated portion o f the Ohio River alluvial terrace deposits comprise the principal regional aquifer used for water supply purposes. Production wells completed in this aquifer have been known to yield up to 500 gallons per minute (gpm) (Schultz, 1984). Based on these high yields, numerous industrial and commercial water supply companies obtain water from the alluvial aquifer. The yield from alluvial aquifer wells is related to the well's position with respect to the river, as well as formation grain size and thickness. The Ohio River alluvial terrace deposits contain a single key aquifer underlying the main plant. The water table occurs at a depth o f about 60 to 70 feet below ground surface in the main plant area. The saturated zone is approximately 30 to 40 feet thick, extending to the surface o f the underlying Dunkard Group. The on-site production water wells completed in the site aquifer yield 200 to 450 gpm. The underlying Dunkard Group is not a major aquifer. The upper zone o f the Dunkard Group (Washington Formation), which consists primarily o f shale and silt, likely bounds the lower extent o f the site aquifer. In addition, regional groundwater communication between the Ohio River and bedrock will likely result in upward gradients to the alluvial aquifer. Groundwater quality in the alluvium in this region tends to be naturally poor, having the highest median chloride, sulfate, hardness (as calcium carbonate), iron, and manganese concentrations of all hydrogeologic units in the region (Schultz 1984). Water from the alluvium generally is a calcium bicarbonate type, with near neutral pH and high dissolved solids content. Natural recharge to the alluvial aquifer comes from various sources, including: Infiltration o f precipitation falling directly on the alluvium Lateral movement o f the river water through the alluvium via permeable sand and gravel zones Seepage from stream tributaries that discharge to the Ohio River The maximum amount o f water available to the alluvium depends on the degree o f hydraulic connection to the river. The degree o f hydraulic connection is a function o f the permeability and thickness o f the riverbed, permeability and thickness o f the alluvium, and hydraulic gradient between the groundwater and the river. Pumping o f on-site active Compilation of history data Draft 2.doc Jan. 11. 02 Wilmington, DE 000507 2 -4 E ID 1 6 8 0 7 2 M A H 000444 Main Plant and Landfills Washington Works Main Plant well fields near and parallel to the river (i.e., the Ranney Well, the DuPont-Lubeck Well Field, and the East Well Field shown in Figure 2.2) lowers the groundwater level in the alluvial aquifer to below river stage. This induces water from the river to flow into the alluvium toward the wells, which replaces water pumped from storage in the aquifer, and helps sustain high-yield pumping wells. Groundwater Flow Groundwater generally flows to the south-southwest in the alluvial aquifer. However, groundwater elevations, flow directions, and flow rates on-site are strongly influenced by the Ohio River and by pumping o f on-site production wells. The on-site production wells include the Ranney Well, a radial collector well which pumps 800 to 1,000 gpm; the seven wells in the East Well Field, which pump a combined average rate o f 2,000 gpm; and the five DuPont-Lubeck wells, which pump about 700 gpm combined. Groundwater elevation contour maps for the alluvial aquifer developed from data measured in November 2000, February 1999, and November 1998 are presented as Figures 2.5A, B, and C, respectively. The direction o f groundwater flow is indicated by the flow arrows. As shown on the groundwater elevation contour maps, groundwater flow in the northeast part o f the site is toward the East Well Field wells. In the northcentral portion of the site, groundwater flow is toward the Ranney Well. In the central and western portion o f the site, groundwater flow is south-southwest towards the DuPontLubeck Well Field. Pumping o f the production wells (Ranney Well, East Well Field, and the DuPont-Lubeck Well Field) eliminates off-site migration o f impacted groundwater that may originate from the SWMU areas. Additional groundwater elevation data was obtained from the General Electric (GE) property located to the west o f the main plant. Data from the main plant and GE were used in calibrating the Washington Works groundwater model (DuPont, 1999). The groundwater model conclusions indicated that groundwater from the main plant area is contained to the DuPont property by operation o f the site production wells. In a 1990 hydrogeologic assessment, production well specific capacity testing o f the DuPont-Lubeck Well Field and the East Well Field was conducted. The results were used to calculate the transmissivity and the hydraulic conductivity o f the alluvial aquifer (DuPont 1990). In the vicinity o f the DuPont-Lubeck Well Field, transmissivity values ranged between 114,900 and 127,500 gallons per day per square foot (gpd/ft2). In the vicinity o f the East Well Field, the transmissivity values ranged between 16,050 and 50,000 gpd/ft2. Hydraulic conductivity values were calculated from the transmissivity values for the East Well Field. For Wells AX13-PW01 and AZ13-PW01, the hydraulic conductivity values ranged from 0.013 to 0.055 centimeters/second (cm/sec) and from 0.01 to 0.049 cm/sec, respectively. Using the hydraulic conductivity values from the 1990 study and the hydraulic gradient values determined from groundwater elevations measured in 1990 and assuming an effective porosity value for sand and gravel o f 35 %, the groundwater flow velocity for several well pairs was calculated. The groundwater flow velocity was estimated at 5 feet/day (fl/d) between monitoring wells T13-MW01 and L18-MW01 in the southwest portion o f the site. A groundwater flow velocity o f 3 ft/d was estimated between monitoring wells P06-MW01 and K14-MW01 in the western central portion o f the site. Compilation of history data Dratt 2.doc Jan. 11, 02 Wilmington, DE 000508 2 -5 E ID 1 6 8 0 7 3 M A H 000445 Main Plant and Landfills Washington Works Main Plant In the eastern portion o f the site, a groundwater flow velocity o f 2.5 ft/d was estimated for the site aquifer between monitoring wells AL10-MW01 and AO09-MW01. Groundwater seeps at the Riverbank Landfill were identified and sampled during the VI (DuPont 1992). An active French-Drain groundwater collection has been in operation at the Riverbank Landfill since 1991. The RFI verified that the collection system effectively captures water at the seep area. 2.3 Water Quality 2.3.1 Surface Water Quality Historical surface water C-8 concentrations are presented in Table 2.1 A. Surface water sample locations are shown on Figure 2.2. Surface water C-8 concentrations were measured in 2000 and 2001 at two outfalls, 002 and 005 and at two river locations. The outfalls have been sampled monthly since February 2001. Outfall 005 C-8 concentrations have ranged from 1.43 ug/1 to 199 ug/1, while Outfall 002 C-8 concentrations overall have been much lower, ranging from 0.436 ug/1 to 8.54 ug/1. In general, Outfall C-8 concentrations have significantly declined in 2001. This is the result o f installation of a carbon adsorption treatment system in the fluropolymers process. The system is designed to remove a major percentage o f C-8 from the process wastewater. 2.3.2 Groundwater Quality Concentrations o f C-8 in groundwater sampled at the main plant have been evaluated since 1991 (Table 2.1 B), however, the wells sampled and the sampling frequency has been variable. Some wells have been monitored annually since 1996 and others have been monitored quarterly starting in January 2001. Two plant-wide groundwater sampling events were conducted as part o f the RFI (November 1998 and February 1999) and are discussed below. The sampling events focused on evaluating groundwater quality from existing and newly installed wells associated with the Burning Groimd and Riverbank Landfill/Digestion Ponds SWMUs. All plant wells sampled during the RFI were analyzed for C-8. At the Riverbank Landfill/Digestion Ponds area (in the western portion o f the Riverbank Landfill), C-8 was detected in groundwater and previous seep samples. Figures 2.6C and 2.6D depict the well locations and results for C-8. Measured concentrations ranged from <0.1 to 13,600 pg/L. Concentrations were below 40 pg/L in 28 o f the 37 wells sampled; in the other 9 wells, maximum concentrations ranged from 380 to 13,600 pg/L. The highest concentrations were measured in monitoring wells P04-MW02 and R04-MW02, near the Digestion Ponds area. The RFI C-8 concentration values were utilized for contouring. Isoconcentration maps were prepared and are presented in Figures 2.6A and 2.6B. Compilation of history data Draft 2.doc Jan. 11. 02 Wilmington. DE 2-6 000509 _______________ E ID 1 6 8 0 7 4 M A H 000446 Main Plant and Landfills Washington Works Main Plant 2.3.3 Drinking/Tap Water Quality Production Well AM07-PW01 (historically known as well 336) supplies potable water to the main plant. C-8 concentrations in drinking/tap water have been measured at four distribution points on the plant periodically since May 1999 (Table 2.1C). Concentrations ranged from 0.213 ug/1 to 0.589 ug/1. C-8 concentrations detected at three sampling points in the distribution system on October 11, 2001 were 0.507, 0.45, and 0.423 ug/1, respectively. No obvious trends are seen in the data. 2.4 Site Conceptual Model The main plant site conceptual model describes the potential exposure routes for current and future human and ecological receptors. Potential exposure routes were evaluated and classified as complete or incomplete. Direct exposure to C-8 bearing materials contained within the SWMUs is minimal or non-existent, because these materials have been removed and regraded or paved (Burning Ground, Waste Incinerators, and Digestion Ponds) or covered and vegetated. Therefore, contact with these materials is considered to be an incomplete exposure pathway. A large portion o f the plant site is covered with asphalt and concrete. Hence surface water contact with C-8 impacted soils or groundwater is not likely in these areas. Therefore, surface water contacting C-8 impacted soils is considered to be an incomplete exposure pathway. Much o f the precipitation falling on site is routed toward drains and storm sewers, which ultimately discharge into the Ohio River. Precipitation falling on the riverbank slope either percolates into the soil or runs off to the river. The seeps that occur in places along the riverbank are probably caused by percolated water that accumulates above the slumped, low-permeability clay and silt o f the Ohio River deposits that underlie topsoil and fill along the riverbank. Contact with impacted seep water is considered to be an incomplete exposure pathway due to the active french-drain groundwater collection system. Direct exposure to groundwater impacted by C-8 is also considered to be an incomplete pathway because groundwater is located at about 60 feet bgs. The only potential contact route for groundwater is via contact with water pumped from production wells. Water pumped from production wells is used for two purposes, supplying drinking water and providing industrial process water. Well AM07-PW01 is one o f three production wells that provides drinking water to the main plant. Other w'ells are AO08-PW01 and AQ09-PW01. AM07-PW01 was sampled eight times. Measured concentrations o f C-8 in this well suggested that this exposure pathway is considered to be complete. However, average concentrations o f C-8 in drinking water at point o f use (which is a mixture o f water from the three wells) will be lower than the maximum concentrations detected in any single well. Contact with impacted drinking/tap water is a complete exposure pathway. C-8 was detected in production wells providing industrial process water (K16-PW01, V05-PW01, and L04-PW01). The maximum concentration o f C-8 was detected in well K16-PW01 (16.2 ug/1). Water from these wells is not used for drinking, but rather for industrial processes including non-contact and contact cooling water, fire water, process Compilation of history data Draft 2.doc Jan. 11,02 Wilmington, DE 000510 2-7 E ID 1 6 8 0 7 5 M A H 000447 Main Plant and Landfills Washington Works Main Plant water, conversion to demineralized water to generate steam, and/or consumption in the manufacturing processes. There is a potential for limited contact, however, this contact is expected to be minimal. Average concentrations o f C-8 in process water at the point o f use (which is a mixture o f water from several production wells) will be lower than maximum concentrations detected in any single well. Therefore, while this exposure pathway is complete, it is considered to be minimal. The RFI ecological evaluation focused on identifying whether significant ecological resources may be exposed to site-related constituents released from the SWMUs. This evaluation concluded that surface soil at the Riverbank Landfill/Digestion Ponds is the only potential ecological exposure medium within the RFI study area. Surface water contact with C-8 impacted soils or groundwater is not likely because the Waste Incinerators and Burning Ground SWMUs are covered with gravel, asphalt, or buildings and do not provide ecological habitat. Subsurface soil (greater than 2 feet) and groundwater are not exposure media o f concern for ecological receptors, and groundwater does not discharge to surface water at the site. 2.5 Data Gaps The following data gaps were identified for the main plant: Additional monitoring wells are needed to further delineate C-8 concentrations in groundwater and to evaluate groundwater flow directions, particularly for groundwater flow in the bedrock below the unconfined alluvial aquifer. Continued refinement o f the groundwater model for the main plant is required to reevaluate that groundwater capture by the pumping wells is occurring at the site and that no off-site migration o f C-8 impacted groundwater is occurring. Surface water quality in the Ohio River should be evaluated. A separate work plan is currently being designed to address this issue. Activities to fill the data gaps will be proposed and discussed in the work plan. 2.6 References DuPont. 1990. Washington Works 1990 Preliminary Hydrogeologic Assessment. Solid Waste & Geological Engineering Department. ______ . 1992. Verification Investigation E.l. DuPont de Nemours Co. Washington Works April 1992. (Vol. 1). ______ . 1999. RCRA Facility Investigation Report, DuPont Washington Works, June 3 0 ,1 9 9 9. Corporate Remediation Group. Haskell Laboratory. 1991. Ammonium Perfluorooctanoate (FC-143). Compilation of history data Draft 2.doc Jan. 1 1 ,0 2 Wilmington, DE 000511 2 -8 E ID 1 6 8 0 7 6 MAHOOQ4 48 Main Plant and Landfills Washington fcfcs Main Plant Schultz, R.A. 1984. Groundwater Hydrology o fthe Minor TributaryB tuim sfthe Ohio River, West Virginia Compilation of history data Draft 2.doc Jan. 1 1 ,0 2 Wilmington, DE 000512 2 -9 E ID 1 68077 MAH0004 4 9 TABLES I 000513 ,EID168078 M A H 000450 Table 2.0 Monitoring Well Construction Data DuPont Washington Works Main Plant Washington, WV Monitoring Wells New ID Old ID Q04-MW02 Q05-MW0I P06-MW02 P08-MW0) N13-MW01 MI6-MW01 AO08-PW0I AQ09-PW01 ATIO-PWOI AVI l-PWOl AX13-PW01 AMO7-PW01 AZ13-PW01 L04-PW01 L17-PW01 K18-PW01 K19-PW01 KI6-PW01 J17-PW0I V05-PW0I J08-MW01 Q07-MW01 Z07-MWOI GlO-MWOl TL3-MW01 U16-MW01 A009-MW01 L18-MW01 V09-MW01 N04-MW01 P06-MW01 AR09-MW01 AXI2-MW01 AG07-MW0I AJ06-MW01 A008-MW01 Y05-MW0I AC05-MW01 ALIO-MWOI Ron's MW-1 Ron's MW-2 Ron's MW-3 Ron's MW-4 Ron's MW-5 Ron's MW-6 331 332 333 334 335 336 337 GALLERY Ll(35l) L2(352) L3(353) L4(354) L5(355) RANNEY TW-l (tw-28) TW-20 TW-21 (307) TW-22 TW-23 TW-24 TW-25 TW-26 TW-27 TW-3 (pw-3) TW-32 TW-33 TW-38 TW-39 TW-40 TW-41 TW-46 TW-48 TW-5 TW-60 TW-6I TW-E4 TW-E5 TW-E6 TW-M1 Surface Elevation (feet) 629.39 598.76 629.29 630.82 625.87 627.14 632.91 634.36 634.37 633:49 630.69 634.26 628.04 589.75 633.93 634.92 634.2 623.24 624.78 632 630.21 630.35 632.49 631.4 632.69 638.23 632.89 635.82 628.5 594.48 630.63 635.27 635.23 632.87 635.09 636.02 631.16 635.22 631.61 Total Depth (feet) 71 42 71 75 70 70 95 96 97 93.9 90 96 92 92 95.21 101.4 102.69 108.23 98.5 105.27 101.16 101.61 Well Slot Diameter Size (inches) (inches) 2 2 2 2 2 2 18 18 18 18 " 18 18 18 18 18 18 18 NA 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 4 6 4 Screen Length (feet) 10 10 10 5 5 10 20 20 20 19 13 20 20 NA 18 1 20 20 20 20 20 20 20 20 20 Elevation of Screen Interval (feet) 566.0 - 556.0 567.0 - 557.0 567.0 - 557.0 559.0 - 554.0 560.0 - 555.0 565.0 - 555.0 558.7 - 538.7 553.8 - 533.8 553.5 - 533.5 555.7 - 536.7 556.0 - 543.0 555.0 - 535.0 555.0 - 535.0 542.0 - 541.0 555 - 535 550 - 530 550 - 530 550 - 530 550 - 530 550-530 550 - 530 550-530 550-530 Page 1 of 2 000514 _EID168079 M A H 000451 Table 2.0 Monitoring Well Construction Data DuPont Washington Works Main Plant Washington, WV Monitoring Wells New ID Old ID I07-MW01 K14-MW0I D08-MW01 F06-MW0I U03-MW01 U05-MW02 U05-MW0I L04-MW01 AA04-MW0I AA05-MW01 AB07-MW02 AC07-MW02 AEI1-MW0! AI06-MW01 E13-MW01 G17-MW01 L06-MW01 M04-MW02 M04-MW03 N04-MW02 N05-MW0I P04-MW02 P05-MW02 R04-MW02 S05-MW02 U04-MW01 V06-MW01 W05-MW01 Y14-MW! Z06-MW02 Z07-MW01 Z09-MW0I TW-M2 TW-M3 TW-M4 TW-M5 TW-M6 TW-N2 TW-P12 TVV-Wl WOO-577 TW-70 TW-71 TW-72 TW-73 TW-74 TW-75 TW-76 TW-77 TW-78 TW-79 TW-80 TW-81 TW-82 TW-83 TW-84 TW-85 TW-86 TW-87 TW-88 TW-89 TW-90 TW-91 TW-92 TW-93 Surface Elevation (feet) 610.23 627.34 600.67 601.14 592.44 631.17 632.11 Total Depth (feet) 97.34 62.8 102.il Well Slot Diameter Size (inches) (inches) 4 4 4 4 6 6 6 Screen Length (feet) 20 20 20 597.4 630.8 630.6 633.2 629.51 634.04 623.5 630.5 629.85 593.5 593.6 593.6 633.48 590.6 631.68 593.2 631.18 593.1 629.93 630.25 629.93 640.1 629.64 630.7 43 70 72 74 72 72 74 80 77 25 26 26 82 28 80 28 78 27 77 76 90 72 74 70 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 t o 10 10 10 10 10 Elevation of Screen Interval (feet) 550 - 530 550 530 550 - 530 564.4 - 554.4 570.8 - 560.8 568.6 - 558.6 569.2 - 559.2 567.51 -557.1 572.04 - 562.04 559.5 - 549.5 560.5 - 550.5 562.85-552.85 578.5- 568.5 577.6 - 567.6 577.6- 567.6 561.48-551.48 572.6 - 562.6 561.68-551.68 575.2 - 565.2 563.18 - 553.18 576.1 - 566.1 562.93 - 552.93 564.25 - 554.25 549.93 - 539.93 578.1 - 568.1 565.64 - 555.64 570.7 - 560.7 M16-MW0I N13-MW01 P08-MW0I Q04MW02 TW-55 TW-54 TW-53 TW-50 627.14 625.87 629.29 598.76 Red and Italics - approximate - taken off cross-section Bold -- Taken from RFIWP Page 2 of 2 000515 EID168080 M A H 000452 Table 2.1A Summary of Analytical Results: C*8 in Surface Water Samples DuPont Washington Works Main Plant Washington, WV Sample OUTFALL 002 OUTFALL 005 RIVER BELOW 005 RIVER BELOW PAGES RUN Date 10/25/01 9/19/01 7/11/01 6/14/01 5/31/01 4/11/01 3/21/01 2/14/01 10/25/01 9/19/01 8/30/01 7/11/01 6/14/01 5/31/01 4/11/01 3/21/01 2/14/01 6/14/01 6/14/01 J = estimated value (below laboratory quantitation limit) C-8 (usl\) 2.8 0.118 0.558 0.594 0.436 1.5 8.54 1.74 65.7 2.86 2.16 120 7.4 1.43 4.31 199 153 0.034 J 0.075 J j 00051 EID168081 M A H 000453 Table 2.1 B Summary of Analytical Results: C-8 in Groundwater DuPont Washington Works Main Plant Washington, WV Sample AA04-MW01 AA05-MW01 AB07-MW02 AC07-MW02 AE11-MW01 AI06-MW01 AM07-PW01 AO08-PW01 AQ09-PW01 E13-MW01 F06-MW01 G17-MW01 K16-PW01 L04-PW01 L06-MW01 L17-PW01 Date . 2/6/99 11/12/98 11/12/98 (dup) 2/4/99 11/11/98 2/4/99 11/16/98 2/4/99 11/16/98 2/2/99 11/10/98 2/3/99 11/16/98 11/20/00 8/16/00 5/12/99 2/3/99 11/18/98 6/19/98 6/2/97 4/2/96 11/20/00 11/20/00 (dup) 8/15/00 5/12/99 6/19/98 6/2/97 4/2/96 10/11/01 5/12/99 5/12/99 _2_/2_/9_9_ 2/2/99 11/11/98 5/12/99 2/2/99 11/11/98 11/20/00 2/9/99 11/18/98 7/11/01 4/11/01 11/20/00 2/7/99 11/18/98 11/18/98 (dup) 2/5/99 11/13/98 7/11/01 4/11/01 9/14/00 6/3/99 2/9/99 11/18/98 6/2/98 5/29/97 4/11/96 2/16/94 | || 1 I I C-8 (ug/l) 5.43 <0.1 0.42 1.46 0.77 0.535 <0.2 I 0.356 0.79 0.69 L 0.41 0.13 B <0.1 0.24 0.071 J 0.578 0.082 B 1.9 L 0.4 0.79 0.48 0.4 0.26 0.167 0.307 1 0.55 0.52 0.498 1.45 0.882 j0 .5 9 1 0.35 L <01 2.47 2.11 L 13 7.5 16.2 0.46 L 0.202 3.99 13.8 5.89 7.9 J 3.9 J 4.91 870 2.31 1.58 0.819 1.63 2.76 0.33 16 7.9 3.7 2 | 1 | 000517 EID168082 M A H 000454 Table 2.1 B Summary of Analytical Results (con't.): C-8 in Groundwater DuPont Washington Works Main Plant, Washington, WV Sample M04-MW02 M04-MW03 M16-MW01 N04-MW02 N05-MW01 MW-AJP MW-MGM MW-TWW MWBG N13-MW01 P04-MW02 P05-MW02 P06-MW02 . P08-MW01 Q04-MW02 Q05-MW01 R04-MW02 V05-PW01 T13-MW01 U04-MW01 U16-MW01 , S05-MW02 voe-M woi W05-MW01 Y14-MW01 Z06-MW02 Z07-MW01 Z09-MW01 Date 2/7/99 11/12/98 2/7/99 11/12/98 2/3/99 11/10/98 1/25/01 1/25/01 (dup) 2/7/99 11/12/98 2/5/99 11/13/98 4/18/96 4/18/96 4/18/95 4/2/96 2/2/99 11/11/98 1/25/01 2/6/99 11/12/98 2/5/99 11/13/98 2/5/99 11/13/98 2/4/99 11/13/98 2/4/99 11/13/98 11/13/98 1/25/01 2/6/99 11/12/98 7/11/01 4/11/01 11/20/00 2/7/99 2/7/99 (dup) 11/18/98 2/3/99 2/3/99 (dup) 11/17/98 2/6/99 11/12/98 5/11/00 5/20/99 6/19/98 2/5/99 11/13/98 2/4/99 11/16/98 2/6/99 11/17/98 2/2/99 11/10/98 2/4/99 11/16/98 2/4/99 11/16/98 2/6/99 11/17/98 C-8 (ug/l) 17 0-2 21.1 <0.1 3.66 L 0.86 698 696 329 380 815 13 <0.4 0.69 0.85 <0.1 29.6 L <0.1 12600 13600 8300 434 1200 414 31 43.4 36 994 660 38 13800 9420 1300 11.4 5.48 13.7 12.4 3.95 0.66 L 0.64 L 1.30 L <0.1 R 4.2 1.6 4.7 2 11 174 690 1.91 1.7 0.729 0.31 4.95 L 12 0.803 4.5 2.05 3.8 2.74 <0.1 R J 00051 EID168083 M A H 000455 Table 2.1 B Summary of Analytical Results (con't.): C-B in Groundwater DuPont Washington Works Main Plant, Washington, WV Sample RBLMW1 RBLMW2 RBLMW3 RBLMW4 RBLMW5 RBLMW6 RBLMW7 RBLMW8RBLMW9 i RBLMW10 RBLMW11 RBLMW12 BGMW2 BGMW3 BGMW5 ADPMW 1 ADPMW 2 ADPMW 3 Date 12/5/91 12/5/91 (dup) 12/11/9112/11/91 (dup) 12/11/91 12/5/91 12/10/91 11/21/91 11/21/91 11/21/91 (dup) 12/10/91 12/10/91 11/20/91 11/20/91 12/10/91 12/13/91 12/13/91 12/13/91 (dup) 12/11/91 12/6/91 12/6/91 12/6/91 R = unusable data result (relative to QA/QC) J = estimated value (below laboratory quantification limit) L = possible low bias result (relative to QA/QC) B= compound detected in QC blank < = Non-detect at stated laboratory method detection limit C-fl (ug/l) 140 140 65 67 7100 550 1300 3300 46 52 2.4 3.4 14 47 4.6 2.3 4 3.6 5.5 7800 25 20000 00051B EID168084 M A H 000456 Table 2.1 C Summary of C-8 Analytical Results: Drinking/Tap Water Samples DuPont Washington Works Main Plant Washington, WV I Sample BLDG 1 MAIN BLDG 231 BLDG 293 BLDG 5 Date 10/11/01 10/11/01 (dup) 8/15/00 10/11/01 5/12/99 5/12/99 (dup) 10/11/01 5/12/99 5/12/99 C-8 (ug/l) 0.507 0.471 0.589 0.45 0.306 0.269 0.423 0.496 0.213 I I 00052 EID168085 M A H 000457 FIGURES i 000521 EID168086 M A H 000458 SITE LOCATION AND SWM MAP Corporate Remedatkm Groif> An AUianc betueen DuPont snd UJtS D iamond Borley Milt Plczo. Building 27 Wilmington, Delaware 19805 D uPont W ashington Works Main P lan t W ash in g to n , W est V irg in ia SC* Nc4 to Beota " " /0 2 7 / 0 1 0C9WCB DO. acau U. HOUUWY DMOM CSL wmD CW FU N a 7422A001 nounc 2 .0 000522 -------- EID168087 M A H 000459 M A H 000460 M AH0004 61 M AH0004 62 M U h t WOW# 1t*tO M r gflN'TOn u l l < n - 7. S)i I Hf.A'A. '^'ynl^favrt -iff V! (*tF*i y 1 -" IT 1<111 Vit thin,,fO l / l ' A A' > WOSS SCT6N UNC m D_a>* 9 9 Co<OQO 9 Cn 10 W S C A 1. f 750 3C 3 5 C'Cna d l <8 ) ^ C o r p o r a to R e m e tfia tio n G ro u p tllm n t* btu/*tn Dufirmt and URS Dt*mvn4 f t o 'l t y M'H Plo ro . B u iid ^ g 2 7 w iim ino w ', Odowore '9 W 5 C R O S S -S E C T IO N LOCATION MAP D uP ont W ashington Works M oin Plant W a s h in g to n , W est V irg in ia C T ----------- JS jr*t Ali jnws 000528 EID168091 M AH0004 63 M AH0004 64 m oe lO0O(ra0o3)i o o Cn 10 000528 EID168093 M AH000465 M AH000466 North D 640- B G M W -2 Z07-MW01 (TW-22) B --3 8 B D -2 2 620- i2n , 600- g2 I<>-- 5 8 0 w 560 -- 540- 20 FT 520 L285 FT Topsoil -- OL FIN f } Sond -- SM.5C.SP rrm sut - ml Send ond Grovel - SW.GP.GW.GM LEGEND: PT I ^ ' Bedrock [Z3 C loy - CL_ S ta tic W ater Level, Dec. 1991 A pp ro xim a te Geologic C ontact S ta tic W o tcr Level, Inferred G ro un d w ate r Flow D irection mo o Ooo(AOa) Vi K South D' T B -8 0 'r~ ' "" CMV-S <s w b > ^ Corporate Remediation Group /In 41/tvxcr Oul'ont and URS Ivamond Horie/ m<ii Pio: q. Building 27 vv.imrfvqlo1", 0eioo'e '9505 C R O S S-SE C TIO N D -D ' DuPont Washington Works Main Plant Washington, West Virginie n North E BGMW-1 BGMW-7 South E' 120 FT nm Topsoil - l r I Sand - SM.SC.SP [e n Sand and G rave l - khi 117171 S i lt - M L SW .GP.GW .CM LEGEND: E S P e a t - PT I 7 1 B edrock r m C la y - CL S ta tic W ater Levs!. Dec. 1991 A p pro xim ate Geologic Contact S ta tic Wotnr 1aval. Inferred 5 ^ Groundwater Flow Direction m o 0o0<>00 <9 o in w0 1 e Wi-n CliVS tw ''TO*PiC3itVC' l>! C R O S S -S E C TIO N E - E ' Corporate Remediation Group 4n 4Hmnr rn PvP*nt and VffS ih a m o n i 0O 'ly M<ll ri02O. Bwi'nq 27 Inn.ncton Oe'owGre 1^805 O cP ont W ashington W orks M ain P ln n t W a s h in g to n , W est V irg in io r-- r - M AH0004 67 20 FT 10 530- :.<v ;:.o;;cv./, ci._ d .. ; ......, ;.... .... ,,...:Dn. ..\. ,;.,O.:...o: o;e;.<.0\. ;o ' ; \ : . \ ;c>\..-'. \ . ;o " o ' ;o. 0 u . K - O' : u \ o - ; J . o ' 7 ' !o . . 7 . . p - .o u " ' -'.cv (\ ' fv r\ **n,' c\ ' r\- a ' K- r\ o: . o ' : o`o . o .0 : o ' ; -`o : ' o'.: e 'c>. 'o '. : > 9 ;.: p :\ 0 0 c % - o 0 * - Q U A T E i ^ N A R ^ A U u y i u ^ ^ 0 0 . 0 :o ' .; - 'cv. C i' ' ' rivO 'C y n 0 r> o . o ' ; o :: . ,p\o:. oc= p o so ,o \ o'o . - o o : :.o'p .0.0 ' --^ 0 7' - :- 77- 0 0 r ' ? .* 0' " -'7' - O'-'' - 0 ' -.0' '-'0; ' '.0;.^. 70 .' -.0, 0 --- -- ---------:---:-- ^ ^ ----------*' 0' ^ ' 0' c?.' ' .- 7 P.7-,0 0.' o\0o . 5 0 0 FT rOT! Topsoil - OL f I Sand -- SM.SC.SP m Sand and G ravel - g g Fill B11i 1 S ilt -- ML SW .G P .G W .G M LEGEND: i Zl fT ^ P e at - PT Bedrock Clay - Cl | f S ta tic W ater Level, Dec. 1991 ____ A p p ro x im a te G eologic C o n ta ct ------ S ta tic W ater Level, Infe rre d --$ 5 ^ G ro un d w ote r Flow D irectio n nc'.ofc *>l\ <.C-IC *""*1 U > Corporate Remediation Group 4n Alitane* b*tui*n PuPtnt and UPS Diamond Buriey Mi*i Pia*o, B i/td.n g 27 WiimHcto'. eiowor't 198C5 C R O S S -S E C TIO N F - F ' D uP ont W nshtngtnn W ork* Mota P lo n t W a s h in g to n , W est V irg in io M ( I * - 1 u m /e i 1 ' j TM 1 2.A* M AH000468 m oe oe o<o0D>9 Cfl W M 04--MW 02 ^pos-uwoi ^ MONITORING w e l l ^17-PWOI $ = PR O D UC TIO N W E LL < a ---------------- A P P R O X IM A T E D IR E C T IO N O F G RO UNDW ATER FLOW 564---------- = G R O U N D W A T E R E L E V A T IO N C O N T O U R , APPROXIM ATE (NOVEMBER, 2 0 0 0 ) m o O0o(O0) e Cn W to SCALE 700' PCWJ MM CKDO MKMtcecsaM) ASH WfmwWCBIgFmCMi) C orporate Remediation Group An ihono ( i l w n n Duf-nnl and UftS Dtamena Barley M>H PlQiO. Building 27 Wlirriinalan. De'ow or* >9605 GROUNDWATER ELEVATION CONTOUR MAP - NOVEMBER 2000 D uP ont W ashington W ork M ain P la n t W a s h in g to n , W est V irg in ia *1 1 TAUfOOS 1 2.4* M AH0004 69 M AH000470 <$r = APPROXIM ATE D IR E C T IO N O F G R O UND W ATE R PLOW 5 6 4 ------------- GROUNDWATER E L E V A T IO N C O N T O U R (F E B R U A R Y . 1 9 9 9 ) m o o at 09 o<o cn w0 9 w OCL VW>TO<TMjcnt^ SCALE 700' GROUNDWATER ELEVATION CONTOUR MAP - FEBRUARY 1999 Corporate Remediation Qroup An /Hum frfhtion URS Bismand D v P o n t W ash in g to n W orks Moin P la n t Washington, West Virginia B o fi*y U iii Ploro. 27 _________W ilfviiroiofl, Q elcw o' 1980S_________ n/a/ot MtMtt 258 M AH000471 A P P R O X IM A T E D IR E C T IO N O F G RO UND W ATER FLOW 5 3 4 . ----------- G RO UND W ATE R E L E V A T IO N C O N T O U R (NO VEM BER. 1 9 9 8 ) mo oo O09 oto to o cn w rf* nwfflun SX "**** SCALE 700 700' > ^ C o rpo rate Remediation Group Jn itUisnc* t/ttuinn DxtPDnJ and VUS D\mtfnd 8orl*y K<iii P)aro. 8u`lfl<ng 27 Wiim.rtijiort, Odlnwof 19805 GROUNDWATER ELEVATION CONTOUR MAP - 1998 D uPont W oshington W orks M ain P la nt W a sh in g to n , W est V irg in ia *. -. | ii/wybi | Maws | 3.SC EID168100 LEGEND , OOS-MW01 vOS-fVKil = E X IS TIN G W E L L Ct = P R O D U C T IO N W E L L s = C --8 C O N C E N T R A T IO N = EX|ST,NG WELL (u g /l) -- 10-- = C --8 IS O C O N C E N T R A T IO N L IN E O O O Crt w Cn cxvcna SX ca TT* A91 AT'WKtMODWSmiCr9h1 SCALE 700 700' fflS> ^ C o rpo rate Remediation Group ^rv Kiliane frrhuttn ih iP vn t #nd U/fS O iv n m A BoMey M'il Plo/o, Building 27 Wliminqlon, D 'a0' 19805 C - 8 IN GROUNDWATER FEBRUARY. 1999 DuPont W ashington W orks M ain P lant W o s h in g to n . West Virginio Mi :m U jnauv A* afro* 1 11/12/01 7*U 1 7 BA M AH000473 LEGEND . ow-ww a MONfTORING WELL -O PRODUCTION W ELL -'* = C - 8 C O N C E N T R A T IO N ( u g / l ) eu- wwdi = WONITORING W ELL -- 10-- = C--8 IS O C O N C E N T R A T IO N LIN E o mo oa a0>0 o Cn W o 0) SCALE 700 700' C o rpo rate Remediation Group AHwne C*uflont an<( URS S o rie y Mtii P la c e , 0uiiO*nq 27 ________ W ilmington, Q eigwq^c '9 0 0 5 _________ C - 8 IN GROUNDWATER NOVEMBER, 1998 D u P o n t W a s h in g to n Wort M a in P in n t Washington, West Virginia rw,v.. p= Section 3 000537 EID168102 M AH000474 Main Plant and Landfills Local Landfill 3.0 LOCAL LANDFILL Introduction.......................................................................................................................................................................... 3-2 Environmental Setting......................................................................................................................................................... 3-2 Water Quality.................................................................................................................................................................................................. 3-4 Site Conceptual M odel................................................................................................................................................................................... 3-5 Data Gaps................ ................................................................................................................................................................................... .. .3-6 References............................................................................................................................................................................. 3-6 Table 3.0 Table 3.1 A Table 3. IB Tables Local Landfill Monitoring Well Construction Data Local Landf))] Analytical Data Tables - Surface Water Local Landfill Analytical Data Tables - Groundwater Figure 3.0 Figure 3.1 Figure 3.2 Figure 3.3 Figure 3.4A Figure 3.4B Figure 3.5A Figure 3.5B Figure 3.5C Figure 3.5D Figure 3.5E Figure 3.5F Figure 3.5G Figure 3.6A Figure 3.6B Figure 3.6C Figure 3.6D Figures Local Landfill Location Map Local Landfill and Washington Works Main Plant 1-mile Radius Map Local Landfill Monitoring Well and Surface Water Sample Location Map Local Landfill Cross Section Location Map Local Landfill Cross Section A-A' Local Landfill Cross Section B-B' Local Landfill Groundwater Elevation Map - November 2001 Local Landfill Groundwater Elevation Map - December 2000 Local Landfill Groundwater Elevation Map - November 1999 Local Landfill Groundwater Elevation Map - November 1998 Local 1andfill Groundwater Elevation Map - November 1997 Local Landfill Groundwater Elevation Map - December 1996 Local Landfill Groundwater Elevation Map - December 1994 Local Landfill C-8 Concentration - May 2001 Local Landfill C-8 Concentration - May 2000 Local Landfill C-8 Concentration - May 1999 Local Landfill C-8 Concentration - May 1998 Compilation of history data Draft 2.doc Jan. 11. 02 Wilmington, DE 000538 3-1 EID168103 M AH000475 Main Plant and Landfills Local Landfill 3.1 Introduction The Local Landfill is located immediately adjacent to the main plant o ff the southern perimeter (Figure 3.0). The landfill and plant are located along the Ohio River in Washington, West Virginia, approximately seven miles southwest o f Parkersburg, West Virginia. A water use and well survey is currently being conducted for the area within a 1-mile radius o f the landfill perimeter (Figure 3.1). The Local Landfill consists o f three separate closed cells located on the heavily wooded 250-acre site. The cells were operated from 1964 to the middle 1980s under West Virginia/National Pollutant Discharge Elimination System (WVNPDES) Permit No. 0076538. The permit is currently undergoing renewal and is expected to be effective in January 2002. The permit requires monthly surface water sampling and semi-annual groundwater monitoring. Materials landfilled included scrap product, scrap metal, wood pallets and bins, and Powerhouse ash. Approximately 144 tons o f waste per year were disposed in the landfill. Powerhouse ash comprised about 70 percent o f the total waste. The specific source of C8 in historical groundwater and surface water samples collected from on-site locations has not yet been determined. The cells were closed and covered with approximately two feet o f low permeability soil. Figure 3.2 shows the location o f the three cells, monitoring wells, and surface water sampling points. The cells have no compacted or synthetic bottom liners. However, a hydrogeologic evaluation indicated that the natural soil present under the cell materials is composed o f reddish brown clay and weathered shale having a very low hydraulic conductivity o f about 5 X lO'7cm/sec (DuPont, 1990) and ranges from 3.5 to 19.5 feet in thickness. 3.2 Environmental Setting 3.2.1 Geology The Local Landfill is situated in a hilly area with relief o f approximately 30 to 40 feet. The slopes appear to be a combination o f natural topography with terraced outcrops o f massive sandstone and siltstone underlying varying amounts o f soil cover and man-made landfill plateaus. The locations o f two cross-sections developed for the Local Landfill are shown in Figure 3.3. The two cross-sections, A-A' and B-B', are shown in Figures 3.4A and 3.4B, respectively. A shallow tight clay layer starting at ground surface ranges from three to 25 feet thick. The clay contains some minor sandy and silty zones, and some pebbles and fragments o f sandstone in some locations. The clays are o f low plasticity and appear to be well compacted, often displaying a laminar structure (DuPont, 1990). Underlying the shallow clay layer is weathered shale ranging from 10 to 35. feet thick. Below this competent bedrock is present at depths ranging from 21 to 40 feet below ground surface. Compilation of history data Draft 2.doc Jan. 11,0 2 Wilmington, DE 000539 3-2 EID168104 M AH00047 6 Main Plant and Landfills Local Landfill The bedrock at the Local Landfill consists o f intcr-bedded red and varicolored sandy or calcareous shale, and gray, green, and brown sandstone o f the Permian age Dunkard Group. The maximum thickness o f the Dunkard Group in this region is 570 feet. The cross-sections show that the sandstone layers dip gently towards the north. Most o f the sandstone layers located in the upper portion o f the stratigraphic section are lenticular and laterally discontinuous. Two laterally continuous sandstone layers are located in the lower stratigraphic section. 3.2.2 Hydrology, Hydrogeology and Groundwater Flow Hydrology In general, infiltration o f precipitation is limited due to the very low hydraulic conductivity (5 x 10'7 cm/sec) o f the surficial clays (where these clays exist) and the weathered bedrock (DuPont, 1992). hi addition, infiltration o f precipitation into the cells is limited by approximately 2-feet o f low permeability soil and vegetative cover capping o f the cells. Leachate from the southern cell and the eastern cell flows from the seeps in the steep valley walls to leachate collection ponds, Pond 1 ,2 and 3 (Figure 3.2). Leachate from these ponds is discharged into a pipeline and conveyed to the main plant where it passes through storm water Outfall no. 001 into the Ohio River. Monitoring of combined pond effluent conveyed in the pipeline is conducted at Outlet 101. Hydrogeology Groundwater underlying the Local Landfill occurs in two zones. The discontinuous upper zone consists o f the clays and underlying weathered bedrock and has a very low hydraulic conductivity (DuPont, 1992). The lower zone consists o f the continuous and discontinuous sandstone layers having low permeability o f 1 x 10"5 cm/sec. The sandstone layers are separated by laterally continuous shale layers. Well yields from the sandstone layers are very low, ranging from <0.5 gpm to 1.5 gpm (DuPont, 1992). The upper (and thicker) o f the two laterally continuous sandstone layers located in the lower zone at elevations between 710-740 feet above Mean Sea Level (Figures 3.4A and 3.4B) has been designated as the "underlying significant aquifer" and is currently monitored semiannually as required by the permit. In 1989, eight monitoring wells were installed at the Local Landfill by Tetra Tech Richardson (LLMW-1 through 8). However, five o f these monitor wells (LLMW-1, -2, 3,-5. and -7 ) were closed in 1996 because they were screened in the discontinuous shallow clays and underlying weathered bedrock. LLMW-8, a bedrock well, was closed in 1997 because it was dry. Two additional bedrock wells, LLMW-9 and -10 were installed in 1995 and 1997, respectively. LLMW-9 was installed as a background well. These wells are screened within the significant underlying aquifer. Table 3.0 summarizes the well construction data for the existing monitoring wells. Groundwater Flow Groundwater elevations have been measured semiannually since 1994. Groundwater elevation contour maps for the significant underlying aquifer have been prepared from this data as required by the WVNPDES Permit No. 0076538. Figures 3.5A through 3.5G present maps for 2001 through 1996 and 1994. The groundwater contours were Compilation of history data Draft 2.doc Jan. 11. 02 Wilmington, DE 3-3 000540 EID168105 M AH000477 Main Plant and Landfills Local Landfill transferred from the original maps submitted for the permit to the updated Local Landfill base map. Evaluation o f limited groundwater elevation data for the closed wells (based on well installation information) indicates a downward vertical gradient between the upper discontinuous water bearing zone and the lower sandstone layers containing the underlying significant aquifer. In addition, C-8 present in the underlying significant aquifer provides further support for a downward vertical gradient. The groundwater contour maps for the underlying significant aquifer show that flow is from the south to the north towards the plant. The sandstones o f the underlying significant aquifer outcrop in the valley walls where discharge may occur as seeps. However, groundwater may also flow downslope within the fractured rocks o f the valley walls and ultimately enter the alluvial terrace deposit on the main plant. Groundwater discharging to seeps ultimately migrates to the plant through a number o f pathways. It can discharge downward to leachate collection ponds and pipes to the main plant where it enters storm sewers and discharges to the Ohio River. Groundwater also can seep to small streams draining the property to the north and flowing to the Quaternary alluvial terrace unconfined aquifer where pumping o f on-site active well fields controls groundwater flow. Groundwater flow in the alluvial aquifer, adjacent to the valley walls o f the Local Landfill, is towards the pumping wells located near and parallel to the Ohio River. The pumping o f these well fields also lowers the groundwater level to below river stage, inducing surface water from the river to flow into the alluvium towards the pumping wells. Water from the pumping wells is used for non-contact cooling purposes and ultimately is discharged to the Ohio River. 3.3 Water Quality 3.3.1 Surface Water Quality Table 3.1A presents the historical C-8 concentration data available for surface water. Figure 3.2 shows the surface water sampling locations, if the location currently exists. Samples from two outfalls, four outlets, two streams, and one leachate sampling location have been collected periodically since 1994. C-8 concentrations in the outfalls and outlets range from <0.2 ug/1 to 80 ug/1. Stream sample C-8 concentrations ranged from 4.12 ug/1 to 15 ug/1. The leachate sample, collected in the pipe from the leachate ponds, had a concentration o f 31 ug/1 (February 1994). For sample locations having more than two sampling events, the concentration o f C-8 is decreasing with time although it is difficult to accurately identify trends in samples with the limited data set. The C-8 concentration at Outlet 101, located at the northeastern portion o f the side, have decreased from 54 ug/1 to 12 ug/1 over the course of three sampling events. 3.3.2 Groundwater Quality Analysis o f C-8 in groundwater has been conducted annually on a voluntary basis since 1996. Table 3 .IB presents the data available for C-8 in Local Landfill monitoring wells. Groundwater was sampled annually in 1996, and 1998 through 2001 for three wells, LLMW-4, -6, and -9 . LLMW-10 was sampled twice in 1998 and 1999. The limited Compilation of history data Draft 2.doc Jan. 1 1 .0 2 Wilmington. DE 3-4 000541 EID168106 M AH000478 Main Plant and Landfills Local Landfill amount o f data makes it difficult to develop concentration contour maps. In addition, the monitoring wells are located at three separate areas (cells) o f the landfill; therefore, annual data for the past four years is posted in Figures 3.6A through 3.6D but is not contoured. C-8 concentrations in LLMW-9 and -10 range from non-detectable to 0.22 ug/1. The other two wells, LLMW-4 and -6, have the highest concentrations, ranging from 1.4 to 39 ug/1 and from 1.32 to 15 ug/1 respectively. Although there is limited data, the data shows a distinct reduction in C-8 concentration over time for wells LLMW-4, -6, and -9. 3.4 Site Conceptual Model The Local Landfill site conceptual model describes the potential exposure routes for current and future human and ecological receptors. Potential exposure routes were evaluated and classified as complete or incomplete. Access to the Local Landfill is restricted by electronic and locked gates at the road entrances. However, a posted nature trail has been established on the east side o f the landfill property. The trail loops around the eastern part o f the landfill starting and ending near the landfill's electrically operated gate. The nature trail is a marked trail and does not cross the cells. Access to the site from surrounding roads is possible but is discouraged due to the heavily wooded nature o f the property and the hilly terrain. The three cells at the Local Landfill are covered with a low permeability soil and vegetative cover. This cover prevents human and ecological receptors' exposure to the landfilled materials and to the soils potentially impacted by the landfill materials. However, these materials could potentially be exposed by extensive digging or rooting in the soil by animals or unauthorized people. Therefore this pathway is considered to be potentially complete but minimal. An additional potentially complete exposure pathway exists if the soil and vegetative cap is eroded by precipitation. Permit WV0076538 requires that the landfill surface will be inspected quarterly for evidence o f cracking or erosion (which could allow surface water to enter the solid waste deposit) and evidence o f settling o f solid waste (causing ponding o f surface water). Per Condition G-16 o f the permit, a stormwater erosion inspection is conducted annually. Therefore, this potentially complete pathway is considered to be minimal. At the landfill, precipitation is expected to take one o f two paths. It may infiltrate downward through the vegetated soil cover and into the cells. However, the low permeability o f the soil cover reduces the amount o f infiltration. If the precipitation infiltrates the soil cover, it will possibly encounter the landfill materials and will continue downwards. It may be prevented from further downward migration by the low permeability clays and weathered bedrock. However, if this water migrated farther downward, it should encounter the sandstones and shale layers. Groundwater flowing through the sandstone layers that outcrop in the valley walls located above the plant site's southern edge would be exposed at the surface in seeps, if seeps exist. The existence and location o f seeps at some places on the property have been observed, particularly those mentioned near the leachate collection ponds. Much o f the site remains unexplored, Compilation of history data Draft 2.doc Jan. 11, 02 Wilmington, DE ........................- 000541 3-5 EID168107 M AH000479 Main Plant and Landfills Local Landfill therefore, complete evaluation o f this potential exposure pathway (surface water to groundwater to surface water) is currently not available. Another possible migration route for precipitation is direct flow as surface water via overland flow downslope. In this case the water would not encounter the fill materials at any point it time. This potential exposure pathway is considered incomplete. Contact with groundwater impacted by C-8 is another potential exposure route for current and future human and ecological receptors. However, contact with groundwater under the landfill is limited, although, contact with leachate that has reached the ground surface via seeps is possible in the vicinity o f Pond 1, near the southern most cell. Ponds are open and accessible to limited number o f DuPont employees. As stated previously, groundwater flowing through the sandstone layers that outcrop in the valley walls located above the plant site's southern edge would be a possible contact location. However, because seeps in this area are not evident, it is likely that groundwater flows downslope within the fractured rocks o f the valley walls and discharges to the main plant alluvial terrace. Determining the existence and location o f seeps on the property has not been completed therefore, this potential exposure pathway cannot be fully evaluated. 3.5 Data Gaps The following data gaps were identified for the Local Landfill: Identify the locations o f seeps in the valley walls and determine water quality with respect to C-8 concentration. Determine the C-8 concentration in streams and other surface water bodies. Acquire additional geological data to refine the Site Conceptual Model. Install additional monitoring wells to provide additional groundwater flow data and groundwater quality data. Gather additional C-8 concentration data from monitoring wells for plume delineation. Activities to fill the data gaps will be proposed and discussed in the work plan. 3.6 References DuPont. 1990. Washington Works 1990 Preliminary Hydrogeologic Assessment. Solid Waste & Geological Engineering Department. ______ . 1992. Verification Investigation E.l. DuPont de Nemours Co. Washington Works April 1992. (Vol. 1). Compilation of history data Draft 2.doc Jan. 11, 02 Wilmington, DE 000543 3-6 EID168108- M AH000480 TABLES i 000544 EID168109 M AH000481 M AH000482 I a rf* 6ft m o o Table 3.0 Monitoring Well Construction Data Local Landfill Washington, WV Monitoring Wells L L M W -4 LLMW- 6 LLMW- 9 L L M W -110 Surface Elevation (feet) 844.7 793.2 788.54 805.94 Total Depth (feet) 155 90 80 87 Well Diameter (inches) 4 4 4 4 Slot Size (inches) 0.020 0.020 0.020 0.020 Screen Length (feet) 20 20 20 20 Elevation of Screen Interval (feet) 717.2-697.2 723.2-703.2 728.54-708.54 738.94-718.94 Table 3.1A Summary of Analytical Results: C-8 in Surface Water Samples Local Landfill Washington, WV | Sample LEACHATE OUTFALL 004 OUTFALL 005 OUTLET 001 OUTLET 002 OUTLET 003 OUTLET 101 STREAM 1 STREAM 2 Date 2/16/1994 9/27/2000 12/10/1999 6/3/1999 6/2/1998 5/29/1997 4/2/1996 2/16/1994 9/27/2000 12/10/1999 6/3/1999 6/2/1998 5/29/1997 4/2/1996 2/16/1994 5/29/1997 4/2/1996 5/29/1997 4/2/1996 5/29/1997 4/2/1996 9/14/2000 6/3/1999 6/2/1998 5/29/1997 4/2/1996 9/14/2000 12/29/1999 6/2/1996 4/2/1996 C-8(ug/l) 31 4.73 7.1 3.06 12 13 13 11 13.3 34 6.8 39 41 39 35 80 61 <0.2 72 23 20 12 15 54 11 7.2 4.12 10.7 15 14 000546 EID168111 M AH000483 Table 3.1B Summary of Analytical Results: C-8 In Groundwater Local Landfill Washington, WV Sample LLMW-4 LLMW-6 LLMW-9 LLMW-10 Date 5/16/2001 5/11/2000 5/19/1999 5/27/1998 4/11/1996 5/16/2001 5/10/2000 5/19/1999 5/27/1998 4/11/1996 5/16/2001 5/10/2000 5/20/1999 5/27/1998 4/11/1996 5/20/1999 5/28/1998 ____________ C -8 (uk/1)____________ 1.4 10 16.2 26 39 3 1.42 1.32 9 15 0.039 J <0.029 0.046 J <0.1 0.14 0.15 0.22 000547 EID168112 M AH000484 FIGURES 000548 ____ EID168113 M AH000485 M AH000486 P C T " TF ) |^ V :\ B l i 4 u (I4 . ..^;..i;.::;.; , , ' !'? ; { J ..... . - ; - , v2^<L-'J" ' s'^-700 r. ^ p s \VQ ,-. *' -' -,o , ` A Sofcs'at V \\ -Ede'rxZ^^ Cem T'**- '^ sm w Ww5OSn5K-rc^fL^C? - ^ 1Bi-JL Mil ,, S/-8 d fii'>v V 'v'uf p ! : ' j / ^ X.YI&.iV Z' :Y ^ jp;&m~<-u. i 1 . . . k % . \ i F / v f 'J '. > './6 , y-.-. ,\.^-:. / < 3 , / v //p fe ^ > ^ > , 2 ? ' -.iT: - > / / - K *< >s / A s ^ F , '&sj'W^l J/^~m./'/ 's '. -S r v \ ^ ! a ` -? > 7 ^ - ;<> '/ W . toVv..*:* -irt^ .r-r ^ \ y % ' -u *V, > 4 - 3 ^ 2- Tollmans! ~"7~a( --j. 1 * ^ 7 ' . * v(' -^ f i s ,y '\ <p l AA .K V W X L ,-.;. A -, ' >{' X '- ^ \ 7 \ $ A % ^ 4 ; hJ $ : ; R . ... ? ^ w 4 4 \ [ j, M --s -- ^***; -\ - , v /V- [i , ) i '- ^ . - J : M i0 & l -L h r y ^ * . '. -*' JP ` ^ ^ W ; -J` ; VK-. 4m`M: W/ : ?* /&U- V ' i m m ? - * ::^ jy < 1 --MILE RADIUS MAP 2400 SCALE 2400' Corporate Remediation Group A n A ttia n c e bet-ween DuPont a nd UPS D iam ond Barley Mill Plaza. Buiid^Q 27 W ilm ington, Oelowore 19805 Local Landfill W ash ing ton , W est V irg in ia SOU * j hcr. OWE i? /iS A n 0CS<N[D CMtCxtD PEL JPFBOVfO C W U U NO 7422AC03 neust 3 .1 000550 EID168115 M AH000487 m o 0o0> o> M AH000488 STATE ROAD #892 000552 M AH000489 C -------- OVtROUROCN MONITORING WELL -------- BEDROCK MONITORING WELL A. .A i s -------- LOCATIONS O F C R O S S - S E C T I O N S m o 03 09 -s| 400 C R O S S -S E C T IO N < n i> LO C A I IO N M AP PC. n, C o rp o ra te R e m e d ia tio n G roup XCtanc* Local Landfill Washington, West Virginia D ixfonl and URS Cia'nimd 400* 800' Scnty p io t o . ?T W m -nrslon. Delowore 19305 u r*m j | >00 j J 3 000553 I EID168118 M AH0004 90 M AH000491 m o coro> (O 000533 ]O o o> 03 roo MAH0004 92 M AH000493 rn O o CO Is) ----------------- -------------- 1 EID168122 00055? M A H 0004 94 M AH0004 95 m o o> 00 rcoo M AH0004 96 m o O00) hPo* M AH000497 m Q O) 00 9 9 9 tUol Cn 9i 9 M AH0004 98 m oe o0>0 o NO)) tn 9 DUPONT WASHINGTON WORKS PI.ANT e o o 9to m S o 09 NJ - I BEDROCK MONITOR WELL "j ,4 CONCENTRATION C-6 (ug/l) MAY, 2001 Corporate Remediation Group A lliance betw een D u P o n t o7v4 U P S D ia m o n d B o.'ley Mill PI0 7 0 , B u ilc in g 27 Wilmington, {Delaware 19905 C --8 IN G R O U N D W ATER MAY 2001 SCN.C As inaw n OAtC 12 /5 /0 1 Local Land fill W ash in g to n , WV 0CSCNC0 CHCOtO roi oa AAAICVlQ CAO f'H NO, 74J1A 09? ftCURt 3.6A M AH0004 99 M AH000500 M AH000501 M AH000502 000566 EID168131 M A H 000503 Section 4 Main Plant and Landfills Letart Landfill 4.0 LETART LANDFILL Introduction............................................... ..................................................................................................................................................... 4-2 Environmental Setting.................................................................................................................................................................................... 4-2 Water Quality.................................................................................................................................................................................................. 4-4 Site Conceptual M odel..................................... ............................................................................................................................................ 4-6 Data Gaps........................................................................................................................................................................................................ 4-7 References........................ 4-8 Table 4.0 Table 4.1 A Table 4. IB Tables Letart Landfill Monitoring Wells Construction Data Letart Landfill Analytical Data Tables - Surface Water Letart Landfill Analytical Data Tables - Groundwater Figure 4.0 Figure 4.1 Figure 4.2 Figure 4.3 Figure 4.4A Figure 4.4B Figure 4.5A Figure 4.5B Figure 4.5C Figure 4.5D Figure 4.5E Figure 4.5F Figure 4.6A Figure 4.6B Figure 4.GC Figure 4.6D Figures Letart Landfill Location Map Letart Landfill 1-milc Radius Map Letart Landfill Monitoring Well and Surface Water Sample Location Map Letart Landfill Cross Section Location Map Letart Landfill Cross Section A-A* Letart Landfill Cross Section B-B' Letart Landfill F-Zone Groundwater Elevation Map - November 2001 Letart Landfill F-Zone Groundwater Elevation Map - January 2001 Letart Landfill F-Zone Groundwater Elevation Map - October 1999 Letart Landfill F-Zone Groundwater Elevation Map - October 1998 Letart Landfill F-Zone Groundwater Elevation Map - December 1994 Letart Landfill F-Zone Groundwater Elevation Map - December 1992 I etart C-8 Concentration Map - July 2001 Letart C-8 Concentration Map - January 2000 Letart C-8 Concentration Map - July 1999 Letart C-8 Concentration Map - November 1991 Compilation of history data Draft 2.doc Jan. 1 1 ,0 2 Wilmington, DE 000567 4-1 E ID 1 6 8 1 3 2 M A H 000504 Main Plant and Landfills Letart Landfill 4.1 Introduction The Letart Landfill is located just north o f the town o f Letart in Mason County, West Virginia (Figure 4.0). A water use and well survey is being completed for the area within a 1-mile radius from the landfill perimeter (Figure 4.1). The landfill covers approximately 17-acres o f a 205-acre parcel o f land owned by DuPont Washington Works. It was in operation from the early 1960s to 1995. The landfill was operated and closed under West Virginia Solid Waste /National Pollutant Discharge Elimination System Permit No. WV 0076066. This permit requires quarterly groundwater monitoring, outfall and surface water monitoring and engineered cap maintenance. Figure 4.2 shows the landfill extent, orientation, topography, and monitoring well locations. The landfill was constructed within a natural ravine and has no compacted or synthetic bottom liners. However, a hydrogeologic evaluation indicated that the natural soil present under the landfill material is composed o f highly plastic clay and silt having a permeability o f about 10~7 cm/sec (DuPont, 1993). The soil thickness ranges from 4 to 14 feet, averaging about 8 feet in thickness. Letart Landfill received waste was from the Fluoropolymer manufacturing process at the plant that consisted primarily o f scrap product, scrap metal, wood pallets and bins, and miscellaneous trash. Approximately 5,000,000 pounds o f waste per year were disposed in the landfill. This waste is believed to be the source o f C-8 in the historical groundwater and surface water samples collected from on-site locations. The Letart Landfill was permanently closed by installing an engineered multi-layer geosynthetic and soil cap (DuPont, 2001). Included in the closure activities w'ere the installation o f a leachate collection system, erosion and drainage control measures and chain-link fencing. The cap construction was completed in April 2001. 4.2 Environmental Setting 4.2.1 Geology The Letart Landfill is situated on a heavily dissected plateau consisting o f several steep V-shaped valleys. Residual soil covers most landfill areas. In general, the soil at the site has been described as residual in nature, consisting primarily o f heavy clays derived from the weathering o f bedrock. At most landfill areas, the soil is less than ten feet thick, with a maximum thickness o f 20.5 feet. The underlying bedrock at the Letart Landfill consists o f inter-bedded red and varicolored sandy or calcareous shale, and gray, green, and brown sandstone o f the Permian age Dunkard Group. The maximum thickness o f the Dunkard Group in this region is 570 feet. The location o f two cross-sections, A-A' and B-B', crossing the landfill are shown in Figure 4.3. The two cross-sections o f the underlying geology are shown on Figures 4.4A and 4.4B. Compilation of history data Draft 2.doc Jan. 1 1 ,0 2 Wilmington. DE 000568 4 -2 E ID 1 6 8 1 3 3 M A H 000505 Main Plant and Landfills Letart Landfill Geologic investigations conducted at the Letart Landfill identified six stratigraphic water bearing zones that were designated as Zone A through Zone F, with Zone A being the shallowest zone and Zone F the deepest. These zones consist o f massive, very fine to fine grained crystalline sandstone with occasional shale lenses. Zones A through F are separated by locally continuous shale units'that are generally ten feet or greater in thickness. Zones A through D/E are discontinuous. Zone F is the first laterally continuous zone under the landfill. Zones A, C, D/E and F outcrop on the valley sides and along the Ohio River near the southern end o f the landfill. 4.2.2 Hydrology, Hydrogeology and Groundwater Flow Hydrology The Letart Landfill engineered cap system prevents surface water from contacting landfilled materials. Precipitation falling on the engineered cap system takes one o f two paths. It may infiltrate downward through the vegetated soil and encounter the impermeable geomembrane and then flow laterally downslope on top o f the geomembrane. Alternatively, precipitation may flow via overland flow on top o f the vegetative layer downslope. In either situation, this surface water does not contact the landfilled materials and migrates downslope towards drainage ditches constructed in or adjacent to the cap system. Precipitation falling on the northwest side o f the upper part of the cap flows downslope towards the southwest, away from the landfill, into a drainage ditch that flows to a sediment trap near LMW-6. Precipitation falling on the remaining portions o f the cap flow downslope and towards the south in drainage ditches. Hydrogeology Hydraulic conductivity testing [i.e., slug tests (Zone A) and borehole packer tests (Zones C, D/E and F)] o f the bedrock zones indicates that these zones display low hydraulic conductivity (Tetra Tech Richardson, 1990). Zone A hydraulic conductivity is low, ranging from 10"4 cm/sec to less than 10"5cm/sec. (There are no wells monitoring Zone B, therefore, it was not tested.) Zones C and F have very low hydraulic conductivities ranging from 10`6 cm/sec to less than 10`8cm/sec. Zone D/E hydraulic conductivities are also very low and range from 10'5 cm/sec to 10'8 cm/sec. Zone F has been designated the "underlying significant aquifer" as defined by to the West Virginia Solid Waste Management Regulations because it is laterally continuous under the landfill and is thought to be hydraulically connected to the Ohio River south o f the landfill. Most current groundwater monitoring is conducted in Zone F. The low hydraulic conductivity can be attributed to the very fine-grained nature o f the water-bearing units. In addition, many sandstone units in the region typically display effective porosity as low as 1 percent. This low porosity results from pore space being filled in by authigenic minerals (e.g. kaolinite) sometime after original sediment deposition. Zone F groundwater average linear velocities were calculated for flow from the north to the southwest and from the north to the southeast (DuPont, 2000). These values are relatively low, 0.01 and 0.003 ft/day respectively. The low velocities calculated in the F zone indicate that groundwater flow beneath the landfill is very slow, attributable to the Compilation ot history data Draft 2.doc Jan. 1 1 ,0 2 Wilmington, DE 000569 4 -3 EID168134 M A H 000506 Main Plant and Landfills Letart Landfill low hydraulic conductivity present in the F zone and all the overlying units as well. Low vertical hydraulic conductivities in the overlying shallow zones limit infiltration and recharge down to the F zone. The saturated thickness o f Zone F ranges from 22 feet in the upgradient well (LMW-2A) to between 2 and 8 feet in five downgradient wells (LMW-5A, -6, -9, -10, and -1 1 ). In many instances, the monitoring wells at the landfill cannot be sampled until 48 hours (or longer) after purging, when a sufficient quantity o f groundwater has recovered in the well screen interval. Groundwater Flow Thirteen monitoring wells have been installed at the Letart Landfill in the Zone A, C, D/E, and F sandstone units (Tetra Tech Richardson, 1989; 1990). Two o f these wells, LMW-10 and LMW-11, were installed in October 2001 to provide additional data from Zone F to the north and south o f the landfill. Table 4.0 lists the wells monitoring each zone and provides well construction information. Water level measurements and calculated groundwater elevations have been measured quarterly. Figures 4.5A through 4.5F provide available annual groundwater elevation contour maps for Zone F as required for the permit. This data was transferred from the original maps submitted for the permit to the updated Letart Landfill base map. The location and limited number o f monitoring wells within Zones A, C and D/E prevents determination o f groundwater flow directions within these zones. However, elevations measured in the monitoring wells indicate a downward vertical gradient within the site groundwater system. Within Zone F, a groundwater divide exists under the center o f the landfill in a north-south direction. Groundwater cast o f the divide flows southeast towards the Ohio River. Groundwater west o f the divide flows towards the west and southwest. Groundwater elevation data, including the newly installed LMW-11, the most northern monitoring well, indicates a slight component o f northward groundwater flow in Zone F in this area. Rapid decreases in the observed volume o f water discharging from the leachate collection system in 2001 indicate that groundwater flow under the landfill is being greatly reduced in response to the installation o f the engineered cap system. In addition, this reduction indicates that a new equilibrium state for groundwater flow has not yet been reached. Continued monitoring o f groundwater elevations o f Zones A through F is required to evaluate long-term changes in groundwater flow resulting from closure activities. 4.3 Water Quality 4.3.1 Surface Water Quality Voluntary surface water sampling for C-8 has been performed periodically since 1991. This data is presented in Table 4.1 A. The two locations sampled most frequently, the Upper and Lower ponds, no longer exist. During construction o f the engineered cap system, these ponds were de-watered and the sediments underlying the ponds were excavated and placed in low areas o f the landfill prior to the installation o f the cap. Currently, only two surface water locations still exist (due to landfill cap construction) Compilation of history data Draft 2.doc Jan. 11, 02 Wilmington, DE 4 -4 000570 E ID 1 6 8 1 3 5 M A H 000507 Main Plant and Landfills Letart Landfill and are being sampled. These locations include the leachate from the landfill [location 002(leachate basin)] and the stream located slightly east o f the property line along Rt. 33. The locations o f these surface water-sampling points are shown in Figure 4.2. 4.3.2 Groundwater Quality Groundwater from the monitoring wells has also been voluntarily sampled and analyzed for C-8 periodically since 1991. However, sampling did not take place on an annual basis until 1996 and quarterly sampling began the second half o f 1999, when C-8 was added to the permit as a monitoring parameter. Table 4. IB presents all historical analysis available for C-8 from monitoring wells at the Letart Landfill. The limited data set makes contouring the values difficult, therefore, the values were posted on maps and not contoured. Figures 4.6A through 4.6D present the C-8 concentration values for July 2001, January 2000, July 1999, and November 1991, respectively. An initial examination o f the groundwater data does not show any obvious overall concentration trends (Table 4 .IB). For wells having data from 1991 through 2001, it appears that the concentrations measured in 1991 were the lowest. From 1991, the concentrations in all wells increased. Currently, concentrations are now decreasing again in the most recent sampling events. However, identifying trends in the data is complicated by the fact that three different analytical laboratories have been contracted to perform the analyses between 1991 and 2001. In addition, the effects o f the installation o f the engineered cap system (preventing further surface water infiltration) may or may not be observable in the limited recent data. For the most recent sampling event and analysis (October 2001), the sampling and analytical procedures, and the analytical instrumentation used were modified to gain better accuracy in the C-8 analytical results. These modified procedures will be utilized for all future analysis o f groundwater samples for C-8. Continued monitoring o f C-8 concentrations in groundwater is required to accurately evaluate the long-term trends in groundwater quality. If it is assumed that impacted groundwater flows from Zone A downward to Zone F and ultimately migrates to the Ohio River, the C-8 historical mean for LMW-5B (Table 4.1B) can be used along with the estimated groundwater flux to calculate the C-8 loading to the river. The following assumptions were made in this calculation. The saturated thickness is 25 A at LMW-5B. This is higher than the most recent groundwater elevation measurement and therefore, is a conservative value. The length o f the aquifer discharging to the Ohio River is 1000 A based on the geologic cross-sections. O The historical mean value o f 855 ug/1 for LMW-5B, a downgradient well, represents the concentration o f C-8 in the aquifer. The velocity of groundwater in the aquifer is 0.01 ft/day. Groundwater average linear velocities for the F zone are calculated to be 0.01 A/day from the north to the southwest and 0.003 fi/day from the north to the southeast (DuPont, 2000). Using these assumptions, the calculation for loading to the Ohio River is shown below: Compilation of history data Draft 2.doc Jan. 11, 02 Wilmington, DE 00571 4-5 E ID 1 6 8 1 3 6 M A H 000508 Main Plant and Landfills Letart Landfill A = Area = 1000 ft length x 25 ft saturated thickness for Zone F = 25,000 ft2 V = Velocity = 0.01 ft/day (estimated) Q = flux = A x V = (25,000 ft2) x (0.01 ft/day) x (7.48 gal/ft3) x (365 day/yr.) = 682,550 gal/yr Mass = (855 ug/1) x (lg/109ug) x (lkg/lOOOg) x (1 Ib/2.205 kg) x (4.785 1/gal) = 1.47x1 O'9 lb/gal x 682,550 gal/yr = 1 x 1 0 Ib/yr Estimated annual loading to the Ohio River is very low based on the calculated mass and should result in a very low C-8 concentration in the Ohio River. The low calculated mass is reasonable given the low hydraulic conductivities and low average linear velocities observed in the F zone. 4.4 Site Conceptual Model The Letart Landfill site conceptual model describes the potential exposure routes for current and future human and ecological receptors. Potential exposure routes were evaluated and classified as complete or incomplete. The Letart Landfill closure was completed in April 2001 with the installation o f an engineered cap system. The engineered cap system prevents human and ecological contact with the landfilled materials. Contact with landfilled materials would only be possible if the cap system were to be intentionally breached by workers or trespassers or by extensive, vigorous digging by animals. However, dense vegetation and appropriately installed fencing restricts access by unauthorized individuals and animals. Therefore, direct exposure to landfilled materials is a potentially complete but very limited exposure pathway. Exposure o f landfilled material because o f erosion o f the engineered cap system due to storm runoff is also a potential human and ecological exposure pathway. However, cap system drainage controls were designed to convey the runoff from the landfill cap to a designated discharge point and to eliminate the potential for runoff-related erosion o f the cap. In addition, the landfill cap is required to be inspected at least quarterly (permit requirement C.12.A) for evidence o f erosion as part o f the site Storm Water Pollution Prevention Plan. Therefore, this potential exposure pathway is also a potentially complete but minimal exposure pathway. The Letart Landfill engineered cap system prevents surface water from contacting landfilled materials. Surface water migrates towards drainage ditches constructed in the cap system and is discharged at the southern edge o f the landfill. Because this surface water does not contact the landfilled materials, it is not impacted by C-8. Therefore, contact with this surface water is an incomplete exposure pathway. Groundwater contacting the landfilled material has been impacted by C-8. Contact with this impacted groundwater presents a possible human and ecological exposure pathway due to groundwater flow patterns. Groundwater flow under the landfill has shown that prior to the installation o f the engineered cap, surface water impinging on the landfill Compilation of history data Draft 2.doc Jan. 1 1 ,0 2 Wilmington, DE 4-6 000572 E ID 1 6 8 1 3 7 M A H 000509 Main Plant and Landfills Letart Landfill migrated downward through the landfill material. These waters continued to flow as groundwater downward towards Zone F where it then flowed laterally to the west and south. Currently, the engineered cap prevents surface water from contacting the landfilled materials although groundwater migrating laterally and vertically underneath the landfill may still contact the landfilled materials. Groundwater under the engineered cap migrates to the leachate collection system. Discharge from the leachate collection system is piped to an outfall [002(leachate basin)] where it enters a small, shallow, wet weather stream that flows approximately 400 feet before it discharges to the Ohio River. Contact with leachate is a potential pathway exposure route for current and future human and ecological receptors, however, this pathway is considered complete but limited due to the restricted access to the area. Zones D/E and F occur at elevations lower than the leachate collection system. Groundwater flowing from these zones to the south discharges to the Ohio River. Contact with this water is limited to the areas where these zones may outcrop on the valley walls. However, in general, groundwater flows downslope within the shallow soil, colluvium, and fractured rocks o f the valley walls and would only be exposed at the surface if seeps exist. Currently, there is no data available on the existence or location o f seeps on the slopes adjacent to the landfill or along the Ohio River. Therefore, evaluation o f this potential pathway exposure route for current and future human and ecological receptors is not possible at this time. Groundwater that flows to the west from Zone F is likely to discharge to nearby valley drainage systems and to ultimately migrate to the Ohio River. Again, groundwater flows downslope within the fractured rocks o f the valley walls and would only be exposed at the surface if seeps exist. Currently, there is no data available on the existence or location o f seeps in the valleys south o f the landfill. Therefore, evaluation o f this potential pathway exposure route for current and future human and ecological receptors is not possible at this time. 4.5 Data Gaps The following data gaps were identified for the Letart Landfill: Identify the locations o f seeps in the valley walls, particularly in the steep valley wall along the Ohio River, and determine water quality with respect to C-8 concentration. Determine the C-8 concentration in the Ohio River. O Determine the C-8 concentration in streams and other surface water bodies. O Acquire additional geological data to refine the Site Conceptual Model. O Install additional monitor wells to provide additional groundwater flow data and groundwater quality data. O Gather additional C-8 concentration data from monitoring wells for plume delineation. Activities to fill the data gaps will be proposed and discussed in the work plan. Compilation of history data Draft 2.doc Jan. 1 1 ,0 2 Wilmington, DE 000573 4 -7 E ID 1 6 8 1 3 8 M A H 000510 Main Plant and Landfills Letart Landfill 4.6 References DuPont. 1993. Letart Landfill Hydrogeologic Evaluation, July 1993. Corporate Remediation Group. ______ . 2000. Letart Landfill Groundwater Protection Plan SW/NPDES Permit No. WV0076066, January 7, 2000. Corporate Remediation Group. ______ . 2001. Certification Report Letart Landfill Cap Construction, June 2001. Corporate Remediation Group. Tetra Tech Richardson. 1989. Monitoring Well Installation Program, October 1989. ______ . 1990. Monitoring Well Installation Program at Letart Landfill - Summary Report, August 1990. Compilation of history data Draft 2.doc Jan. 11, 02 Wilmington, DE 000574 4 -8 E ID 1 6 8 1 3 9 M A H 000511 TABLES I 000575 EID168140 M A H 000512  Table 4.0 Monitoring Well Construction Data Letart Landfill Letart, WV Zone A C D F Monitoring Wells LMW- 1 LMW- 7 LMW- 8 LMW- 3 LMW- 3A LMW- 4 LMW- 5A LMW- 2A LMW- 5B LMW- 6 LMW- 9 LMW-110 LMW-111 Surface Elevation (feet) 766.53 770.24 777.06 673.1 672.61 649.17 645.23 778.53 644.39 754.22 774.85 732.37 774.34 Total Depth (feet) 33 35 38.5 30 60.1 28 28 180.8 72 183 225 189.85 161.5 Well Diameter (inches) 2 4 4 2 4 2 4 4 4 4 4 4 4 Slot Size (inches) 0.010 0.010 0.010 0.010 0.010 0.010 0,010 0.010 Screen Length (feet) 5 10 9 5 5 5 10 30 20 30 20 20 25 Elevation of Screen Interval (feet) 738.53-733.53 745.24-735.24 748.06-739.06 650.1-645.1 619.61-614.61 626.17-621.17 627.23-621.23 628.53-598.53 594.39-574.39 606.22-576.22 572.85-552.85 562.52-542.52 637.84-612.84 O 9 9 S3 m EID168141 Table 4.1A Summary of Analytical Results: C-8 in Surface Water Samples Letart Landfill Letart,WV Sample 002(LEACHATE BASIN) LEACHATE i LOWER POND N SPRING FLOW RT 33 STREAM STREAM MN RD SW SPRING FLOW UPPER POND Date 7/25/2000 4/3/2000 1/14/2000 10/21/1999 11/27/2001 7/20/01 7/25/2000 7/20/1999 1/14/2000 4/3/2000 10/21/1999 7/19/1999 5/28/1998 7/23/1997 4/17/1996 9/20/1994 3/15/1994 12/27/1991 11/22/1991 4/26/1991 3/22/1991 2/8/1991 1/18/1991 3/12/1992 3/12/1992 7/20/2001 7/31/2000 7/20/1999 7/23/1997 4/17/1996 3/15/1994 9/20/1994 3/12/1992 7/19/1999 5/28/1998 7/23/1997 4/17/1996 3/15/1994 12/27/1991 11/22/1991 4/26/1991 3/22/1991 2/8/1991 1/18/1991 C-*<ug/l) 1350 1900 920 3240 53.2 159 2250 1030 1410 1260 2530 1190 1100 1600 1900 2200 730 1300 1000 670 340 400 1200 0.3 0.3 2.01 0.573 2.23 2 1.8 0.5 0.9 1 517 480 <200 2100 4400 4100 790 930 500 2300 2900 000577 EID168142 M A H 000514 Table 4.1 B Summary of Analytical Results: C-8 in Groundwater Letart Landfill Letart, WV J =estimated value (below laboratory quantitation limit). Sample LMW-3A LMW-4 LMW-5A D /E-Zone W ells Date 7/19/1999 11/22/1991 3/22/1991 4/3/2000 1/14/2000 11/22/1991 3/28/1991 11/22/1991 3/22/1991 C-8 (ug/l) 60.3 350 380 272 172 830 690 0.8 1.6 000578 E ID 1 6 8 1 4 3 M A H 000515 Table 4.1 B Summary of Analytical Results (Con't): C-8 in Groundwater Letart Landfill Letart, WV Sample LMW-3 C -Zone W ells Dale 11/22/1991 3/22/1991 C-8 (uc/l) 1000 390 Sample LMW-1 Lfv/IW-7 LMW-8 A-Zone W ells Date 7/19/2001 1/31/2001 10/4/2000 7/24/2000 4/3/2000 1/13/2000 10/21/1999 7/20/1999 5/28/1998 7/23/1997 4/17/1996 11/22/1991 3/22/1991 7/20/2001 1/31/2001 10/4/2000 7/25/2000 4/3/2000 1/13/2000 10/20/1999 7/20/1999 5/28/1998 7/23/1997 4/17/1996 11/22/1991 7/19/2001 1/30/2001 10/4/2000 7/24/2000 4/3/2000 1/13/2000 10/20/1999 7/20/1999 5/28/1998 7/23/1997 4/17/1996 11/22/1991 I C-8 (uc/l) 6100 9190 10600 8990 13600 17400 12600 6920 24000 5100 1700 68 60 242 249 231 158 211 219 339 78.3 260 53 15 0.1 1120 2650 2300 2160 2180 2100 3260 1790 2700 2000 2200 280 000579 EID168144 M A H 000516 Table 4.1 B Summary of Analytical Results: C8 in Groundwater Letart Landfill Letart, WV J = estimated value (below laboratory quantitation limit). Sample LMW-3A LMW-4 LMW-5A D/E-Zone W ells Date 7/19/1999 11/22/1991 3/22/1991 4/3/2000 1/14/2000 11/22/1991 3/28/1991 11/22/1991 3/22/1991 C-8 (ug/l) 60.3 350 380 272 172 830 690 0.B 1.6 000580 E1D168145 M A H 000517 Table 4.1B Summary of Analytical Results (Con't): C-8 in Groundwater Letart Landfill Letart, WV Sample LMW-3 C -Zone W ells Date 11/2271991 3/22/1991 C-8 (UR/I) 1000 390 Sample LMW-1 L'MW-7 LMW-8 A -Z onc W ells Date 7/19/2001 1/31/2001 10/4/2000 7/24/2000 4/3/2000 1/13/2000 10/21/1999 7/20/1999 5/28/1998 7/23/1997 4/17/1996 11/22/1991 3/22/1991 7/20/2001 1/31/2001 10/4/2000 7/25/2000 4/3/2000 1/13/2000 10/20/1999 7/20/1999 5/28/1998 7/23/1997 4/17/1996 11/22/1991 7/19/2001 1/30/2001 10/4/2000 7/24/2000 4/3/2000 1/13/2000 10/20/1999 7/20/1999 5/28/1998 7/23/1997 4/17/1996 11/22/1991 C-8 (ug/l) 6100 9190 10600 8990 13600 17400 12600 6920 24000 5100 1700 68 60 242 249 231 158 211 219 339 78.3 260 53 15 0.1 1120 2650 2300 2160 2180 2100 3260 1790 2700 2000 2200 280 000581 _______ E ID 1 6 8 1 4 6 M A H 000518 FIGURES i 000582 EID168147 M A H 000519 2000 SCALE 2000' SOURCE! NEW HAVEN, V V-D H IO QUADRANGLE 7.5' SERIES SITE LOCATION MAP Corporate Remediation Group A n ranee b etw een DuPont a n d The I / - C D tam ond Croup -S o rte y Milt P Io jc . B u d d in g 2 ? W ilm ington, Delowore ISSSO -O O ?? L e ta rt Landfill S ite L etart, WV As stiDore r*u 2/21/9 0lSne TDL CMfCWEO AW*. DEL APPCOTO CADFllf NO. T25CA00J FCUW *0 000583 EID168148 M A H 000520 * 00055 EID168150 M A H 000522 ILSOfl; LMW-fi A ZOIC MONTOR WELL ^.L M W -3 C ZOHe MONTOR WELL 4. UIW-4 D A ZONE MONITOR WELL ^U*vMW-ZA f ZONE MOWTOR WELL CROSS SECT.ON TRACE Corporate Remediation Group An 4 lli n n M u r n D u fm i and lIKS D>in m 4 So' By 131 C;oo. Pu'ltfriQ J7 C t' n i<mo6 Letort Londifll Sit Letort, West Virginia ftfm "a fro 00058 EID168151 M A H 000523 A m orth j5 9 0 ~ MO -I 1 MO -j J 520 " | JSHQ sandstone AND _ SlUT STONE =0 .5?^ groundwater now Direction W tW M i'W af*W \\i*m wm ..n n rn tB aeolapl m 6 o o <P 9 00 in TO VT at trZSOOOHVW B WEST 780- B' EAST I - 780 760- 740- 720- 700- B80-- OFz= $ y 660- ui 640- ZONE C - 760 - 740 720 - 700 680 - 660 - 640 620600580- ZONE D /E ZONE F - 620 600 - 580 LEGEND 560- SANDST0NE AND SILTST0NE 2 - GROUNDWATER ELEVATION 1 1 /6 /0 1 = 0 GROUNDWATER a O W DIRECTION SHALE SCREENED INTERVAL NOTE: Surface soils are n o t shown os a se p a ra te geologic u n it. SCALE 100 200 FT 560 mm Corporate Remediation Group A n A lliance betw een D uP ont a n d U PS Diamond Borley Mill Ploro. Building 2 7 Wilmington, Delowo'e 198C5 C R O S S -S E C T IO N B - B ' L e ta rt L andfill Site L e ta rt, WV (M ( A irtOwO OWE 1 1 /7 /0 54*00 CmCC"C0 TDi U M oa ca nuc no. 7420A001 ncuw 4 .4 Q EID168153 i cr.rMn A.LMW -2A F ZONE MONITOR WELL 54 3.75 CROJNDWATOt QCVATTON UCASURCMENT 5 5 0 ---------- CRCONOWA'ER CONTOUR UNE Corporato Remedlation Group OuPoni UKS D iam tn* F ZONE GROJNDWATER ELEVATON CONTOUR MAP - NOVEMBER 2001 Letort Londiflt Site Leto ' i . West Virgnia m --J r l"'-* 000589 EID168154 M A H 000526 M A H 000528 M A H 000529 LEGEND: . LM W -B 570.48 5 6 0 ----- -= 3 ------------ F ZONE MONITOR W ELL GROUNDWATER ELEVATION DEC. 199A GROUNDWATER CONTOUR & ELEVATION GROUNDWATER FLOW ARROW <^> Corporate Remediation Group n Allianc botw em DuPont a n d Thu W-C D iam ond Croup B arley Mill P lo zo, O jild in g 2 7 W ilm ington, D d aw ore 1 9 8 8 0 -0 0 2 7 F ZONE GROUNDWATER ELEVATION CONTOUR MAP DECEMBER 1994 L e ta rt Land fill S ite L e ta rt, W est V irg in ia ICAU As sr*on MC 12/21/99 OCfcCM CmCCKC TOC ztc Xi *<fi OCL 7259AS07 000593 E ID 1 6 8 1 5 8 M A H 000530 & .L M W -B 57498 5 6 0 ------- -= a ------------ F ZONE MONITOR W EIL GROUNDWATER ELEVATION DEC. 1992 GROUNDWATER CONTOUR & ELEVATION GROUNDWATER FLOW ARROW Corporate Remediation Group 4 n Alliance between DuPont e n d The IV-C D iam ond Group B a rle y Mill P lo zo. B u ild in g ?7 W ilm ington. Delaware 1 9 8 8 0 -0 0 2 7 F ZONE GROUNDWATER ELEVATION CONTOUR MAP DECEMBER 1992 L e ta rt L an d fill S ite L e ta rt, W est V irg in ia SCM l A* oxrt 0 /2 1 /9 DCKNCO CNICMO TDL CAD FU NO. PEL 72S&A009 FCURC * 5F 000594 E ID 1 6 8 1 5 9 M A H 000531 J_fCtN t> L t / W - 8 A 20NE MONITOR WELL LM W -3 C ZONE MONITOR WELL L M W - 4 D /E ZONE MONITOR WELL - .L M W - 2 A r zone monitor well 2 4 2 C -S CONCENTRATION (ufl/t) Corporate Remediation Group 4n illune tatw ra DlJVnf entf C/RS (Ha**vnd UaJ Lelort LondiiU Site Letort. West Virginio I''"**0U. !"* W M 000595 EID168160 M A H 000532 000596 EID168161 M A H 000533 ww-to. s w\ LEGEND-. L M W -S A 20WC MONITOR WELL LM W -3 c zone monitor a L M W - 4 o /E ZCWE MONITOR WELL A - L M W - 2 A f zo n e monito well ^ 445 C -S CONCDTRATION (uq/l) Corporate RemecSatlon Group At. fluirtr fehiwtn Du/'cnt 1d URS diamond Is t o r i Landifl' Site Letort. West V irg ilio ***** on jCJfOT &c 000597 EID168162 M A H 000534 000598 EID168163 M A H 000535 M A H 000536 Section 5 e e <0 0<00 o iu i Main Plant and Landfills Hgbin Landfill 5.0 DRY RUN LANDFILL Introduction........................................................... ...... -- -- -- - ................________________5-2 Environmental Setting.............................................. ----------- ------------------ ---- ------------------------- ----------------------------------5-2 Water Quality........................................................ -- ................ .............................. ....................... .............................................. 5-4 Table 5.0 fable 5.1 A Table 5.IB Figure 5.0 Figure 5.1 Figure 5.2 Figure 5.3 Figure 5.4A Figure 5.4B Figure 5.5A Figure 5.5B Figure 5.5C Figure 5.5D Figure 5.5E Figure 5.6A Figure 5.6B Figure 5.6C Figure 5.6D Figure 5.6E Figure 5.6F Tables Dry Run Landfill Monitoring Wells Construction Data Dry Run Landfill Analytical DataTables - Surface Water Dry Run Landfill Analytical DataTables - Groundwater Figures Dry Run Landfill Location Map Dry Run Landfill l-mile Radius Map Dry Run Landfill Monitoring Well and Surface Water Sample Location Map Dry Run Landfill Cross Section Location Map Dry Run Landfill Cross Section A-A' Dry Run Landfill Cross Section B-B' Dry Run Landfill Groundwater Elevation Map - October 2001 Dry Run Landfill Groundwater Elevation Map - October 1999 Dry Run Landfill Groundwater Elevation Map - October 1998 Dry Run Landfill Groundwater Elevation Map - October 1993 Dry Run Landfill Groundwater Elevation Map - April 1992 Dry Run C-8 Concentration Map Bedrock Wells - July 2000 Dry Run C-8 Concentration Map Bedrock Wells - July 1999 Dry Run C-8 Concentration Map Bedrock Wells - July 1997 Dry Run C-8 Concentration Map Overburden Wells - July 2000 Dry Run C-8 Concentration Map Overburden Wells - July 1999 Dry Run C-8 Concentration Map Overburden Wells - May 1998 Compilation of history data Draft 2.doc Jan. 1 1 ,0 2 Wilmington, DE 000600 5-1 EID168165 M A H 000537 Main Plant and Landfills Dry Run Landfill 5.1 Introduction The Dry Run Landfill is located west o f the town o f Lubeck, in Wood County, West Virginia (Figure 5.0) and is about eight miles southwest o f the Washington Works main plant and the Local Landfill. A water use and well survey search is being completed for the area within a 1-mile radius from the Dry Run Landfill perimeter (Figure 5.1). The Dry Run Landfill covers approximately 17-acres o f a 535-acre parcel o f land owned by DuPont. The landfill began operation in 1986 and is still active at present. The landfill is operated under West Virginia Solid Waste /National Pollutant Discharge Elimination System Permit No.WV 0076244. This permit requires quarterly groundwater monitoring and monthly outfall surface water monitoring. Figure 5.2 shows the location o f the landfill, monitoring wells and surface water sampling points. The landfill was constructed within the drainage basin o f Dry Run, a tributary' o f the North Fork o f Lee Creek, which is a tributary o f the Ohio River. The Dry Run Landfill has no compacted or synthetic bottom liners. However, natural soil present under the landfill material is composed o f clay and weathered shale. The Dry Run Landfill receives waste from the main plant consisting o f non-hazardous waste including scrap product, scrap metal, wood pallets, fly ash and bins, and miscellaneous trash. Approximately 50,000,000 pounds o f waste per year have been disposed in the landfill. Currently, the C-8 source is believed to be the sludges from the closure o f the main plant anaerobic digestion ponds that were landfilled at Dry Run in 1988. The Dry Run Landfill remaining capacity calculations for 2001 show 4.4 years o f remaining life on the existing cell based on a 128,000 yd3/yr net fill volume consumption (DuPont 2000). 5.2 Environmental Setting 5.2.1 Geology The Dry Run Landfill is situated on a heavily dissected plateau consisting o f several steep V-shaped valleys. Residual soil covers most landfill areas. In general, the soil at the site has been described as residual in nature, consisting primarily o f heavy clays derived from the weathering o f shale. A geotechnical investigation for the Dry Run Landfill was completed by DuPont (1996). The investigation consisted o f advancing soil test borings, test pits, laboratory testing o f soil physical properties, stability analyses, and settlement analyses. DuPont (1996) determined that the natural residual soil underlying the landfilled materials consisted o f stiff to very hard silty clay and clayey silt with occasional rock fragments and a trace o f sand. The thickness o f this natural soil ranged from 12 to 28 feet in the test borings within the landfilled area. A 1989 monitoring well installation program, prepared by Tetra Tech Richardson Inc., indicated similar silty clay and weathered shale overburden. Four Compilation of history data Draft 2.doc Jan. 11. 02 Wilmington, DE 000*01 5 -2 E ID 1 S 8 1 6 6 M A H 000538 Main Plant and Landfills Dry Run Landfill overburden wells (DRMW 12A, 12B, 13A, 6A) were installed to depths ranging from 11 to 17 feet. The underlying bedrock at the Dry Run Landfill consists o f inter-bedded red and varicolored sandy or calcareous shale, and gray, green, and brown sandstone o f the Permian age Dunkard Group (Tetra Tech Richardson, 1989). The maximum thickness o f the Dunkard Group in this region is 570 feet. The location o f two cross-sections, A -A ' and B -B \ crossing the landfill and downgradient o f the landfill are shown in Figure 5.3. The two cross-sections are shown in Figures 5.4A and 5.4B. There are only a limited number o f deep monitoring wells around and upgradient from the landfill (DRMW-14). Dashed geologic contact lines were drawn on cross-section AA ' (Figure 5.4A) because there is not sufficient data to confidently extrapolate between DRMW-14, the upgradient well, and DRMW-13, the downgradient well. More geological data is available (DRMW-6, -11,-12, and -1 3 ) and was used in developing the downgradient cross-section, B-B' (Figure 5.4B) with more confidence. Cross-section BB ' supports the interpretations made in cross-section A -A ' o f rather flat lying stratigraphic units o f sandstone layers separated by shale layers. 5.2.2 Hydrology, Hydrogeology and Groundwater Flow Hydrology The Dry Run Landfill is situated on a heavily dissected plateau consisting o f several steep V-shapcd valleys. Dry Run drains the valley in which the landfill is located. Many small tributaries discharge from the nearby valleys into Dry Run before it joins up with the North Fork o f Lee Creek. Potesta & Associates, Inc. (1989) completed a hydrologic and hydraulic analysis o f the receiving stream below the Dry Run Landfill. They determined that the watershed soils are split between hydrologic soil groups (HSG) C and D and estimated the flow capacity at 481 cubic feet per second (that is greater than the 100-year 24-hour storm). Potesta (1989) also evaluated the 24-hour precipitation amount that would result in full flow conditions at the location where the capacity was estimated. Potesta determined that precipitation values between 5.25-5.99 inches in 24 hours would result in full flow. The installation o f a leachate collection system at the Dry Run Landfill encompassing the inactive lower half o f the landfill was completed by Potesta & Associates Inc. in 1999. Leachate from the landfill discharges into a leachate collection sump located northwest o f the landfill (Figure 5.2) through perforated pipes buried at the low edge o f the fill area. The leachate is pumped from the collection sump to a 50,000-gallon collection tank located at the top o f the hill. Leachate is pumped from the collection tank to a tanker truck, which is then hauled to the main plant for treatment in the site's wastewater treatment plant. Hydrogeology Groundwater is found in the overburden and the underlying bedrock aquifer. The bedrock aquifer is considered the underlying significant aquifer for NPDES permit required groundwater monitoring. A total o f 15 monitoring wells have been installed at Dry Run to monitor the overburden and bedrock aquifers. At this time, four overburden Compilation of history data Draft 2.doc Jan. 11. 02 Wilmington, DE 000602 5-3 E ID 1 6 8 1 6 7 M A H 000539 Main Plant and Landfills Dry Run Landfill wells (DRMW-6A, -12A, -12B, and 13A), and four bedrock wells (DRMW-12, -13, -14, and -1 5 ) still exist. The other seven wells were abandoned in 1999 by Potesta & Associates, Inc. as required by the permit because they were not being utilized for quarterly monitoring (Potesta, 1999). Table 5.0 provides the well construction data for existing monitoring wells. Groundwater Flow Water levels measured in November 2001 indicated overburden groundwater was encountered between 4 and 6 feet below ground surface. Although 3 o f the 4 wells completed in the overburden monitor the same hydrogeologic unit, well DRMW-6A is completed at a relatively higher zone, which is discontinuous at lower topographic areas. No groundwater flow maps were prepared for the shallow water encountered in the overburden section. _...................................... _ ............................... Annual groundwater elevation maps for the underlying significant aquifer were available for the years 1992-1994, and 1998-2001. These maps are presented in Figures 5.5A through 5.5G. The groundwater contours were transferred from the original maps submitted for the permit to the updated Dry Run Landfill base map. These maps show that groundwater in the bedrock aquifer flows from the southeast towards the northwest. The groundwater elevations measured for nested wells (DRMW-12, -12A, and 12B, and DRMW-13 and -13A ) are similar and the screened zones are constructed relatively close to each other, indicating that the overburden and bedrock aquifers may be in hydraulic communication downgradient of the landfill. 5.3 Water Quality 5.3.1 Surface Water Quality Historical surface water C-8 concentrations arc presented in Table 5.1 A for six sampling points. Sampling location for surface water sampling points still in existence can be found on Figure 5.2. Surface water samples have been collected periodically from these locations since 1996 and have been collected consistently for three locations (DRLeachate, Outlet 001 and at the property boundary) since 1998. The concentration o f C-8 in the leachate samples have been decreasing over time (from 62 ug/1 down to 27.4 ug/1) while concentration from the other locations are variable and do not indicate a clear trend (Table 5.1 A). 5.3.2 Groundwater Quality Historical groundwater sampling began in 1996. For wells that currently exist, sampling continues (DRMW-6 was abandoned in 1999; Potesta, 1999). C-8 concentration were contoured for some o f the sampling events for the overburden and bedrock wells. These concentration contours can be found in Figures 5.6A through 5.6 F. Data shown in Figure 5.6E was plotted but not contoured due to the data spread. The data for DRMW12-B and DRMW13-A for July 1999 appears anomalous compared to the other data for these two wells. The contour maps show that the highest concentration o f C-8 exists in monitoring wells 13 and 13A, bedrock and overburden wells, respectively. Compilation ot history data Draft 2.doc Jan. 11, 02 Wilmington. DE 000603 5 -4 E ID 1 6 8 1 6 8 M A H 000540 Main Plant and Landfills Dry Run Landfill These two wells are located downgradient from the central axis o f the landfill. For the majority o f the sampling events for most o f the other wells, both overburden and bedrock, the C-8 concentration has been less than 1 ug/1. The C-8 concentration for the 1999 sampling event in DRMW-14 was higher than other values measured for this well. Given that this well is an open bedrock well, and is relatively close to the landfill, this higher concentration may indicate communication o f surface or shallow aquifer waters through the open well, particularly because groundwater flow in the underlying significant bedrock aquifer flows from DRMW-14 north west toward the landfill area as opposed to groundwater flowing from the landfill toward the DRMW-14 well. 5.4 Site Conceptual Model The Dry Run site conceptual model describes the potential exposure routes for current and future ecological receptors. Potential exposure routes were evaluated and classified as complete or incomplete. Access to the Dry Run Landfill by is controlled by electronic gates on the major roads and locked gates on smaller roads. In addition, because the landfill is active, there is a crew o f workers on the landfill area during normal working hours. The daily activity discourages trespassers on the site. Therefore, direct contact with landfilled materials is a complete but minimal exposure route, limited to the workers in active portions o f the landfill. Direct contact with landfill materials in the inactive, lower half o f the landfill is incomplete due to the leachate collection system's geotextile and geomembrane cover. Contact with leachate at the landfill (or at the main plant where the leachate is treated) is considered a potentially complete but limited exposure route for the landfill and plant workers and samplers. Currently, the inactive lower half o f the landfill is covered by geotextiles and geomembranes o f the leachate collection system. Therefore, precipitation falling on this portion o f the landfill does not come in contact with the landfilled materials. This precipitation flows downslope via overland flow and discharges into storm water drainage ditches and eventually reaches Dry Run Creek. Therefore, this potential exposure route is considered incomplete. Precipitation falling in the upper half o f the landfill may also flow via overland flow down slope to the drainage ditches, again, an incomplete exposure route. Alternatively, this precipitation may infiltrate and come in contact with the landfilled materials as it migrates downgradient. However, this impacted water flowing within the landfill may be collected by the leachate collection system. If this impacted water migrates downward through the landfilled materials, it may eventually come in contact with the underlying shales and sandstone o f the bedrock and migrate downgradient within the bedrock aquifer. Contact with impacted groundwater is a potentially complete exposure route although currently, not enough hydrogeologic data exists to accurately evaluate this exposure pathway. Plans are underway for the expansion o f the leachate collection system and for a final cap/cover system. These activities in the future will further reduce precipitation infiltrating and contacting landfilled materials. Compilation of history data Draft 2.doc Jan. 11, 02 Wilmington. DE 000604 5-5 E ID 168169 M A H 000541 Main Plant and Landfills Dry Run Landfill 5.5 Data Gaps The following data gaps were identified for the Dry Run Landfill: Identify the locations o f seeps in the valley walls and determine water quality with respect to C-8 concentration. Determine the C-8 concentration in streams and other surface water bodies. Acquire additional geological data to more accurately develop the Site Conceptual Model. Install additional monitor wells to provide additional groundwater flow data and groundwater quality data. Gather additional C-8 concentration data from monitoring wells for plume delineation. Activities to fill the data gaps will be proposed and discussed in the work plan. 5.6 References DuPont. 1996. Report o f Geotechnical Investigation Dry Run Landfill, Washington Works Main Plant, Parkersburg, WV. Geotechnical Group, Civil Engineering Systems, DuPont Engineering. April 23,1996. ______ . 2000. 2000 Dry Run Landfill Operational Report. Submitted January 26, 2001. Potesta & Associates, Inc. 1989. Hydrologic and Hydraulic Analysis o f Dry Run, Area No. I. October 9, 1989. Letter from D. Mark Kiser to Dan Weber. ______ . 1999. Monitoring Wells MW-1, MW-1A, MW-4, MW-4A, MW-6, MW-10, MW10 Abandonment Report, Dry Run Landfill, DuPont Washington Works. March Tetra Tech Richardson. 1989. Monitoring Well Installation Program, October 1989. Compilation of history data Draft 2.doc Jan. 11. 02 Wilmington, DE 000605 5-6 E ID 1 6 8 1 7 0 M A H 000542 TABLES 000606 EID168171 H A H 000543 Table 5.0 Monitoring Well Construction Data Dry Run Landfill Lubeck, WV Monitoring Wells DRMW- 14 DRMW- 13 DRMW- 13A DRMW- 12 DRMW- 12A DRMW- 12B DRMW- 6A DRMW- 15 Surface Elevation (feet) 936.14 720.6 720.3 730.5 730.3 730.5 744.93 730.87 Total Depth (feet) 260 35 11 35 17 15 12.2 45 Well Diameter (inches) 10 4 4 4 4 4 2 2 Slot Size (inches) NA 0.010 0.010 0.010 0.010 0.010 0.010 Screen Length (feet) NA 15 5 15 5 10 Elevation of Screen Interval (feet) NA 700.6-685.6 714.3-709.3 710.5-695.5 718.3-713.3 725.5-715.5 20 705.87-685.87 M AH000544 O <T> m o oo>o to Table 5.1A Summary of Analytical Results: C-8 in Surface Water Samples Dry Run Landfill Lubeck, WV Sample DOWN STREAM DRLEACHATE OUTLET 001 PROPERTY BOUNDARY STREAM SAMPLING POINT#1 STREAM SAMPLING POINT#2 Date 4/9/1996 10/3/2000 12/29/1999 5/19/1998 7/22/1997 10/3/2000 12/29/1999 5/19/1998 4/9/1996 10/3/2000 4/9/1996 7/14/1998 12/29/1999 10/3/2000 12/29/1999 5/19/1998 10/3/2000 12/29/1999 5/19/1998 C-8 (u r /1) 25 27.4 34 56 62 31.5 66 17 86 10.3 9.9 0.88 39 0.758 0.54 1 27.6 87 4.6 000608 EID168173 M A H 000545 Table 5.1 B Summary of Analytical Results: C-8 in Groundwater Dry Run Landfill Lubeck; WV Sample DRMW-12 DRMW-12A | DRMW-12B i DRMW-13 DRMW-13A DRMW-14 DRMW-15 DRMW-6 DRMW-6A I>ate 7/19/2000 7/21/1999 5/26/1998 7/22/1997 4/10/1996 7/19/2000 7/21/1999 5/26/1998 7/22/1997 4/10/1996 7/20/2000 7/21/1999 6/16/1998 7/20/2000 7/21/1999 5/26/1998 7/22/1997 7/20/2000 7/21/1999 5/26/1998 7/22/1997 4/10/1996 4/10/1996 (dup) 7/20/2000 7/21/1999 6/16/1998 7/21/1997 4/10/1996 7/20/2000 7/21/1999 7/22/1997 4/10/1995 7/20/2000 7/21/1999 5/26/1998 7/22/1997 4/10/1996 J = estimated value (below laboratory quantitation limit). C-8 (ufi/1) 0.16 0.134 <0.10 <0.1 <0.1 0.128 0.081 J <0.10 <0.1 <0.1 ND (0.029) 5.4 <0.1 9.8 3.6 9.2 7 9.9 0.070 J 8.7 15 8.2 11 0.115 2.5 <0.1 <0.1 <0.1 0.763 0.263 1 0.97 0.212 0.096 0.27 0.36 0.19 000S03 EID168174 M A H 000546 FIGURES o o o s ia EID168175 M A H 000547 M AH000548 m ao04>0 o o o 0) o~>4 M A H 000549 5 5 E O T ---------------------------- oel checked tol \BPO0vC0t0CSC) APPR3VEC(CONST*UCTOS; mm Corporate Remediation Group A n A llia n ce betw een D u P o n t and U R S D ia m o n d B c r'e y Ml P la zo, 9 u ild n g 2 7 W ilm ington, Delawore 19805 MONITORING WELL AND SURFACE WATER SAMPLE LOCATION MAP Dry Run Landfill Lubeck, West Virginia VJ* Ae tfioafl ti*IT 1 2 /t /0 1 c m n a na 7422C004 nu^l 5.2 000613 EID168178 M A H 000550 000614 EID168179 M A H 000551 EID168180 FILL M A T E R IA L SILTY C L A Y S H A LE /W E A T H E R E D S H A L E SILT SANDSTONE SILTSTONE M ONITORING IN T E R V A L GROUNDWATER E L E V A T IO N (N o v . 2 0 0 1 ) GROUNDWATER F LO W D IR E C TIO N SECTION A - A ' 2.4-X VERTIC AL EXAGGERATION HORIZONTAL SCALE 160 0 150 VERTICAL SCALE 3 2 0 FT 66 66 122 FT O 9 K Cn C orporoie Rem ediotion Group An Liliane* 6*<vrn D'tPant and UfiS Dwnand Ror<lw M U PloO. 0uil<jirtg 77 W ii/ntnqloo, Os'awa'e 19805 C R O S S-SE C TIO N A - A ' Dry Run Londfill Lubeck, West Virginio NORTH B SOUTH B' ; r^50 LEGEND: S S S SILTY C L A Y E iiiii mra SH ALE /W EA TH E R E D S H A L E silt iW i I SANDSTONE SILTSTONE MONITORING IN T E R V A L ~S ~ <?= GROUNDWATER E L E V A T IO N (N o v . 2 0 0 1 ) GROUNDWATER FLO W D IR E C TIO N o 9 O 9> 9i SECTION B - B ' 2 .4 X VERTICAL EXAGGERATION H O RIZO NTAL SCALE 0 160 VFR TIC AL SCALE 32 0 FT 1 2 2 FT U ^..JOINS'*.) CROSS-SECTION B - B ' CoipofQte Remediation Croup Jn Astone ferfuevn vntf t/M diamond Boriey Mi pioto, Buii<J>nq 27 Wiimmoton. Oeioor* 19805 Dry Run Landfill Lubeck, West Virginia U I lavi ------- | lii M H | [ 5.4= EID168181 000617 EID168182 M A H 000554 M AH000555 mO oo oo ce 0to0 O) fe M A H 000556 e o m o o> o 9 o c*o 9  O O O) to o EID168185 M A H 000558 o m a o o O) oa 9> to 0O3) 000622 EID168187 M A H 000560 EID168189 0 0 0 6 25____ EID168190 3UW 12-A o.18 J ^ DRMW42-E3 ^ W 5.4 FILLAREA N257.500 000626 N 255,500 LEGEND OVERBURDEN MONITOR WELL 5.4 CONCENTRATION C - 8 ( u g / l) JULY, 1999 400 SCALE 400' N 2SC00 < M m t> <^> Corporate Remediation Group <4n A U ianci betu>eon D uPont and URS D iam ond B o ric y Will P lo zo, B u ild in g 27 W ilm ington, Celowore 19805 C - 8 IN GROUNDWATER OVERBURDEN WELLS, JULY, 1 9 9 9 D ry Run Land fill D u P o n t W ash ing ton W orks L u beck, W est Virginia SCM.C As thon QA1E I2/S/C1 DCiMU} CMtCKlO TOL MAW OCL CM ruS MO. n c -s.flc neuM 5.6G EID168191 N 256,500 N 256,000 e o N 255,500 o 9> K N 2S000 LEGEND C --8 IN GROUNDW ATER <gffPDW> < ^> OVERBURDEN WELLS. MAY, 1 99 8 OVERBURDEN MONITOR WELL m 8.7 CONCENTRATION C - B ( u g / l) M AY, 1 99 8 SCALE D Corporate Remediation Group AUianca betw een DuPont and U R S Diamond D ry R un L a n d fill D u P o n t W a s h in g to n W orks L u b e ck, W est V irg in ia 05 - 4 --------ESTIMATED LINE OF 00 ISOCONCENTRATION ( C - 8 ) 4Q Q CrOo 400' B o rle y Milt P iezo, B u iid in g 27 W ilm ington, Delaware 19B05 SCALI As shown CATE 12/5/01 CtSiCMtO chiocco TDL c<um OCL IfBftw in cad n a ho. n o -5 .cr Cu * 5.6F M A H 000564 000628 EID168193 M AH000565 Appendix 1 APPENDIX 1 CONSENT ORDER (ORDER NO. GWR-2001-019) 000629 EID168194 M AH000566 CONSENT ORDER ISSUED PURSUANT TO ARTICLES 5 and 12, CHAPTER 22 AND ARTICLE 1, CHAPTER 16 OF THE WEST VIRGINIA CODE. TO: E. I. DU PONT DE NEMOURS AND COMPANY DATE: November 14, 2001 W est Virginia Department of Environmental Protection Order No. GWR-2001-019 West Virginia Department of Health and Human Resources This CONSENT ORDER is issued by the Director o f the Division o f Water Resources and Director o f the Division o f Air Quality, West Virginia Department of Environmental Protection, and the Commissioner o f the Bureau for Public Health, West Virginia Department o f Health and Human Resources, pursuant to the authority set forth in more detail below. I. INTRODUCTION OF PARTIES. This Consent Order is entered into by and between the West Virginia Department o f Environmental Protection [WVDEP], the West Virginia Department o f Health and Human Resources - Bureau for Public Health [WVDHHR-BPH], and E. I. du Pont de Nemours and Company [DuPonl][collectively referred to as the "Parties"]. II. PURPOSE OF CONSENT ORDER. This Consent Order sets forth a series o f tasks to be performed by the Parties in order to determine whether there has been any impact on human health and the environment as a result o f releases o f ammonium perfluorooctanoate [C8], CAS Number 3825-26-1, to the environment from DuPont operations. C8 is a material used by DuPont in its fluoroproducts manufacturing process at its Washington Works facility located at Washington, Wood County, West Virginia. C8 is not identified as a hazardous substance, hazardous w'aste or otherwise specifically regulated under West Virginia or federal statute or regulation. This Consent Order has been negotiated in good faith and the actions undertaken by DuPont pursuant to this Consent Order do not constitute an admission o f any liability on its part. DuPont retains the right to controvert in any other proceedings, other than proceedings to implement or enforce this Consent Order, the validity o f the findings of fact and conclusions o f law set forth herein. DuPont agrees to comply with and be bound by the terms o f this Consent Order and further agrees in any proceeding to implement or enforce this Consent Order that it 1 006630 EID168195 M AH000567 will not contest the validity o f this Consent Order or the jurisdiction o f WVDEP and WVDHHRBPH to issue it. III. DEFINITIONS. Whenever the terms identified below are used in the Consent Order or in any exhibit or attachment hereto, the following definitions shall apply: 1. "The Agencies" shall mean the Department o f Health and Human Resources, Bureau for Public Health and the Department o f Environmental Protection, including the Divisions o f Air Quality and Water Resources. 2. "C8" shall mean the chemical compound ammonium perfluorooctanoate. 3. "Detection Limit" means the lowest analytical level that can be reliably achieved within specified limits o f precision and accuracy under routine laboratory conditions for a specified matrix. It is based on quantitation, precision and accuracy under normal operation o f a laboratory and the practical need in a compliance-monitoring program to have a sufficient number o f laboratories available to conduct the analyses. 4. Order. "Effective Date" shall mean the date set forth in Section XVII o f this Consent 5. "EPA" shall mean the United States Environmental Protection Agency. 6. "Force Majeure" shall mean conditions or circumstances beyond the reasonable control o f DuPont which could not have been overcome by due diligence and shall include, without limitation, acts o f God, action or inaction o f governmental agencies, or administrative or judicial tribunals or other third parties, or strikes or labor disputes (provided, however, DuPont shall not be required to concede to any labor demands), which prevent or delay DuPont from complying with the work plan. 7. "Groundwater Monitoring Well" shall mean any cased excavation or opening into the ground made by digging, boring, drilling, driving, jetting, or other methods for the purpose o f determining the physical, chemical, biological, or radiological properties o f groundwater. The term "monitoring well" includes piezometers and observation wells, which are installed for purposes other than those listed above, but does not include wells whose primary purpose is to provide a supply o f potable water. 8. "Groundwater Well" or "Well" shall mean any drilled or excavated groundwater collection system that supplies water for public, private, industrial, or agricultural use and shall include drinking water wells. As used in this Consent Order, this term applies only to wells 2 000631 EID168196 M AH000568 located in West Virginia. 9. "Reimbursable Costs" shall mean costs attributable (on an hourly basis) to the work o f Dee Ann Staats, Ph.D. in the negotiation and implementation o f this Consent Order, the costs attributable to any other participants on the C8 Assessment o f Toxicity Team, as described in Attachment C to this Consent Order, who are serving in that position as contractors to WVDEP, costs incurred by WVDEP in connection with the public meetings described in Attachment C, and costs attributable to any contractor retained at the direction o f the Groundwater Investigation Steering Team (GIST). 10. "Washington Works" shall mean the manufacturing facility owned by DuPont and located in Washington, Wood County, West Virginia, as depicted on Exhibit 1 to this Consent Order. 11. "The Facilities" shall mean the Washington Works and the Local Landfill, depicted on Exhibit 1, the Letart Landfill, depicted on Exhibit 2, and the Dry Run Landfill, depicted on Exhibit 3. 12. "Reference Dose" or "RfD" shall mean an estimate (with uncertainty spanning perhaps an order of magnitude or greater) o f a daily exposure level for the human population, including sensitive subpopulations, that is likely to be without an appreciable risk o f deleterious effects during a lifetime. Chronic RfDs are specifically developed to be protective for long-term exposure to a compound. 13. "Screening Level" shall mean the concentration in a specific media such as air, water, or soil, that is likely to be without an appreciable risk o f deleterious effects during a lifetime in the human population. IV. WAIVER OF RIGHTS. DuPont waives any and all rights it may have to appeal or challenge the validity or requirements o f this Consent Order, and shall not challenge the jurisdiction o f the Agencies to issue this Consent Order. This Consent Order applies to and is binding upon the Parties, and their successors and assigns. V. FINDINGS OF FACT. 1. C8 is a chemical substance which has no established state or federal effluent or emission standards. 2. C8 is a periluorinated surfactant manufactured by the 3M Company and others. 3 000632 EID168197 M AH000569 Since the early 1950's C8 has been used by DuPont in its fluoropolymer-related manufacturing processes at its Washington Works facility, located in Wood County, West Virginia. 3. Residues containing C8 from fluoropolymer manufacturing processes at Washington Works are or have been released to the air, discharged to the Ohio River, disposed o f at the Facilities, and otherwise shipped off-site for destruction and/or disposal. DuPont also captures for recycle a significant portion o f used C8. 4. No permits issued to DuPont authorizing releases o f pollutants to the environment contain specific limitations on the amount o f C8 that maybe released to the environment. However, C8 releases are addressed more generally in WVDEP Division o f Air Quality permits as particulate matter, PMio (particulate matter with an aerodynamic diameter less than or equal to 10 microns), or as a volatile organic compound. 5. Since as early as 1990, DuPont has performed regular, voluntary water sampling to detect the presence and level o f C8 in and around certain o f its Facilities in West Virginia and has reported the results o f this sampling to various government agencies. Currently, DuPont also samples and reports C8 concentrations in water as required by permits issued by WVDEP and EPA. 6. As a result o f DuPont's sampling, C8 has been detected in varying concentrations in and around certain of its Facilities in West Virginia, including private drinking water wells and public water supplies. 7. Analyses o f water samples have reported levels o f C8 in the Lubeck Public Service District ("LPSD") drinking water supply. 8. DuPont, by and through its use o f C8 in the fluoropolymer manufacturing process, is the likely source o f C8 presence in and around certain o f its Facilities in West Virginia. 9. Along with environmental sampling for C8, DuPont has performed and participated in multiple studies examining the potential effects of C8 exposure on human health and the environment. 10. Studies performed by DuPont and 3M have determined that C8 in sufficient doses, i.e., considering both amount and duration o f exposure, is toxic to animals through ingestion, inhalation and dermal contact. Studies have also found that C8 is persistent in humans and the environment. 11. Although DuPont has collected a large amount o f data on the presence o f C8 in the environment, the Agencies believe that additional information will assist them in delineating the extent and concentrations o f C8 in the environment at or near the Facilities. Available data collected by DuPont indicates that C8 is present in the surface and groundwater at the Letart and 4 000633 EID168198 M AH000570 Dry Run Landfills and at or near the Washington Works facility. 12. WVDEP and WVDHHR-BPH have determined that it is desirable to ascertain the source o f drinking water for persons potentially exposed to C8 in groundwater or surface waters in the area o f the Facilities. 13. EPA, WVDEP, and WVDHHR-BPH, in consultation and cooperation with one another, have requested, and DuPont has submitted, information and documents relating to the detection and presence o f C8 in and around the Facilities and documents with respect to the human health studies being performed related to C8 exposure. 14. Based upon information submitted by DuPont and reviewed to date by EPA, WVDEP, and WVDHHR-BPH, the Agencies believe that additional data would assist in their evaluation o f whether the ground and surface waters now containing C8 have a complete exposure pathway to humans and whether persons in and around the Facilities are at risk o f adverse health effects from C8 exposure. 15. There have been no independent govenunental or non-industrial studies performed on the human health effects o f C8 exposure for the purpose o f establishing an exposure standard for C8 applicable to the general public. 16. The Agencies have concluded that full site and health assessments are necessary to ascertain the extent and level o f C8 concentrations in the environment and to assist them in determining whether C8 presents any possible danger to the public. DuPont has agreed to participate and assist in this effort. 17. The fluoropolymers industry has committed to EPA to reduce total actual C8 emissions for either the year 1999 or the year 2000 by 50 percent within three to five years of each company's commitment date. DuPont committed to this goal in 2000. 18. DuPont installed, in March 2001, a filter and carbon treatment system at its Washington Works facility that is demonstrating removal efficiency o f 90-95% o f the C8 in its major C8-containing wastewater stream. VI. AUTHORITY TO ISSUE CONSENT ORDER. 1. The WVDEP is the state agency vested with the authority to protect the environment in West Virginia. 2. Article 12, Chapter 22 o f the West Virginia Code, the Groundwater Protection Act, grants to the WVDEP the authority to protect the State's groundwater from any contaminant 5 000634 _______ _________ EID168199 M AH000571 and, where contaminated groundwater is found, to institute a civil action or issue an order requiring that groundwater be remediated. 3. Article 5, Chapter 22 o f the West Virginia Code, the Air Pollution Control Act, grants to the WVDEP the authority to protect the State's air from pollutants and to institute a civil action or issue orders to enforce the statute. 4. The WVDHHR-BPH is the state agency vested with the authority to regulate and protect drinking water supplies in West Virginia. 5. Article 1, Chapter 16 o f the West Virginia Code, grants to the WVDHHR-BPH the authority to protect the public drinking water supply o f the state and to perform all investigation necessary to assure its purity and safety, and further grants to the WVDHHR-BPH the authority to institute actions and issue orders to restore the purity o f said water supply. VII. REQUIREMENTS OF CONSENT ORDER. The Agencies have concluded that it is o f great importance to have sufficient data upon which to determine the scope and potential risk o f the presence o f C8 in the environment in and around the Facilities. Therefore, the Agencies require the following: A. Establishment o f Groundwater Investigation Steering Team. 1. A "Groundwater Investigation Steering Team" (GIST) shall be established with members o f the team consisting o f WVDEP, WVDHHR-BPH, EPA Region ID, and DuPont. The WVDEP representative will be the team leader. The objectives and specific tasks o f the team are set forth in full in Attachment A o f this Consent Order. However, the primary purpose o f the GIST will be to oversee an expeditious, phased approach to fulfilling the majority o f the requirements set forth in Sections A through C. The work performed with oversight from the GIST shall be funded by DuPont in accordance with Section VIII o f this Consent Order. 2. Upon conclusion o f key milestones in the tasks set forth in Attachment A, the GIST shall issue interim or final reports setting forth findings o f fact and conclusions regarding background data, groundwater monitoring, and plume identification as described in Attachment A. Any groundwater monitoring plan developed pursuant to Attachment A shall survive the termination o f this Consent Order and shall be incorporated as a minor permit modification for the Facilities. DuPont reserves the right to request modification o f the plans upon renewal o f the Facilities' permits. B. National Pollutant Discharge Elimination System Requirements. 6 000635 E ID 1 6 8 2 0 0 M AH000572 1. Except as occasioned by no-flow conditions, DuPont shall perform monthly sampling for C8 at the Local Landfill at certain outfalls identified in West Virginia/National Pollutant Discharge Elimination System ("WV NPDES") Permit No. 0076538 as Outfalls 101, 004 and 005. 2. Except as occasioned by no-flow conditions, DuPont shall perform monthly sampling for C8 at the Washington Works facility at certain outfalls identified in WV NPDES Permit No. WV0001279 as Outfalls 001,002, 003, 005, 007, and 105. 3. Except as occasioned by no-flow conditions, DuPont shall perform monthly sampling for C8 at Dry Run Landfill at all outfalls identified in its WV NPDES Permit No. WV0076244. 4. Except as occasioned by no-flow conditions, DuPont shall perform monthly sampling for C8 at Letart Landfill at all outfalls identified in its WV NPDES Pennit No. WV0076066. 5. With respect to the requirements o f paragraphs VII.B. 1 through VII.B.4, all sampling shall be performed pursuant to established EPA guidelines, where applicable, and results shall be delivered to the WVDEP within thirty days o f receiving such results. DuPont shall record and report all attempts to sample under no-flow conditions. 6. Within 90 days o f the Effective Date o f this Consent Order, DuPont agrees to obtain a sample from each surface or alluvial water intake for public water supplies along the Ohio River in the area extending ten river miles downstream o f the Washington Works facility and one river mile upstream o f the Washington Works facility. If concentrations o f C8 above the Detection Limit are found in any sampled public water supply within the upstream or downstream segments initially sampled, the segments within which intakes are to be sampled shall be extended to twenty river miles downstream or two river miles upstream, as appropriate. If concentrations above the Detection Limit are found in any segment so extended, additional sampling will be performed on water intakes within thirty river miles downstream or three river miles upstream, as appropriate. 7. The additional monitoring requirements contained in this subsection shall be incorporated into the Facilities' West Virginia/National Pollutant Discharge Elimination System permits by minor modification. DuPont reserves the right to request a modification o f these requirements upon renewal o f the permits. C. Toxicological and Human Health Assessment. 1. DuPont agrees to fund the various tasks set forth below as a part o f this Consent Order by establishing an escrow account at a bank agreed to by the Parties, or by some other 7 000636 E ID 1 6 8 2 0 1 M AH000573 means agreed to by the Parties. Disbursements from said escrow shall be authorized by the C8 Toxicity Team Leader and DuPont representative jointly as described below. 2. A C8 Assessment o f Toxicity Team ("CAT Team") shall be established with members o f the team consisting o f representatives of: WVDEP WVDHHR-BPH EPA Region HI NICS ATSDR DuPont 3. The WVDEP representative shall be the Team Leader. 4. The individual team members, the tasks o f the team, and the team objectives are set forth in full in Attachment C o f this Consent Order. 5. Upon conclusion o f all the tasks set forth in Attachment C, the CAT Team shall issue a final report setting forth findings o f fact and conclusions as to what extent there may be health risks associated with C8 at the Facilities. D. Emission Modeling Assessment. 1. The following information shall be submitted to the Division o f Air Quality ("DAQ") within 30 days o f the Effective Date except where a different deadline is provided in this subsection: a. A complete and accurate list o f building dimension parameters for all structures located within the Washington Works facility that have a significant impact on the dispersion o f C8 emissions. Significant impact for each structure on the site shall be determined based on the "area o f building wake effects" as defined in the EPA User's Guide to the Building Profile Input Program (EPA-454/R-93-038 Revised Feb. 8, 1995). b. A complete and accurate list o f DuPont's current permitted allowable emission rates and confirmed actual C8 emission rates in pounds per year for the year 2000 for all sources located within the Washington Works facility. Each emission point shall be listed according to its stack I.D. and corresponding permit number. For each stack identified above as emitting C8 DuPont shall list all relevant stack parameters to be used in air dispersion modeling. c. shall be supplied: For each emission point (stack) emitting C8, the following information 8 000637 EID168202 M AH00057 4 1. Phase o f C8 (solid, vapor or aqueous solution) at stack conditions. ii. The particle characterization to be used for modeling including th particle size distribution (microns), the mass fraction o f C8 in each particle size category, and the particle density (g/cm3). iii. For particulate emissions, scavenging coefficients (hr/s-mm) for both liquid and frozen precipitation to be used for wet deposition modeling based upon the particle size distribution and the EPA's Industrial Source Complex, Version 3 Model Guidance (EPA-454/B-95-003b Sept. 1995) ("ISC Guidance"). DuPont may submit, within 30 days o f the Effective Date, information to support the use o f the normalized scavenging coefficient in the ISC Guidance (Figure 11 o f ISC Guidance) for C 8's scavenging coefficients. DAQ shall approve or disapprove with justification in writing, DuPont's submission. Should DAQ disapprove, DuPont shall have the right, within seven days, to request a meeting with DAQ and USEPA to address the deficiencies set forth in DAQ's letter and to request reconsideration o f DAQ's decision. Following a meeting o f the parties, DAQ shall issue a decision letter regarding C8's scavenging coefficients within seven days o f the meeting. DAQ reserves the right to require measurement o f C8's scavenging coefficients in its decision and DuPont reserves the right to assert a claim o f confidentiality in the event such a measurement is made. iv. For gaseous emissions, scavenging coefficients (hr/s-mm) for both liquid and frozen precipitation to be used for wet deposition modeling will be provided as a function o f droplet size using formulae in the open literature based on the physical properties o f C8 and consistent with Section 1.4 o f the ISC Guidance. DuPont may submit, within 30 days o f the Effective Date, information to support the proposed scavenging coefficient for gaseous emissions including information on the percentage o f C8 emissions that would be in gaseous form. DAQ shall approve or disapprove with justification in writing, DuPont's submission. Should DAQ disapprove, DuPont shall have the right, within seven days, to request a meeting with DAQ and USEPA to address the deficiencies set forth in DAQ's letter and to request reconsideration o f DAQ's decision. Following a meeting o f the parties, DAQ shall issue a decision letter regarding C8's scavenging coefficients within seven days o f the meeting. DAQ reserves the right to require measurement o f C8's scavenging coefficients in its decision and DuPont reserves the right to assert a claim o f confidentiality in the event such a measurement is made. d. To the extent that the phases exist, a solid, liquid and vapor phase (T-P) diagram for C8 with respect to pressure and temperature. The temperature and pressure ranges shall be representative o f exhaust gas conditions before and after control equipment. Estimates of C8's critical properties shall be provided along with measured ranges o f phase transition temperatures. 9 000631 EID168203 M AH000575 e. In lieu o f a binary phase (T-x-y) diagram representing the vapor-liquid equilibrium between water and C8, the solubility and Krafft Point o f C8 in aqueous solutions, measured pK value for C8 dissociation in aqueous solutions, and measurements o f C8 concentrations or related acids observed when tested in a head space GC at various concentrations, temperatures, and pHs representative o f the ranges observed during actual operating conditions. Furthermore a discussion regarding the volatility o f C8 in aqueous solutions as a function o f pH will be provided. The information in this paragraph shall be submitted to the DAQ within 60 days o f the Effective Date. f. Henry's law coefficient for C8 and a discussion o f its dependence on pH. The coefficient shall be defined at various temperatures covering the range observed during actual operations. g. Any carbon adsorption data in the form o f isotherms for C8 adsorption. DAQ will provide DuPont an opportunity to comment on modeling methodology and assumptions prior to finalizing the modeling results. 2. Any expenses incurred as a result o f accurately supplying the information requested above shall be covered by DuPont. 3. Upon submission o f the information required by this Subsection Vll.D, DAQ reserves the right to disapprove any data if the analytical methodology or quality control procedures arc deemed inappropriate. VIII. REIMBURSEMENT OF COSTS. 1. DuPont agrees to establish an escrow account to fund Reimbursable Costs under this Consent Order. Expenditures from this account shall be made upon joint approval by a duly designated representative o f the WVDEP and o f DuPont ("designated representatives"). Written notice o f such designation shall be sent to the persons identified pursuant to Section XVI o f this Consent Order. Prior to the execution o f this Consent Order, WVDEP has provided DuPont with an estimate o f Reimbursable Costs that WVDEP expects to incur under this Consent Order. 2. Within 10 business days o f the Effective Date, DuPont shall deposit in the escrow account funds in the amount o f fifty thousand dollars ($50,000). Each expenditure from the escrow account must be supported by an itemized accounting, including invoices and receipts. Said escrow account shall be replenished with additional funds whenever the balance is less than ten thousand dollars ($10,000), or as agreed to by the designated representatives. Any unexpended amount remaining in the escrow account at the conclusion o f the work to be performed under this Consent Order shall be returned to DuPont.3 3. DuPont's obligation to pay Reimbursable Costs under this Consent Order shall 10 000639 EID168204 M AH00057 6 not exceed two hundred and fifty thousand dollars ($250,000). Except as to Reimbursable Costs which are addressed separately in this section, all other costs incurred by DuPont in carrying out its obligations under Consent Order shall be the sole responsibility and obligation o f DuPont. IX. QUALITY ASSURANCE/QUALITY CONTROL. All sampling and analyses performed pursuant to this Consent Order shall conform to EPA guidance regarding quality assurance/quality control, data validation, and chain o f custody procedures. The laboratory performing the analyses shall be approved by the Parties prior to sampling. X. C8 REDUCTION PROGRAM. 1. Notwithstanding current permitted emission levels, DuPont agrees to limit overall C8 emissions to the air to no more than actual calendar year 2000 levels on a calendar year basis and shall further provide to the WVDEP monthly emissions reports regarding C8. The reporting requirement contained herein shall be modified to quarterly reports upon the issuance o f a Screening Level derived following the procedures set out in Attachment C. 2. DuPont agrees to reduce emissions to the air and discharges to the water o f C8 collectively by 50% from actual 1999 levels by December 31, 2003. 3. DuPont shall operate and maintain the filter and carbon bed treatment system at its Washington Works facility with the goal o f achieving 90-95% C8 removal efficiency in its major C8-containing wastewater stream. 4. dates: DuPont shall conduct the following construction projects and abide by the specified a. DuPont shall install an improved scrubber filter to replace recovery device T6IZC on permit R13-815D. Construction shall begin no later than February 28, 2002. Initial operation shall begin no later than the date o f start up after the April shutdown, or June 28, 2002, whichever is earlier. b. DuPont shall modify the stack for emission point T6IZCE so that the emission point elevation is 170 feet above grade. The stack diameter, velocity, and flow rate shall be sized to provide effective dispersion o f particulate emissions according to 45 Code o f State Rules, Series 20 (Good Engineering Practice as Applicable to Stack Heights). Construction shall begin no later than February 28, 2002. Initial operation shall begin no later than the date o f start up after the April shutdown, or June 28, 2002, whichever is earlier. At times when device T6IZC is not operating, permitted emissions from scrubber T6IFC shall be emitted to emission point 11 00064 ____________ E ID 1 6 8 2 0 5 M AH000577 T6IZCE. 5. DuPont shall conduct a scrubber optimization and recovery improvement program that shall consist o f a study o f scrubber operation for device C2DWC2 on permit R13-614A. The study shall be complete by the end o f March 2002. Provided the results are encouraging, the company shall implement identified improvements for this device and similar improvements for units C2DTC2 on permit R13-614A, C2EHC2 on permit R13-1953, and C1FSC2 on proposed permit for R13-2365A. Implementation o f the improvements for the latter devices will be complete no later than the end o f November 2002. XI. COMPLIANCE WITH SCREENING LEVELS. 1. The following requirements shall apply only if the procedures set out in Attachment C have been followed: a. No later than 60 days after receipt o f notification from the Agencies that data or information developed pursuant to this Consent Order or other information that is recent and valid demonstrates that DuPont's operations have resulted in C8 exposures above the Screening Levels derived following the procedures set out in Attachment C, DuPont shall submit a plan for review and approval by the Agencies that is designed to reduce such exposures to levels below the Screening Levels within a reasonable time (the "Remedial Plan" or "the Plan"). b. Within 30 days o f receipt o f the Remedial Plan submitted by DuPont, the WVDEP shall, upon consultation with the WVDHHR-BPH and based upon accuracy, quality, and completeness, either approve or disapprove the Plan. If the WVDEP disapproves the Remedial Plan, the WVDEP shall notify DuPont in writing that the Remedial Plan has been disapproved and shall specify the reasons for such disapproval. DuPont shall resubmit the Remedial Plan as revised to address the deficiencies identified in the notice. DuPont's failure to submit an approvable Remedial Plan shall be deemed a violation o f this Consent Order. 2. In the event EPA or the WVDEP develops and finalizes a reference dose/screcning level for C8 in accordance with applicable statutory and regulatory requirements ("the Regulatory EPA Standard") that would be applicable to Dupont's activities or the Facilities independent o f this Consent Order, DuPont's obligations under this Section shall be determined with reference to the Regulatory EPA Standard. DuPont reserves all rights it may have to comment upon, object to, or appeal the Regulatory EPA Standard in proceedings separate and apart from this Consent Order. XII. COMPLETION OF CONSENT ORDER. 1. Except as to DuPont's obligations under Section XI, this Consent Order and DuPont's obligations hereunder shall terminate upon issuance o f a completion letter(s) from the Secretary o f the WVDEP or his designee and from the Commissioner o f the WVDHHR-BPH to 12 000641 EID168206 M AH000578 DuPont. In a timely manner following receipt o f a written request from DuPont the respective Agencies shall issue the completion letter(s) to DuPont or shall issue a letter to DuPont detailing the obligations and work that have not been completed in accordance with this Consent Order. The Parties agree that the Agencies' obligation to issue this letter shall be deemed a non-discretionary duty. 2. DuPont's obligation to achieve and maintain compliance with the Screening Levels as provided in Section XI o f this Consent Order shall survive the termination o f this Consent Order. Such obligation shall terminate only as provided in Section XI or upon agreement o f the Parties. XIII. ADDITIONAL ACTIONS. The Agencies, individually or collectively, pursuant to their statutory duty and authority, may determine that additional action, beyond the tasks set forth in this Consent Order, is necessary to protect human health and/or the environment. Nothing in this Consent Order shall be construed as restraining or preventing the Agencies from taking such actions. Nothing in this Consent Order constitutes a satisfaction o f or release from any claim or cause o f action against DuPont for any liability it may have pursuant to the federal Clean Water Act, the federal Clean Air Act, the federal Safe Drinking Water Act, the West Virginia Groundwater Protection Act, the West Virginia Air Pollution Control Act, other statutes applicable to this matter, or West Virginia common law. Nothing in this Consent Order in any way constitutes a modification or waiver o f statutory requirements o f DuPont and nothing in this Consent Order shall obligate DuPont to undertake any actions not specified herein. XIV. ENFORCEMENT. Enforcement o f this Consent Order may be had by the filing o f a civil action by any o f the Agencies in the Circuit Court o f Wood County, West Virginia. Violation o f the terms and conditions o f this Consent Order by DuPont is a violation o f the West Virginia Code and may result in enforcement action being taken, including a request for civil penalties as set forth by law. DuPont shall not be liable for violations of this Consent Order due to any "Force Majeure" condition. XV. CONTENTS OF CONSENT ORDER/MODIFICATION. The entirety o f this Consent Order consists o f the terms and conditions set forth herein and in any attachments or exhibits referenced herein. Modification o f the terms and conditions o f this Consent Order including any modification o f timeframes or deadlines established in this Consent Order shall be made only by agreement o f the Parties in writing, except that modifications to any 13 000642 _________ EID168207 M AH00057 9 requirement set out in the attachments to this Consent Order may be made upon consensus o f the members o f the GIST or the CAT Team, as appropriate. XVI. ADDRESSES FOR ALL CORRESPONDENCE All documents, including reports, approvals, notifications, disapprovals, and other correspondence, to be submitted under this Consent Order shall be sent by certified mail, return receipt requested, hand delivery, overnight mail or by courier service to the following addresses or to such addresses DuPont or WVDEP may designate in writing. Documents to be submitted to WVDEP should be sent to: WV Department o f Environmental Protection 1356 Hansford Street Charleston, West Virginia 25301 Attention: Armando Benincasa, Esq. Attention: Dee Ann Staats, Ph.D. Phone No.: (304) 558-2508 Documents to be submitted to WVDHHR-BPH should be sent to: WV Department o f Health and Human Resources Bureau for Public Health 815 Quarrier Street, Suite 418 Charleston, West Virginia 25301 Attention: William Toomey, Manager o f Source Water Assessment Program Phone No.: (304) 558-2981 Documents to be submitted to DuPont should be sent to: E. I. du Pont de Nemours and Company Washington Works P.O. Box 1217 Parkersburg, West Virginia 26102 Attention: Paul Bossert Phone No.: (304) 863-4305 and 14 0Q0643 EID168208 M AH000580 E. I. du Pont de Nemours and Company Legal Department, Suite D-71 1007 Market Street Wilmington, Delaware 19898 Attention: Bernard J. Reilly, Esq. Phone No.: (302)774-5445 XVII. AUTHORIZED SIGNATORIES/NON-ADMISSION. The undersigned representatives state that they have had full and fair opportunity to review this Consent Order and have had opportunity to allow for their counsel to do the same, and therefore enter this Consent Order freely and with full knowledge o f its terms and conditions. The undersigned do hereby confirm that they have the authority to enter into this Consent Order and have the authority to bind their respective party. Neither the terms o f this Consent Order, nor execution thereof shall constitute an admission by DuPont o f any fact or o f any legal liability. DuPont expressly reserves all rights and defenses that may be available in any proceeding involving third parties or involving WVDEP and WVDHHR-BPH in any other matter. This Consent Order may be signed in counterparts and shall be effective upon signature o f all the Parties below ("Effective Date"). Entered th is_____ day o f ___________ , 2001, by: WEST VIRGINIA DEPARTMENT OF ENVIRONMENTAL PROTECTION BY: WILLIAM E. ADAMS, DEPUTY SECRETARY West Virginia Department o f Environmental Protection 1356 Hansford Street Charleston, West Virginia 25301 Entered this_____ day o f ___________ , 2001, by: 15 000641 EID168209 M AH000581 WEST VIRGINIA DIVISION OF HEALTH AND HUMAN RESOURCES - BUREAU FOR PUBLIC HEALTH BY: DR. HENRY TAYLOR, COMMISSIONER Bureau for Public Health West Virginia Department o f Health and Human Resources Diamond Building, Room 702 350 Capitol Street Charleston, West Virginia 25301 Entered th is_____ day o f ___________ , 2001, by: E. I. DU PONT DE NEMOURS AND COMPANY BY: PAUL BOSSERT, PLANT MANAGER 16 000645 EID168210 M A JH 000582 Attachment A C8 GROUNDWATER INVESTIGATION STEERING TEAM A team o f scientists shall be assembled to assess the presence and extent o f C8 in drinking water, groundwater and surface water at and around the DuPont Washington Works facility, and the Local, Letart, and Dry Run Landfills. The Groundwater Investigation Steering Team (GIST) shall include scientists from WVDEP, WVDHHRBPH, EPA Region III, and DuPont. DuPont shall fund the GIST via an escrow account as provided in Section VIII o f the attached Consent Order ("the Consent Order"). Disbursements from this account shall be authorized jointly by the WVDEP GIST leader, and the DuPont representative, Andrew S. Hartten. A schedule summarizing key GIST tasks, submittals, start and end dates is provided at the end o f this document. GIST Member Organizations/Represcntatives/Gencral Functions WVDEP David Watkins -Groundwater Protection- GIST team leader; escrow funds disbursement oversight; project management and coordination George Dasher-advisor and technical review Dee Ann Staats, Ph.D.-advisor EPA Region III Garth Connor-science advisor Jack C. Hwang - Hydrogeologist Roger Rheinhart-Environmental Engineer DuPont Andrew Hartten-Principal Project Leader/HydrogeoIogist-technical review, project management and coordination o f field investigation activities; escrow funds disbursement oversight. WVDHHR-BPH William Toomey-Manager, Source Water Assessment Program- Bureau for Public Health advisor 00064 EID168211 M AH000583 GIST Team Objectives and Efforts The primary objective o f the GIST is to efficiently review and direct groundwater and surface water monitoring and investigation activities as prescribed in the Consent Order and in this Attachment. The GIST will utilize a phased approach and employ rapid team decision making toward meeting the requirements in an efficient and timely manner. Unless otherwise directed by the GIST, the tasks outlined below shall be performed by DuPont or its representatives. The GIST will issue a final report(s) with findings and conclusions regarding groundwater quality in and around the Facilities, and the extent o f groundwater contamination in and around the Facilities. The GIST final report shall further make recommendations regarding the need for any further work or actions that need to be taken to assure protection o f groundwater quality and human health into the future. The tasks set forth below and in the Consent Order are the minimum tasks to be performed by DuPont and the GIST pursuant to the Consent Order. Additional tasks may be necessary to assure the goals [full groundwater assessment and C8 impact, plume identification, and receptor identification] o f the GIST and the Consent Order are met. Those tasks shall be agreed upon by the GIST. Key Tasks of GIST Task A: Groundwater Use and Well Survey/Groundwater Monitoring Objectives: Conduct a distance-phased groundwater well and water use survey within a 1-mile (and possibly 2 and 3-mile) radial distance or directionally focused distance o f the Washington Works and Local, Letart, and Dry Run Landfills.1 Summary: The phased approach to the water and groundwater well use survey will allow the GIST to focus efforts along established C8 impact transport pathways and cease activities in directions where impacts are not present or where there are minimal concentrations. Data results tables will be generated in a timely manner to allow the GIST to meet, evaluate the data, and determine the next course o f action. The GIST will determine when the final groundwater well use survey shall be released. DuPont agrees to perform, under the supervision o f the GIST and through an agreed-to third party, a groundwater use and well survey identifying and sampling all groundwater wells within a 1-mile radius o f the three landfills set forth above and the Washington Works facility. The phased approach may be amended by the GIST should field conditions require, e.g., lack of sampling wells in the 1-mile radius, lack o f quality sampling points within the 1-mile radius. Sampling shall be performed with the specific purpose o f finding and measuring the C8 concentration in water. Should concentrations o f C8 found in groundwater wells exceed 1 pg/1 within the 1-mile radius, the GIST will determine 1 The water use survey should be in substantially the same format as Attachment B. A2 (MMM547 ___________ ______ E ID 1 6 8 2 1 2 M AH000584 whether to expand the well survey to a 2-mile radius, a 3-mile radius, or in a specific direction only. Drinking water wells that measure above 1 pg/1 shall be re-sampled at a frequency to be determined by the GIST. Mote: The level o f 1 ug/1 is utilized in this Consent Order for monitoring purposes only and not as a benchmark for determining risk and this level may be adjusted as determined the GIST in furtherance o f the tasks and objectives set forth in this Attachment. Timing: The initial well survey within a 1-mile radius o f the Facilities will be conducted within 60 days o f the Consent Order's Effective Date. Additional well survey activities will be conducted on a schedule to be determined by the GIST. Task B: Assessment of Existing_Groundwater and Surface Water Monitoring Data Objectives: Develop and implement a monitoring plan that determines the presence and extent o f C8 in drinking water, groundwater, and surface water in and around the Washington Works facility and Local, Letart, and Dry Run Landfills and provide a compilation o f all available groundwater/surface water monitoring and hydrogeologic characterization data for each facility, as reflected in Table A -l. Summary: The GIST will be tasked with an expedited evaluation of existing historical data and hydrogeologic information in order to prioritize the initial scope o f work for continuing groundwater monitoring and any additional investigation activities (e.g., monitoring well installations) required under plume identification. DuPont shall provide all historical data and hydrogeologic information it may have related to the Facilities. Timing: Within 30 days o f the completion o f Task A, the GIST will review all the C8 analytical and facility hydrogeologic information to determine the scope o f work for groundwater monitoring and additional investigation. The GIST will then establish a schedule for those activities. It is anticipated that a summary o f all historical information for each facility will be submitted to GIST within 60 days o f the Consent Order's effective date. Task C: Plume Identification/Groundwater Assessment Objective: Determine the vertical and horizontal extent o f any and all C8 impacted groundwater exceeding 1 ug/1 or as directed by the GIST, which may determine a lower threshold than 1 ug/1. This task shall also include an assessment o f C8 impacted groundwater at Letart Landfill and its impact on the Ohio River and public water supplies along the river. Summary: The GIST shall first review historical data and results o f Task A to determine an appropriate scope o f work. Activities should be prioritized to address groundwater plumes contributing to or with the potential to flow toward off-site receptors, with emphasis on those areas where groundwater is used as a drinking water source. 000648 EID168213 M AH000585 Upon completion o f investigation activities, DuPont shall provide the GIST with predicted groundwater flow and contaminant transport models to assess future plume migration. Timing: Upon review o f all available information and on a schedule to be determined by the GIST, the GIST will complete an initial evaluation o f data to determine and prioritize plume identification. The timing o f the initial phase o f plume identification/investigation activities and other activities will be on a schedule established by the GIST. Further investigatory activities needed and agreed to by the GIST to carry out the goals o f the GIST shall be performed by DuPont on a schedule established by the GIST. Modeling Any and all modeling performed pursuant to this attachment and the Consent Order shall use Groundwater Modeling System, or some other model as approved by the GIST. 000649 EID168214 M AH000586 TABLE A-l ^ ^ f ^ ^ ^ W Q N ^ m S T b t a c ^ ^ 4 J ^ M ' M O N I T O I ^ G L A N ' a. Dependent upon the availability o f certain information, an historical data summary documented in a report that includes: b. A groundwater monitoring plan for the Facilities which should address, at a minimum: A location map. A site map showing the location o f all known groundwater monitoring wells, residential groundwater wells and public water supply within a 1-mile radius the Facilities. Top-of-groundwater maps. These should span the entire sampling life o f the site and should be no less than yearly. If DuPont has only one year's worth o f data for a given site, then these maps should be for each quarter; if DuPont has several years worth o f data for each site, then these maps can be annual. C8 concentration contour maps. These should span the entire sampling life o f the site and should be no less than yearly. If DuPont has only one year's worth o f data for a given site, then these maps should be for each quarter; if DuPont has several years worth o f data for each site, then these maps can be annual. All the C8 groundwater data that has been collected to date. These data should be submitted in easy-to-read tables. These tables should use the method, "<x", to designate all concentrations below the laboratory's minimum detection limit (not "ND" or some other abbreviation), and they should use "mg/" or "pg/" as the unit designation. If unable to provide the above data, DuPont shall document the reasons why it is unable to gather and submit the information. C8 sampling. The samples should be taken from all the wells at the three landfill sites and from a select number o f wells at the Washington Works plant. These select wells are to be chosen by the GIST before the groundwater monitoring program begins based on evaluation o f historical data/information. The frequency o f sampling shall be monthly for the first four months following the Effective Date and quarterly thereafter. Any new wells required for monitoring or plume identification purposes will be integrated in each site's groundwater monitoring program on a schedule agreed to by the GIST. 000658 E ID 1 6 8 2 1 5 M AH000587  Report o f Results. Reporting should be quarterly and to the WVDEP Groundwater Program at the following address. WVDEP Division o f Water Resources Groundwater Program 1201 Greenbrier Street Charleston, West Virginia 25311 Re: DuPont/C8 monitoring. Each report should include the following: (a) A site location map. (b) A site map showing the groundwater monitoring well locations. (c) A top-of-groundwater map. (d) A C8 concentration map. (e) Groundwater elevation and well screen data. (f) A table o f all the historical C8 sampling data. Note: where available information allows, abbreviations should not be used to designate No Detect concentrations and the units "ppb" and "ppm" should not be used. (g) Laboratory analysis sheets. (h) Chain o f custody records. A -6 ___ 00065! ____ __________ E1D168216 M AH000588 Attachment B Name: Address: GROUNDWATER WELL USE SURVEY Phone: ________________________________ Best Time to Contact Owner:__________________ 1. Do you have one or more water well(s) on this property? (It need not be in use currently.) If no, stop now and return survey. Yes _____ No _____ County Water Well Permit No. _________________________ 2. Is the well(s) currently (circle one) used unused or filled in? 3. Is the well(s) used for drinking water? Yes _____ No _____ 4. Is this well(s) used for other purposes? If yes, please specify uses below: 5. What is the approximate frequency o f use? Circle One: Daily Weekly Monthly Summer 6. Date last used? ______________________________ 7. Is there a pump in the well? Yes _____ No _____ 8. Is there a conditioner, softener, chlorinator, filter, or other form o f treatment for the system? Yes _____ No _____ If so, what is the form o f treatment? _______________________ B i 000652 EID168217 M AH000589 9 . Is there any faucet where water does not first pass through the treatment system? Yes _____ No _____ If yes, is it (circle one) inside or outside? 10. What year was the well constructed? ____________ 11. Please provide the following information regarding the well(s) if known: (circle one) A. Total Depth (feet below ground surface): 30-60 60-90 90-120 120 or more B. Casing Type: PVC steel stone none o th er________________ C. Well Construction: dug drilled open or uncased bedrock D. Screened Interval (length in feet): 0-10 10-20 20-30 30-60 60 or more E. Well Diameter (inches): 0-6 6-12 12-24 24 or more B-2 000&&3 EID168218 _ M AH000590 Attachment C C8 ASSESSMENT OF TOXICITY TEAM A team o f scientists shall be assembled to assess the toxicity and risk to human health and the environment associated with exposure to ammonium perfluorooctanoate (C8) releases from DuPont's activities. The C8 Assessment o f Toxicity Team (CAT Team) shall include scientists from academia, government, non-profit organizations, and industry. The CAT Team also shall include the WVDEP Environmental Advocate, Pam Nixon, as a representative o f West Virginia's citizens. The WVDEP, utilizing funds from an escrow account funded by DuPont, shall contract with a non-profit organization, the National Institute for Chemical Studies (NTCS), for the services described herein. Point o f contact for the NICS shall be Jan Taylor, Ph.D. The NICS shall subcontract with Marshall University's Center for Rural and Environmental Health for services in risk communication provided by James Becker, M.D. and his staff. Dr. Becker shall familiarize himself with the toxicity o f C8, the work performed by TERA as described herein, and attend public meetings to provide expertise in risk communication. The NICS shall subcontract with the non-profit scientific organization, Toxicology Excellence for Risk Assessment (TERA) whose point o f contact is Joan Dollarhide, Ph.D. The TERA shall provide services in toxicology and risk assessment. Work assignments, tasks, and deliverables are described below. CAT Team Member Organizations/ Representatives1/ General Functions WVDEP Dee Ann Staats, Ph.D. - Science Advisor - team leader; escrow funds disbursement oversight; project management and coordination; toxicology/risk assessment and communication; Pam Nixon - Environmental Advocate - advisor; NICS Jan Taylor, Ph.D. -contractor administrative oversight; James Becker, M.D. (Marshall University) - consultant in risk communication; TERA (point o f contact: Joan Dollarhide, Ph.D.)- consultant in toxicology/risk assessment; The parties may, in their discretion, elect to substitute their representatives with persons of similar qualifications. 000654 EID168219 M AH000591 DuPont Gerald Kennedy, Director o f Applied Toxicology and Health, Haskell Laboratory - reviewer toxicology; escrow funds disbursement oversight; John Whysner, M.D. - toxicology/risk assessment and communications; Paul Bossert - Washington Works Plant Manager - communications; The following members o f the CAT Team shall act as reviewers or advisors. WV Department of Health and Human Resources - Bureau for Public Health (WVDHHR-BPH) William T oom ey- Manager, Source Water Assessment Program - advisor; Barbara Taylor - Director, Office o f Environmental Health Services - advisor; Local representative - advisor; Environmental Protection Agency (EPA) Headquarters - Jennifer Seed - reviewer and advisor toxicology; Region III Philadelphia - Samuel Rotenberg, Ph.D. - reviewer and advisor toxicology/ risk assessment; Garth Connor - advisor hydrogeology; Roger Reinhart - reviewer and advisor Safe Drinking Water Act; Cincinnati - John Cicmanec, DVM - reviewer and advisor toxicology; Agency for Toxic Substances and Disease Registry' (ATSDR) Atlanta - Jolm Wheeler, Ph.D. - reviewer and advisor in toxicology/ risk assessment; Philadelphia - Lora Werner - coordinator for ATSDR; Non-CAT Team Efforts Other efforts are currently underway which may produce information for the CAT Team to utilize. The CAT Team will coordinate and communicate closely with these other efforts. These include: 1. Dupont's air modeling o f C8 emissions from the Washington Works plant; 2. WVDEP's air modeling o f C8 emissions from the Washington Works plant; 000655 C-2 EID168220 M AH000592 3. USEPA Draft Hazard Assessment which summarizes the available toxicity information regarding C8, to the extent completed prior to the assessment contemplated herein; 4. ATSDR's Health Consultation that estimates the risk to the community associated with C8 in drinking water from the Lubeck Public Service District, to the extent completed prior to the assessment contemplated herein. 5. Existing C8 concentrations in Lubeck Public Service District data. 6. Groundwater C8 Analysis (see GIST activities described in Attachment A) and Well Use Survey (see example survey in Attachment B) at the residences in the area o f the 3 landfills and the Washington Works Plant. Tasks of CAT Team The tasks to be performed by the CAT Team are described briefly in Table 1, and in more detail below. These tasks are discussed below within the context o f a Scope o f Work for both Dr. Becker and for TERA as well. Tasks o f the CAT Team shall be organized into three phases. Phase I includes those tasks necessary to prepare for and hold the first public meeting. In Phase II, TERA shall conduct such scientific tasks as: reviewing available toxicity and epidemiological studies; developing Provisional Reference Doses and Screening Levels for protection of human health; evaluating existing information relative to ecological health; and conducting one general risk assessment involving comparisons o f exposure concentrations to Screening Levels, for the three landfills and the Washington Works Plant, and the Lubeck Public Service District. TERA shall prepare a report on their findings. Phase III includes those tasks necessary to prepare for and hold the second public meeting. The results o f the C8 groundwater analysis and risk assessment shall be presented in the second public meeting. No communication between Dupont representatives and NICS, Dr. Becker, or TERA shall be permitted without the participation o f Dr. Staats. All information will be provided to Dr. Becker and TERA by WVDEP; thus, all information contributed to the effort by Dupont shall be sent in triplicate to Dr. Staats for forwarding to Dr. Becker and TERA. Phase I TASKA-1: First Public Meeting Two public meetings are anticipated for this project. The First Public Meeting shall occur in Phase I for the purposes o f introducing the CAT Team and other involved parties to the public; relating historical information on previous concentrations o f C8 in Lubeck Public Service District water supply; informing the citizens o f the ensuing activities; and inviting the public to participate by cooperating with sampling and survey efforts in the Groundwater C8 Analysis and Well Use Survey. In order to prepare for the 000656 C-3 EID168221 M AH000593 First Public Meeting, CAT Team members shall familiarize themselves with the available toxicological information concerning C8. A CAT Team meeting shall be held immediately prior to the first public meeting to: (1) conduct a site visit to the three landfills and the Washington Works Plant, and surrounding residential areas; (2) discuss the toxicity o f C8 and other pertinent data; (3) prepare an agenda for the public meeting; (4) coordinate and prepare for the public meeting. Finally, the First Public Meeting will be held and public questions and comments will be recorded by WVDEP. TABLE 1. TASKS OF CAT TEAM Task A: Public Meetings (two meetings are anticipated) Objective: to inform the local citizens o f the following: (in Meeting #1) intent to perform a groundwater well use survey and analysis for C8; intent to develop Screening Levels; and to ask for their cooperation in conducting the water use survey; and (in Meeting #2) results o f survey, chemical analysis, and risk assessment. Note that an interim public meeting may be required should six months pass from the first public meeting and the CAT Team Final Report has not been issued. Primary Responsibility: Staats____________________________ _______________ _______ Task B: Development o f Provisional Reference Doses Objective: to develop Provisional References Doses for C8 for the inhalation and ingestion (and dermal, if possible) routes o f exposure. Primary Responsibility: TERA___________________________________ _ Task C: Development o f Screening Levels Based on Protection o f Human Health Objective: to utilize the Provisional Reference Doses to develop human health risk-based Screening Levels for C8 in air, water, and soil. Note a determination o f the potential carcinogenicity o f C8 will be conducted as well. Primary Responsibility: TERA________ _______________ _______ Task D: Ecological Data Review Objective: to review available information to determine whether sufficient studies have been performed and data have been collected to develop screening criteria for ecological receptors. Primary Responsibility: TERA_____________________________________ Task E: Draft Report and Final Report Objective: to present and discuss the results o f the above tasks. Primary Responsibility: TERA__________________________________________________ Phase II Tasks B, C. D. and E Development o f Provisional Reference Doses and Screening Levels, and Risk Assessment In Phase II, TERA shall conduct the toxicological and risk assessment activities. After having reviewed the toxicological information regarding C8 provided by WVDEP, TERA shall consult with toxicologists on the CAT Team, as coordinated by Dr. Staats, regarding its proposed approach for this project. Following such consultation, TERA 000657 C-4 EID168222 M AH000594 shall develop Provisional Reference Doses for C8 for the oral, inhalation, and dermal (if possible) routes o f exposure. Then TERA shall calculate Screening Levels for water, soil and air based on the risk factors they have estimated. TERA shall perform one general risk assessment involving comparison o f exposure concentrations to Screening Levels for the three landfills and the Washington Works Plant, and the Lubeck Public Service District water supply, that focuses on current risk to human health, including workers and residents. This risk assessment shall include: (1) identification o f reasonably anticipated land use, surface water and groundwater use; (2) identification o f receptors; (3) identification o f exposure pathways; (4) identification o f exposure concentrations; and (5) comparison o f exposure concentrations to appropriate Screening Levels. TERA shall utilize data obtained from the other efforts discussed above such as air modeling; groundwater C8 concentrations in residential and public wells; residential groundwater well use survey; the USEPA's Draft Hazard Assessment; and ATSDR's Health Consultation (if available). TERA also shall review available information to determine whether sufficient studies have been performed and data have been collected to develop screening criteria for protection o f ecological health, particularly aquatic life. TERA shall prepare a draft and a final document that discusses the results o f their efforts and summarizes the data utilized from other efforts. As the tasks o f the CAT Team and other involved parties' progress, data gaps and research recommendations may become evident. These shall be included in TERA's report as suggestions for further research to elucidate the toxicity o f C8. Phase III Second Public Meeting The purpose o f the Second Public Meeting is to present to the citizenry the results o f the efforts o f the GIST and CAT Teams including C8 concentrations in groundwater from residential wells and public wells the screening levels and the general risk assessment. Air modeling results o f the efforts o f WVDEP and Dupont will be discussed also. The WVDEP will address any further actions that may be necessary. 000658 C-5 EID168223 M AH000595 SCOPE OF WORK FOR JAMES BECKER, M.D. Dr. Becker is a medical doctor specializing in environmental health at the Marshall University School o f Medicine Center for Rural and Environmental Health. He will be assisting the WVDEP in his specialty area o f risk communication at the two anticipated public meetings. The specific tasks assigned to Dr. Becker are described below. Phase I Task A -l: First Public Meeting Dr Becker will assist in preparation for the first public meeting, and attend the meeting providing expertise in risk communication . He will familiarize himself with the available toxicological data, which will be provided to him by WVDEP, with particular emphasis on the epidemiological studies. Note that the toxicological data already has been summarized in the Draft Hazard Assessment prepared by USEPA. No literature search or document retrieval will be required. Specific subtasks required in Phase I to prepare for the first public meeting are described below: Subtask 1 - Familiarization with toxicological data provided by WVDEP including but not limited to: a. 8 compact discs o f information provided to USEPA under TSCA by 3M Corp (note only a small portion o f tills information concerns C8); b. Draft Hazard Assessment document from USEPA; c. ACGEH Threshold Limit Value (TLV). d. Journal articles and other information provided by WVDEP. Subtask 2 - Attend a meeting prior to the first public meeting to: a. conduct a site visit o f the 3 landfills and the Washington Works Plant, and local residential areas; b. discuss and prepare an agenda; c. discuss the toxicology and risks associated with C8 with the other CAT Team members. Subtask 3 - Attend First Public Meeting Phase III Task A-2 Second Public Meeting Dr Becker will assist in preparation for the second public meeting, and attend the meeting providing expertise in risk communication. The following subtasks will be required: Subtask 1 - Familiarization with the toxicological and risk assessment report prepared by TERA; 000659 C-6 EID168224 M AH000596 Subtask 2 - Attend a meeting prior to the second public meeting to: a. discuss the toxicology and risks associated with C8 with the other CAT Team members; b. discuss and prepare an agenda. Subtask 3 - Attend Second Public Meeting Note that the second public meeting is assumed to be the final public meeting; however, results o f data collection may warrant additional public meetings and an expansion o f the Scope o f Work. 00066 C-7 EID168225 M AH000597 SCOPE OF WORK FOR TERA TERA (Toxicology Excellence for Risk Assessment) is a non-profit organization that applies sound toxicological data to the risk assessment process to find common ground between environmental, industry, and government groups. TERA will be providing services in toxicology and risk assessment. TERA scientists will be developing risk factors and screening criteria; and conducting one general risk assessment for the 3 landfills, Lubeck Public Service District water supply and the Washington Works Plant. The specific tasks assigned to TERA are described below. Phase II Tasks B, C, D, and E: Development of Provisional Reference Doses and Screening Levels, and General Assessment of Risk Subtask 1 - TERA staff will familiarize themselves with the toxicological data provided to by WVDEP. No literature search or document retrieval will be required. Toxicological data to be provided to TERA shall include but is not limited to the following: a. 8 compact discs o f information provided to USEPA under TSCA by 3M Corp (note only a small portion o f this information concerns C8); b. USEPA Draft Hazard Assessment for C8; c. Journal articles and other information submitted to WVDEP by DuPont. Subtask 2 - TERA staff will: a. identify all possible critical toxicological studies suitable for developing Reference Doses for the oral, inhalation, and dermal (if possible) routes of exposure; b. outline methodology for developing said Reference Doses and for developing Screening Levels for air, water, and soil based on said Reference Doses corresponding to each critical study identified in subtask 2-a; c. convene a meeting at the TERA facility in Cincinnati, Ohio, to present their findings in subtask 2-a and 2-b, and consult with CAT Team toxicologists as coordinated by Dr. Staats; d. finalize Reference Doses and Screening Levels based on recommendations o f the CAT Team toxicologists as coordinated by Dr. Staats. Subtask 3 - TERA shall conduct one general risk assessment for the three landfills and Washington Works Plant, and the Lubeck Public Service District water supply based on current risk to human health. This risk assessment shall include: a) identification o f reasonably anticipated land use, surface water and groundwater uses; 000661 C-8 EID168226 M AH000598 b) identification o f receptors; c) identification o f exposure pathways; d) identification o f exposure concentrations; e) comparison o f exposure concentrations to appropriate Screening Levels; TERA shall utilize the following data in the risk assessment process: a) air modeling data from DuPont; b) air modeling data from WVDEP; c) water use data from the Well Use Survey; d) groundwater data from the Groundwater Well Analysis o f C8 for residential wells; e) drinking water data from Lubeck Public Service District wells; f) any available ATSDR Health Consultation that assesses potential health effects from exposure to C8 in public supply drinking water. Subtask 4 - TERA shall review the ecological data and determine whether there is sufficient information to support the development o f a C8 Screening Level for protection o f ecological health Subtask 5 - TERA shall compile and discuss the results o f the above tasks into a comprehensive report (draft and final versions), which also refers to and provides a brief summary o f the following: a) USEPA's Draft Hazard Assessment o f C8; b) DuPont's air modeling data; c) WVDEP's air modeling data; d) groundwater data from the Groundwater C8 Analysis and Well Use Survey o f Local Residents, and Lubeck Public Service District; e) ATSDR Health Consultation that assesses potential health effects from exposure to C8 in public supply drinking water, if available. Additionally, TERA shall include in the report any insights or recommendations for future research gleaned during this process that would further elucidate-the toxicity o f C8. Also, TERA shall provide in the report o f a summary discussion o f the relevance the carcinogenicity o f C8 in rats to humans. 0 0 0 6 6 *; C-9 EID168227 M AH000599