Document 3QwkL2RQxyB572y9Mkejeg4D3

AR226-2637 AR226-2637 PHASE I SUPPLEMENTAL RCRA FACILITY INVESTIGATION REPORT DUPONT FAYETTEVILLE WORKS FAYETTEVILLE, NORTH CAROLINA Preparedfo r DuPont Fayetteville Works Highway 87 South Fayetteville, NC 28302 RCRA Permit No. NCD047368642-R1 Date: May 27,2004 Project No. : 504321 CORPORATE REMEDIATION GROUP An Alliance between DuPont and URS Corporation-North Carolina 6324 Fairview Road Charlotte, North Carolina 28210 investigation Report Table of Contents TABLE OF CONTENTS Executive Summary................................................................................................................1 1.0 Introduction.................................................................................................................... 3 1.1 Purpose......................................................................................... 3 1.2 Supplemental Phase I Objectives.........................................................................4 2.0 Background.................................................................................................................... 5 2.1 Site Location.........................................................................................................5 2.2 Plant Setting.................................................................................................. 5 2.2.1 Regional Setting....................................................... 5 2.2.2 Site Setting..............................................................................................6 2.3 Plant Site Operations.............................................................................................7 2.4 Regulatory Information........................................................................................ 7 2.5 Previous Investigations.........................................................................................8 2.5.1 RCRA Facility Assessment.................................................................... 8 2.5.2 RCRA Confirmatory Sampling.................................................... 8 2.5.3 RCRA Confirmatory Sampling (Supplemental).................... 8 2.5.4 Former Fire Training A rea.....................................................................9 2.5.5 Ammonium Perfluoroeoctanoate (C-8) Sampling.................................9 2.5.6 P haseIR F I..............................................................................................9 2.6 Site Conceptual Model........................................................................................10 3.0 Field Investigation Summary.......................................................................................11 3.1 Piezometer Installations.....................................................................................11 3.1.1 Objective............................................................................................... 11 3.1.2 Methodology..........................................................................................11 3.1.3 Piezometer Construction Materials......................................................11 3.2 Groundwater Sampling.......................................................................................12 3.2.1 Objectives.............................................................................................. 12 3.2.2 Methodology..........................................................................................12 3.3 Surface Water Sampling.....................................................................................12 3.3.1 Objectives.............................................................................................. 12 3.3.2 Methodology..........................................................................................12 3.4 Lithologic Investigation.....................................................................................12 3.4.1 Objectives.............................................................................................. 12 3.4.2 Methodology..........................................................................................13 3.5 Deviations from the Work Plan1......................................................................... 13 3.6 Decontamination Procedures.............................................................................13 3.7 Investigative Derived W aste........................... ..............;...................................13 3.8 Quality Assurance/Quality Control Program.................................................... 14 4.0 Results of Phase I Supplemental RFI Investigation...................................................16 4.1 Results................................................................................................................. 16 Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC investigation Report Table of Contents 4.2 QA/QC Analytical Results................................................................................. 16 4.2.1 QA/QC Sample B lanks........................................................................ 16 4.2.2 Duplicates..............................................................................................16 4.3 Analytical Screening Process............................................................................. 17 4.3.1 Groundwater Analytical Screening Process........................................ 17 4.4 SWMU and AOC Analytical Results................................................................17 4.4.1 SWMU 6 - Process Sewers..................................................................17 4.4.2 Fire Training A rea................................................................................ 19 5.0 Significance of Results............................................................................................... 21 5.1 Revised Site Conceptual Model........................................................................ 21 5.1.1 Topography........................................................................................... 21 5.1.2 Lithology/Hydrogeology......................................................................21 5.1.3 Contaminant Distribution.....................................................................23 6.0 Conclusions and Recommendations...........................................................................25 6.1 Conclusions.........................................................................................................25 6.2 Recommendations and Path Forward............................................................... 26 7.0 References.................................................................................................................... 27 Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC ii investigation Report Table of Contents Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 TABLES Groundwater Level Elevations Piezometer and Monitoring Well Construction Details Field Parameter Summary SWMIJ 6 Monitoring Well Groundwater Detections Surface Water Analytical Detections Former Fire Training Area Groundwater Detections Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 FIGURES Site Location Map Site Layout with SWMU Locations Piezometer, Monitor well and CPT Boring Locations SWMU 6 Potentiometric Map Former Fire Training Area Potentiometric Map SWMU 6 Groundwater Exceedances Surface Water Analytical Detections Former Fire Training Area Groundwater Exceedances Cross-Section Location Map A-A' Cross-Section B-B' Cross-Section C-C' Cross-Section Top o f Clay/Clayey Silt Layer Contour Map Clay/Clayey Silt Layer Isopach Map Site-Wide Groundwater Potentiometric Map Proposed Monitor Well Location Map Appendix A Appendix B APPENDICES CPT Lithologic Logs , Analytical Data Sheets Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC iii investigation Report (revised) Executive Summary EXECUTIVE SUMMARY This Resource Conservation Recovery Act (RCRA) Facility Investigation (RFI) report has been prepared in accordance with requirements set forth in RCRA Permit No. NCD047368642-R1 (permit) Appendix B issued by the North Carolina Department of Environment and Natural Resources (NCDENR) to the DuPont Fayetteville Works (site) on December 2, 1997. The permit stipulates that DuPont prepare a Phase I RFI Report based on the Phase I RFI Work Plan to characterize releases identified during previous investigations completed at the site. The Phase I RFI work plan was submitted on November 8, 2001. A revised Phase I RFI work plan was submitted to the NCDENR on June 16, 2002 and subsequently approved by the NCDENR. Comments on the RCRA Phase I Report were forwarded by NCDENR personnel on May 14, 2003 and June 5, 2003. Subsequent conference calls on May 29, 2003 and June 27, 2003 were held between DuPont Corporate Remediation Group (CRG) personnel and NCDENR personnel to discuss the NCDENR RCRA Phase I Report comments and a path forward. The path forward agreed to in the conference calls was to proceed with the Phase I Report recommendations. DuPont provided a response to the comments associated with the Phase I Report on August 18, 2003. The purpose o f the Phase I Supplemental RFI was to further characterize potential releases to the environment from those SWMUs/AOCs identified during the Phase I RFI as requiring further investigation. Based on the Phase I RFI prioritization, one SWMU and one AOC were carried forward to the Phase I Supplemental RFI. The specific objectives of the Phase I Supplemental RFI were to: 1. Characterize groundwater flow conditions in the surficial aquifer underlying the site. 2. Resample existing monitor wells and piezometers located in the vicinity of SWMU 6 (common sump) to further characterize groundwater quality. 3. Collect an additional set of groundwater samples from monitor wells installed in the vicinity of the Former Fire Training Area to confirm the remaining limited area o f impacted soil is not adversely impacting shallow groundwater. 4. Complete a lithologic investigation for the presence of the clay layer and evaluate the presence of seepage faces along the slopes leading to the Cape Fear River. 5. Conduct a formal risk evaluation to support finalization of the RFI phase and remedial decision-making. Based on the findings o f the Phase I Supplemental RFI as well as the refined Site Conceptual Model the following conclusions are offered: SWMU 6 ' ? Only one organic (methylene chloride) and one inorganic (chloride) compound were detected in monitor wells downgradient of the SWMU 6 (common sump) above the respective PQL and NCDENR 2L groundwater quality standards. Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC 1 investigation Report (revised) Executive Summary ? Although a NCDENR 2L groundwater standard is not available for C-8, the low levels o f C-8 detected in the groundwater samples collected from monitor wells present in the vicinity of SWMU 6 (common sump) are well below recognized risk-based drinking water standards. Former Fire training Area ? The lead detected in the groundwater samples appears to be naturally occurring. No other constituents were detected above the DENR 2L groundwater quality standards. Site Conceptual Model ? Potential vertical migration of shallow surficial groundwater at the site is retarded by the presence of a continuous stiff clay/clayey silt layer underlying the investigated areas. ? Groundwater flow in the surficial aquifer is controlled by the topography of the underlying clay/clayey silt layer except in the vicinity of SWMU 6. ? A localized groundwater mound potentially exists in the vicinity of the river water holding basins which may cause groundwater flow in the vicinity of SWMU 6 (common sump) to flow against the direction of the clay/clayey silt layer dip. ? Seepage faces were observed in a portion o f the drainage channel located to the northeast of the SWMU 6 (common sump). ? Data collected during the Phase I Supplemental RFI as well as historical data in conjunction with existing administrative controls at the site indicates that no immediate threat to human health or the environment exists as a result o f operations at the site. Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC 2 investigation Report (revised) Introduction 1.0 INTRODUCTION In January 1998, the North Carolina Department of Environment and Natural Resources (NCDENR) reissued the facility a Resource Conservation and Recovery Act (RCRA) Part B Permit (NCD047368642) and remains in effect for 10 years. Since 1996 several investigations have occurred at the facility. A detailed discussion of the previous investigations can be found in the associated reports and a summary discussion can be found in the RCRA Phase I Report dated April 14, 2003. These investigations along with the associated report submittal dates include: RCRA Facility Assessment - December 1996 RCRA Confirmatory Sampling - May 1999 RCRA Confirmatory Sampling (Supplemental) - June 1999 Former Fire Training Area Investigation - November 2001 January 2003 Baseline C-8 Sampling RCRA Phase I Investigation - April 2003 Comments on the RCRA Phase I Report were forwarded by NCDENR personnel on May 14, 2003 and June 5, 2003. Subsequent conference calls on May 29, 2003 and June 27, 2003 were held between DuPont Corporate Remediation Group (CRG) personnel and NCDENR personnel to discuss the NCDENR RCRA Phase I Report comments and a path forward. The path forward agreed to in the conference calls was to proceed with the Phase I Report recommendations. These recommendations are discussed in the section below. DuPont provided a response to the comments associated with the Phase I Report on August 18, 2003. 1.1 Purpose The purpose o f this document is to present the technical approach and procedures used during the Phase I Supplemental RFI, discuss the results of analytical data and evaluate the significance o f the results based on the Phase I Supplemental RFI. This documents purpose is to also make recommendations for the further investigation or remedial action where warranted. The Phase I Supplemental RFI is organized into the following seven sections: ? Section 1.0 is the introduction, which presents the purpose and objectives o f the Phase I Supplemental RFI. ? Section 2.0 provides the plant operation history, plant setting, previous investigations summary, and explanation o f the site conceptual model concept. ? Section 3.0 provides the investigation summary which details the technical approach implemented for the Phase I Supplemental RFI, deviations from the work plan, and the quality assurance/quality control (QA/QC) program. Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC investigation Report (revised) Introduction ? Section 4.0 presents the data screening process; the laboratory analytical results by SWMU/AOC (including QA/QC sample results) and details the site-specific geology/hydrogeology. ? Section 5.0 discusses the revised site conceptual model (SCM) as it pertains to the significance o f the results, including identification o f constituents of concern (COCs), potential migration pathways and receptors, contaminant fate as well as SWMU reprioritization. ? Section 6.0 presents the conclusions and recommendations, identification of data gaps, and a discussion of those SWMUs/AOC warranting further investigation. ? Section 7.0 presents the list of references used in this report. 1.2 Supplemental Phase I Objectives The purpose of the Phase I Supplemental RFI was to further characterize potential releases to the environment from those SWMUs/AOCs identified during the Phase I RFI as requiring further investigation. Based on the Phase I RFI prioritization, one SWMU and one AOC were carried forward to the Phase I Supplemental RFI. The specific objectives o f the Phase I Supplemental RFI were to: 6. Characterize groundwater flow conditions in the surficial aquifer underlying the site. 7. Resample existing monitor wells and piezometers located in the vicinity of SWMU 6 (common sump) to further characterize groundwater quality. 8. Collect an additional set of groundwater samples from monitor wells installed in the vicinity of the Former Fire Training Area to confirm the remaining limited area of impacted soil is not adversely impacting shallow groundwater. 9. Complete a lithologic investigation for the presence o f the clay layer and evaluate the presence o f seepage faces along the slopes leading to the Cape Fear River. 10. Conduct a formal risk evaluation to support finalization of the RFI phase and remedial decision-making. Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC 4 investigation Report (revised) Background 2.0 BACKGROUND This section presents information regarding site location, operational history and the environmental setting. This section also provides a description o f the units and the waste characteristics of SWMUs/AOCs investigated during the Phase I Supplemental RFI. 2.1 Site Location E.I. du Pont de Nemours and Company (DuPont) owns and operates the Fayetteville Works Plant located in Duart Township, Bladen County, North Carolina. The facility is located 15 miles southeast of the city o f Fayetteville onN C Route 87, along the BladenCumberland county line (Figure 1). The DuPont property was purchased as parcels from several families in 1970. The first manufacturing area o f the Fayetteville Works was constructed in the early 1970s. The facility is currently a manufacturer o f plastic sheeting, fluorochemicals, ammonium perfluorooctanoate (C-8) and intermediates for plastics manufacturing. A former manufacturing area, which was sold in 1992, produced nylon strapping and Elastomeric Tape. The geographic location of the facility is 3450'30" North latitude, 7850'00" West longitude. The site contains 2,177 acres of relatively flat undeveloped open land and woodland bounded on the east by the Cape Fear River, NC Highway 87 on the west, and farmland on the north and south. Figure 2 depicts the facility layout. In addition to the manufacturing operations, DuPont operates a wastewater treatment plant (WWTP) for treatment of process wastewater. Hazardous waste generated as a result of the chemical process and laboratory analyses are currently managed in drums at the Hazardous Waste Container Storage Area prior to being shipped offsite for treatment, disposal, or recycling. 2.2 Plant Setting 2.2.1 Regional Setting Regional Climate Relatively mild winters, hot summers and abundant rainfall characterize the climate in Bladen County. Temperatures range from an average monthly high o f 91 F in July to an average monthly low of 33 F in January. Average rainfall ranges from a monthly high of 5.59 inches in July to a monthly low o f 2.97 inches in November. Regional Topography . The region is generally level to gentle sloping. However, approaching the Cape Fear River and its tributaries the slopes steepen. Regional Geology/Hydrogeology The plant is located in th northwestern portion o f Bladen County. Bladen County is situated within the Coastal Plain Physiographic Province. The Coastal Plain consists o f a Fayetteville Supp RFI-I Reportdoc Nov. 12. 04 Charlotte, NC investigation Report (revised) Background seaward thicking wedge of sedimentary deposits ranging in age from Cretaceous to Recent. Paleozoic age metamorphic and igneous rocks underlie these deposits. In the northern portion of Bladen County these "basement" rocks are approximately 400 feet below the surface. A detailed description of the Coastal Plain sediments is presented in the Confirmatory Sampling Report. Based on the Geologic Map o f North Carolina (1985), the site is underlain by the Black Creek Formation. The Black Creek Formation is characterized by lignitic clay, gray to black, and contains thin beds and laminae of fine-grained micaceous sand as well as thick lenses of cross-bedded sand. The upper portion o f the formation may also contain glauconitic, fossiliferous clayey sand lenses. The Black Creek Formation and surficial deposits are the principal aquifers in the site area. The layers of sand within the Black Creek Formation supply the groundwater locally, especially for the larger wells. The surficial deposits in the site area provide water for many small domestic wells. 2.2.2 Site Setting Site Topography and Drainage The Cape Fear River is located along the eastern property boundary o f the plant approximately 1850 feet from the eastern portion of the manufacturing area. Willis Creek, a tributary of the Cape Fear River is located in the northern portion of the site approximately 3,000 feet from the manufacturing area. A drainage channel leading to the Cape Fear River is located just south of the plant area and is used as the outfall area covered by NPDES Permit Number NC003573. Portions of the Georgia Branch coincide with the southern boundary o f the site. A drainage channel is located approximately 100 feet to the northeast of the eastern most potion of the manufacturing area. The plant facilities are located on a plateau at an approximate elevation of 150 feet above mean sea level. The plant is situated approximately 70 feet above the 100 and 500-year flood plains and at least 1,000 feet from the 100-year flood plains nearest approach. Site Geology The soil on the Fayetteville Works Plant site falls within the Norfolk-Goldsboro-Raines general classification (Soil Survey of Bladen County, 1990). These soils are located on old, high stream terraces in the northern part of Bladen County. They range in being well to poorly drained soils that have a sandy or loamy surface layer and loamy subsoil. Based on historical geotechnical boring logs and boring logs generated during the Confirmatory Sampling Event as well as the Phase IRFI, three distinct soil layers were observed. The surficial layer consists o f a brown to tannish, silty, medium to fine grain sand that coarsens to medium grain well-sdrted sand near its base. The unit ranges in thickness from 15 to 18 feet. This sand layer is underlain by a stiff grey to black lignatic clay layer. Based on geotechnical borings in the southeastern portion of the manufacturing area, the clay layer was approximately five to eight feet thick. The thickness o f the clay layer in the central and eastern portions of the manufacturing area is uncertain because borings were terminated at the top of the unit. Beneath the clay layer is a silty sand unit based on the geotechnical borings. Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC 6 investigation Report (revised) Background Site Hydrogeology General groundwater flow is expected to be to the east in the direction o f the Cape Fear River. However, shallow localized groundwater flow beneath the investigated areas appears to coincide with the dip direction of the underlying clay layer and does not flow towards the Cape Fear River as anticipated with the exception of groundwater flow in the vicinity of SWMU 6. Groundwater flows in a northeasterly direction at SWMU 6 (Figure 4). The potentiometric surface is relatively flat in the area o f the common sump and the gradient increases in the northeast portion o f the manufacturing area that coincides with an increase topographic relief. Groundwater flows in a northeasterly direction. The horizontal gradient changes from 0.0012 feet per foot (ft/ft) to 0.025 ft/ft in the northeast portion of the area. Flow in the vicinity o f the Former Fire Training Area is to the west and the gradient is relatively flat (Figure 5). The horizontal gradient was calculated to be 0.006 ft/ft in a westerly direction. Groundwater elevation data is summarized in Table 1. 2.3 Plant Site Operations The DuPont Fayetteville Works consists of four main areas, where the following products are manufactured: Area I ? automotive safety glass. Area II ? Nafion Fluorocarbon membrane for electronic cells. ? Fluorocarbon intermediates for Nafion membrane, T Viton elastomers. ? Polysiloxane Abrasion Resistance Coating (PARC). Area III ? Dymetrol nylon strapping. ? Area IV 9 Ammonium Perfluorooctanoate (C-8) 2.4 Regulatory information The Fayetteville Works operates under permits from several regulatory programs; RCRA/solid waste, NPDES/water quality and air. RCRA/Solid W aste Permits: The facility received its initial RCRA Permit (NCD047368642) to operate a hazardous waste container storage area and tanks in February of 1983. An amended Part A application was last submitted in 1991 to document upgrades to its fluorocarbon waste treatment and tank system. The RCRA Part B permit application submitted in August 1993, identified a total of 71,750 gallons of container storage capacity at the container storage area. Waste stored included characteristic wastes (D001, D002, D003, D007, D009, and D029) and listed wastes (F002, F003, and F005). This permit was reissued and became effective on January 1, 1998, and will remain effective for 10 years. Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC 7 investigation Report (revised) Background 2.5 Previous Investigations Six investigations have been conducted at the DuPont Fayetteville Works for this facility from September 1993 through April 2003. The following paragraphs describe the findings from each o f these investigations. Locations o f the investigated SWMUs/AOCs are depicted on Figure 2. 2.5.1 RCRA Facility Assessment A December 1996 RCRA Facility Assessment (RFA) identified 24 Solid Waste Management Units (SWMUs) and four AOCs at the site. Based in part on the RFA, the NCDENR identified three SWMUs and one AOC that required a Confirmatory Sampling (CS) investigation. 2.5.2 RCRA Confirmatory Sampling The objective o f the Confirmatory Sampling (CS) Event was to determine if any o f the four units (three SWMUs and one AOC) or the additional area (Former Fire Training Area) warranted an RFI. An RFI is required if there has been a release of hazardous constituents to the environment. Results of the CS Event conducted in March 1999 are documented in the Confirmatory Sampling Report dated May 3, 1999. As discussed in this report, soil samples collected from SWMU 6 (Process Sewer System) and the Former Wastewater Treatment Lagoons (SWMU 9A&B) contained low levels of several volatile organic compounds (mainly acetone and methylene chloride). Two metals (iron and nickel) exceeded the upper tolerance background limit in two of the fifteen soil borings. The results of the CS were reviewed with personnel from the North Carolina Department o f Environment and Natural Resources (NCDENR) during a meeting at the Raleigh, North Carolina offices held June 8,1999. It was determined that several of the volatile organic compounds detected were attributed to laboratory contamination. A supplemental sampling program to confirm the presence o f the volatile organic compounds detected in the confirmatory sampling was recommended. 2.5.3 RCRA Confirmatory Sampling (Supplemental) The NCDENR requested additional information (June 8, 1999) regarding the CS Event. As a result additional sampling activities were conducted to provide information for determining whether the presence of several volatile organic compounds detected during the initial CS sampling originated as a result of laboratory contamination. Also, this information was used for further characterization and determination o f potential releases from selected units (SWMUs and AOCs) at the DuPont Fayetteville Works. The findings were submitted in the Confirmatory Sampling Supplemental Report dated December 3, 1999 The Information obtained during the CS investigation was used to construct a preliminary site conceptual model (SCM) which was presented in the report. Upon review of this data it was determined that additional characterization was necessary at SWMU 6 (Process Sewer System common sump area) and SWMU 9 (Former Wastewater Treatment Lagoons). Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 8 investigation Report (revised) Background 2.5.4 Former Fire Training Area During the completion of activities associated with the construction o f a roadway at the DuPont Fayetteville Works, an area was uncovered that was used to train on-site employees in fire extinguishing techniques. Upon discovering the area, the site environmental manager notified representatives from the North Carolina Department of Natural Resources (NCDENR) Waste Management Division. It was decided to include this area in the RCRA Confirmatory Sampling (CS) that was ongoing at the site. Investigative activities completed included the collection and analysis o f a series o f soil samples to determine if the operation o f the former fire training area impacted subsurface soils. Remedial efforts included the excavation of soils potentially impacted by the operations and subsequent backfilling with clean soil. A detailed discussion of these activities are contained in the Excavation Sampling Report, Former Fire Training Area dated November 8, 2001. However, samples collected at the bottom o f the excavation (immediately above the water table) indicated potential for impact to shallow groundwater. 2.5.5 Ammonium Perfluoroeoctanoate (C-8) Sampling As part of a Letter of Intent (LOI) with the United States Environmental Protection Agency (EPA), DuPont committed to monitor groundwater and surface water for ammonium perfluoroeoctonate (C-8) at the site and to report results for the preceding year to EPA on a biennial basis. A copy of the LOI was forwarded to NCDENR in the Revised RCRA Phase I Supplemental Work Plan (see, in particular, Addendum III o f the LOI for commitments concerning C-8 manufacture). The annual sampling results were forwarded to DENR in a report dated March 2003. Analytical results indicated a trace amount of C-8 in monitor well NAF-01 located upgradient of SWMU 6 (common sump). Additional sampling of existing monitor wells in the vicinity of the common sump was conducted as part of the Phase I Supplemental RFI and are discussed in Section 4.4.1 of this report. 2.5.6 Phase I RFI SWMU 6 ? The soil sample collected adjacent to Manhole 1 associated with SWMU 6 did not indicate the presence of compounds detected during the CS at concentrations above the method detection limit. Detected constituents appear to be associated constituents contained in runoff from the adjacent asphalt road ponding in the vicinity of Manhole 1 and infiltrating into the soils. ? One organic compound (methylene chloride) and two inorganic compounds (chloride and fluoride) were detected in monitor wells downgradient of the SWMU 6 (common sump) above the DENR 2L groundwater quality standards. Former Fire training Area ? The lead detected in the groundwater sample collected from upgradient monitor well FTA-01 appears to be naturally occurring. No other target inorganic constituents were detected above the DENR 2L groundwater quality standards. Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC investigation Report (revised) Background Reprioritization ? An unknown ranking was listed for potential release to surface water for SWMU 6 due to the potential for seepage faces northeast of the unit. ? The ranking for release to air with respect to indoor air quality for SWMU 6 was changed from NFA to unknown due to the presence of volatile organics in the groundwater, the shallow nature of groundwater and the proximity of buildings. 2.6 Site Conceptual Model DuPont utilizes the SCM to develop a representation of the chemical and physical characteristics of a site in order to focus investigation efforts and remedial decision making. A conceptual model of a site, as defined by ASTM (E1689-95), may include the following information: identification o f potential contaminants; identification and characterization of source(s) o f contamination; determination of potential migration pathways through environmental media such as groundwater, surface water, soils, and air; establishment of background areas; identification and characterization of potential environmental receptors (human and ecological); and determination o f the limits of the study area or system boundary. In summary it describes the physical/chemical environmental status of a site at a particular time in its history. The initial site conceptual model is presented in detail in the Supplemental CS Report dated December 3, 1999. The revised site conceptual model utilizing data from the CS, Phase IR FI and Phase I Supplemental RFI for the DuPont Fayetteville site is described in Section 5.1. Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC 10 investigation Report (revised) Field Investigation Summary 3.0 FIELD INVESTIGATION SUMMARY This section describes the general sampling procedures that occurred during the- Phase I Supplemental RFI and includes decontamination and quality assurance/quality control (QA/QC). Sampling procedures followed the guidance documents contained in Section 3.0 o f the Phase I Supplemental RFI Work Plan. All field procedures were documented in bound field books. These books are filed with all documentation regarding the Phase I Supplemental RFI in the CRG Charlotte, North Carolina Office. 3.1 Piezometer Installations The objectives of the piezometer installations, along with a discussion o f the methodology and construction details are presented below. Table 2 contains the piezometer construction details. 3.1.1 Objective A total of 8 shallow piezometers (PZ-11 through PZ-20) were installed during the Phase I Supplemental RFI to characterize groundwater flow in the surficial aquifer underlying the site. The locations of the piezometers are depicted in Figure 3. Appendix A presents the CPT lithologic logs. 3.1.2 Methodology Piezometers were installed utilizing direct push technology. A cone penetrometer (CPT) was equipped with two-inch stainless steel rods that were hydraulically pushed into the ground. Prior to installing the piezometer, the lithology of the subsurface was logged using CPT technology. The borings were terminated at the top of the clay layer underlying the site. Once the termination depth was reached, continuous 2-inch rods were advanced to the boring terminus and a %-inch temporary piezometer with a pre-packed, five-foot screen was installed through the rods. 3.1.3 Piezometer Construction Materials Piezometers were constructed of %-inch diameter, flush jointed schedule 40 PVC pipe. The screen interval was machine-slotted with 0.010-inch openings. The pre-packed sand extended over the screen interval approximately one-foot. A pre-packed three-foot bentonite plug was placed above the sand pack. A PVC riser was installed to approximately two-feet above the ground surface. The borehole was then allowed to collapse around the piezometer casing. Phase I Supplemental RFI piezometer construction details are summarized in Table 2. Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC 11 investigation Report (revised) Field Investigation Summary 3.2 Groundwater Sampling 3.2.1 Objectives The objectives o f the groundwater sampling was to further characterize groundwater quality at SWMU 6 (common sump) and the Former Fire Training Area. Groundwater samples were collected via dedicated Teflon bailers as requested by DENR. 3.2.2 Methodology A peristaltic pump with dedicated polyethylene tubing was used to purge the groundwater from each sampling point. Once three well bore volumes were purged or the sampling point was purged dry, groundwater samples were collected using Teflon bailers. Upon completion of purging activities, a dedicated Teflon bailer was lowered into the well and a groundwater sample was collected. Samples analyzed for C-8 were collected using low flow sampling techniques. Dedicated polyethylene tubing was lowered into the well. A peristaltic pump was used to purge groundwater at a flow not exceeding 0.5 liters per minute. Groundwater parameters (i.e., pH, conductivity, temperature, turbidity) were collected during purging activities. When the individual monitored parameters differed by less than 10% the groundwater sample was collected. 3.3 Surface Water Sampling 3.3.1 Objectives The objectives o f the surface water sampling was to evaluate the potential for discharge o f shallow groundwater in the drainage channel located to the northeast of SWMU 6 (common sump). 3.3.2 Methodology Surface water samples were collected at four locations along the drainage channel. One upgradient, one at the location of seepage faces observed in the banks of the channel, and two down gradient samples that correspond to areas beneath the clay/clayey silt layer outcropping. Surface water samples were collected using a Teflon scoop and poured directly into laboratory supplied containers. The scoop was decontaminated between each sample to minimize the potential for cross contamination. 3.4 Lithologic Investigation 3.4.1 Objectives The objectives of the lithologic investigation were to investigate the presence of the clay layer and evaluate the presence of seepage faces along the slopes leading to the Cape Fear River located northeast of SWMU 6. Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC investigation Report (revised) Field Investigation Summary 3.4.2 Methodology A CPT rig was utilized to collect subsurface lithology data. Borings were advanced on an approximate 600-foot grid pattern across the manufacturing area o f the facility as described in the Phase I Supplemental RFI Work Plan. The CPT rig was equipped with an integrated electronic cone system. Cone soundings recorded during advancement o f the borings included cone bearing and sleeve friction. Readings were taken at five centimeter intervals. The CPT interpretations were based on values o f tip, sleeve friction and pore pressure averaged over an interval of approximately 0.20 meters. The locations o f the CPT borings are depicted on Figure 3. 3.5 Deviations from the Work Plan Deviations from the Phase I Supplemental RFI Work Plan are as follows: ? The approved work plan did not specify surface water samples to be collected. However based on the lithologic/seepage face evaluation as well as analytical data, a potential data gap was identified with regard to potential discharge of shallow groundwater into the drainage channel. Therefore surface water samples were collected from the referenced channel. ? A risk evaluation and Environmental Indicator (El) questionnaire were proposed to be completed in the Phase I Supplemental RFI Work Plan. However based on data gaps identified during this investigation, the risk evaluation and El questionnaire were not completed. 3.6 Decontamination Procedures All CPT drilling equipment was decontaminated by high-pressure wash prior to use at each location. Rinse water from decontamination activities drained into a 55-gallon drum and was processed through the plant's wastewater treatment system. Sampling equipment that was not dedicated or disposable was decontaminated prior to use at each sampling location using the following four steps: ? Scrub with Alconox soap and potable water; ? Rinse with potable water; ? Rinse with deionized water; and ? Air dry. 3.7 Investigative Derived Waste Types of waste generated during the field investigation included purge water, decontamination water, and personal protective equipment (PPE). The management of all investigative derived waste was dictated by the Phase I Supplemental RFI Waste Management Plan (WMP) (November 2002). Tubing and PPE were placed in plastic garbage bags and deposited in a trash receptor at the site. Decontamination water was processed through the site wastewater treatment system. Purge water generated from Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC 13 investigation Report (revised) Field Investigation Summary monitor wells and piezometers were containerized in 55-gallon drums as specified in the WMP. All o f the drums were labeled "On Hold Pending Analyses" according to the WMP. Waste tracking sheets, completed for all of the drums and poly tank, contained the following information: container identification number, sample location, material description, container type, and generation date. A total of two drums o f purge/decon water were generated. All of the drums were characterized as non-hazardous based on evaluation o f the analytical data. Purge water generated as part of this investigation was dispensed to the site wastewater treatment plant. 3.8 Quality Assurance/Quality Control Program The purpose o f the RFI Quality Assurance (QA)/Quality Control (QC) Program was to ensure that collected data were both representative and valid. Data Quality Objectives (DQOs) enable the decision-maker to assess the level of certainty that can be attributed to environmental measurements. The Phase I Supplemental RFI Work Plan lists the following DQOs: accuracy, precision, completeness, representativeness, and comparability. To ensure the DQO for comparability was satisfied, all sampling activities followed the standard operating procedures described in Section 4.0 of the Phase I Supplemental RFI Work Plan (December, 2003). Each sample was documented at the time of collection by the investigator. The sample quantity, type (composite or grab), and sample location were recorded in the field logbook. Sample containers were labeled with sample identification numbers, the time and date o f collection, proposed laboratory analyses, and initials of the samplers. Prior to dispatch of the samples, chain-of-custody forms were completed and the sample-shipping cooler was secured with a custody seal. The quality and integrity of samples collected and analyzed during the investigation were monitored by routine preparation o f various QA/QC samples. Field program QA/QC samples included trip blanks, duplicates and equipment/rinsate blanks. ? Trip Rlanks - Trip blanks satisfy the DQO of accuracy, and consist of cleaned sample vials containing analyte-free water that have been pre-certified by analysis at the laboratory. Trip blanks accompanied every shipping cooler containing sample bottles specified for volatile organic compound (VOC) analysis to determine if cross-contamination occurred dining shipping. A total of three trip blanks were collected during the Phase I Supplemental RFI. ? Duplicates - Duplicate samples ensure precision and comparability o f results, and are collected in the same manner as routine analytical samples. By comparing the results of the duplicate and the original sample, the precision of the analytical method, sample matrix and collection technique can be evaluated. A total of three field duplicates were taken over the course o f the Phase I Supplemental RFI, exceeding the minimum rate of one in every 20 for each appropriate type of matrix and parameter. ? Equipment Blanks - Equipment blanks satisfy the DQO o f accuracy, and are used to identify potential sources of cross-contamination. At the sample location, analyte-free water or deionized water was poured over or through the sample collection device, collected in a Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC investigation Report (revised) Field investigation Summary sample container, and preserved as appropriate. All blanks were handled, transported, and analyzed in the same manner as the actual field samples. A total of three equipment blanks were taken during over the course of the Phase I Supplemental RFI, exceeding the minimum rate of one in every 20 for each appropriate type of matrix and parameter. The quality and integrity of samples analyzed during the investigation were monitored by routine analysis of various QA/QC samples in the laboratory. Laboratory QA/QC samples included Matrix Spike/Matrix Spike Duplicate (MS/MSD) samples and method blanks. ? MS/MSD - To ensure the DQO o f precision is met, the laboratory analyzed MS/MSD samples. MS/MSD samples are spiked with a known concentration o f target analytes(s) to determine if bias exists in a given analytical method. ? Method Blanks - Method blanks satisfy the DQO of accuracy, and are used to document contamination resulting from the analytical process. In the laboratory, analyte-free water or deionized water is carried through the complete sample preparation and analytical procedure. Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC 15 investigation Report (revised) Results of Phase I Supplemental RFI Investigation 4.0 RESULTS OF PHASE I SUPPLEMENTAL RFI INVESTIGATION 4.1 Results This section presents the analytical results of the Phase I Supplemental RFI sampling efforts. Historical descriptions of each unit are provided along with the objective and scope of the investigation. Analytical data are summarized in tables referenced in the text. Field parameters are summarized in Table 3. Laboratory analytical data reports are presented in their entirety in Appendix B. This section begins with a discussion of the QA/QC results and is followed by a description o f the screening process developed for the analytical data. A discussion of the analytical results for each unit follows. 4.2 QA/QC Analytical Results The usability o f RFI analytical data was evaluated for compliance with the DQOs set forth in the Phase I Supplemental RFI Work Plan (November 2001). This section evaluates QA/QC data obtained during the Phase I Supplemental RFI. 4.2.1 QA/QC Sample Blanks Analytical samples were screened against blanks to identity potential sources o f cross contamination in the sample collection and analytical process. Guidance for interpreting inorganic blank contamination was taken from the USEPA National Functional Guidelinesfo r Inorganic Data Review (USEPA, 1994). Guidance for interpreting organic blank contamination was taken from the USEPA National Functional Guidelines fo r Organic Data Review (USEPA, 1999): ? Equipment Blanks: There were no detections in the blanks associated with the samples collected for the Phase I Supplemental RFI. ? Trip Blanks: There were no detections in the blanks associated with the samples collected for the Phase I Supplemental RFI. ? Method Blanks: There were no detections in the blanks associated with the samples collected for the Phase I Supplemental RFI. 4.2.2 Duplicates Groundwater Samples: Two duplicate pairs were collected to represent the groundwater matrix. Overall, a comparison of the constituent concentrations present in both the primary and duplicate samples demonstrated good precision. Overall, a comparison o f the constituent concentrations present in both the primary and duplicate samples demonstrated good precision. Surface Water Samples: One duplicate pair was collected to represent the surface water matrix. Overall, a comparison of the constituent concentrations present in both the primary and duplicate Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC 16 investigation Report (revised) Results of Phase I Supplemental RFI Investigation samples demonstrated good precision. Overall, a comparison of the constituent concentrations present in both the primary and duplicate samples demonstrated good precision. 4.3 Analytical Screening Process 4.3.1 Groundwater Analytical Screening Process If a constituent was detected in groundwater, all method blanks were first reviewed for the presence of that compound. Constituents detected below method blank limits were eliminated from the screening process. Detected inorganic and organic constituents in groundwater samples were first compared to concentrations detected in upgradient monitor wells. The detected concentrations were then compared to the drinking water pathway. For the drinking water pathway, detected constituents were compared to the NCDENR 2L groundwater quality standards. If a NCDENR 2L groundwater quality standard was not available, the detected constituent was compared to the EPA Region IX Preliminary Remediation Goal (PRG) for tap water criteria. If the detected constituent is less than the applicable screening value, it was considered a nonexceedance. If the detected constituent exceeded the applicable screening value or if a screening value was not available, the constituent was considered an exceedance and warranted further evaluation. 4.4 SWMU and AOC Analytical Results 4.4.1 SWMU 6 - Process Sewers Date of Operation: 1972 to present Unit Characterization SWMU 6 is a system of underground sewer pipes, manholes, and sumps, which convey process wastewater from the main plant areas to the site's WWTP system. Plant personnel and site sewer maps indicate that the pipes are constructed of reinforced concrete, vitrified clay or steel. The common sump is part of the process sewer system located in the Nafion area (Figure 7). The sump was initially constructed of concrete with a poly liner. A double walled stainless steel vault was later installed due to integrity problems with the poly liner. In October 2000, a new double walled stainless steel vault was installed during a plant maintenance shutdown. This sump receives waste from the Nafion process, which includes process wastewater, cooling water, and steam condensate from the various manufacturing units. The Nafion internal process sewers normally contain only cooling water or steam condensate. During floor washing, small quantities o f process materials and lube oils may be washed into the sumps. Internal sumps within the Nafion area are tested for pH and the presence of a heavy fluorocarbon liquid phase. If pH is not neutral or if a fluorocarbon phase is detected, the sump material is drummed for off-site disposal. It also receives low pH process wastewater from the resins process and the RSU (rearranged sultone unit) process located in the Nafion area. Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC 17 investigation Report (revised) Results of Phase I Supplemental RFI Investigation Supplemental Phase I Objectives and Scope The objectives for the Phase I Supplemental RFI at SWMU 6 were to: ? Further characterize groundwater quality downgradient o f the common sump by sampling monitor wells (NAF-01 through NAF-04 and Piezometers PZ-02 through PZ-06). ? Evaluate the potential of shallow groundwater discharging into the drainage channel located northeast of the unit by collecting four surface samples at locations along the drainage channel. Analytical Results Groundwater Samples Groundwater samples were analyzed for volatile organic compounds by SW-846 Method 8260B, for methanol by SW-846 Modified Method 8015B and for semi-volatile organic compounds by SW-846 Method 8270C. In addition, the samples were analyzed for chloride and fluoride by EPA Method 300.0. Also groundwater samples collected from monitor wells NAF-01 through NAF-04 were analyzed for C-8. A complete list of organic analytes are presented in Table 1 of the December 11, 2003 Revised RCRA Phase I Supplemental Work Plan. The analytical data is also summarized in Table 3. One inorganic compound, chloride, was detected in the groundwater sample collected from upgradient monitor well NAF-01. Two organic compounds (chloroform and C-8) were detected above the MDL in the sample collected from upgradient monitor well NAF-01. Two inorganic compounds, fluoride and chloride, were detected in groundwater samples collected from the three downgradient monitor wells (NAF-02 through NAF-04) and piezometers PZ-02 through PZ-04 and PZ-06 above the respective MDL. No organic compounds were detected above the MDL in groundwater samples collected from PZ-03 and PZ-05. Two organic compounds (bis(2-ethylhexyl)phthalate and di-nbuytl phthalate) were detected above the MDL in the groundwater sample collected from downgradient piezometer PZ-02. One organic compound (C-8) was detected above the MDL in the groundwater sample collected from down gradient monitor well NAF-02. Eight organic compounds (1,1trichloethane, 1,1-dichloroethene, 1,2-dichloropropane, chloroform, trans-1,2dichloroethene, tetrachloroethene, methylene chloride, C-8 and trichloroethene) were detected in the groundwater sample collected in downgradient monitor well NAF-03 at or slightly above the laboratory method detection limits (MDL). Four organic constituents (1,1-dichloroethene, dichlorofluoromethane, C-8, and methylene chloride) were detected above the MDL in the groundwater sample collected from monitor well NAF-04. Six organic compounds (1,1-dichloroethene, 1,2-dichloroethane, acetone, dichlorofluoromethane, bis(2-ethylhexyl)phthalate and di-n-buytl phthalate) were detected above the MDL in the groundwater sample collected from downgradient piezometer PZ-04. Two organic compounds (chloroform and methylene chloride) were detected above the MDL in the groundwater sample collected from downgradient piezometer PZ-06. Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC investigation Report (revised) Results of Phase i Supplemental RFI Investigation O f the detected inorganic constituents, the fluoride concentrations detected in PZ-02, PZ06, NAF-02, NAF-03 and NAF-04 exceeded the DENR 2L groundwater quality standard of 2.0 ug/1. O f the detected organic constituents, the chloroform concentrations in groundwater samples collected from NAF-01, PZ-06 and NAF-03 exceeded the NCDENR 2L groundwater quality standard of 0.19 ug/1. The methylene chloride concentrations detected in groundwater samples collected from PZ-06, NAF-02 and NAF-04 exceeded the NCDENR 2L groundwater quality standard of 0.005 ug/1. The concentrations of 1,2dichloropropane, tetrachloroethene and trichloroethene exceed the respective NCDENR 2L groundwater quality standards o f 0.56 ug/1, 0.7 ug/1 and 2.8 ug/1 in NAF-03. The concentrations o f bis(2-ethylhexyl)phthalate in PZ-02 and PZ-04 exceeded the NCDENR groundwater quality standard of 3.0 ug/1. Figure 7 presents the groundwater exceedances and associated sampling points. Surface Water Samples Surface water samples were analyzed for volatile organic compounds by SW-846 Method 8260B, for methanol by SW-846 Modified Method 8015B and for semi-volatile organic compounds by SW-846 Method 8270C. In addition, the samples were analyzed for chloride and fluoride by EPA Method 300.0. Figure 8 presents the analytical data and associated surface water sample locations. The analytical data is also summarized in Table 4. Two inorganic compounds (fluoride and chloride) were detected at similar concentrations in each of the up and downgradient surface water samples. No organic compounds were detected above the MDL in the collected surface water samples. Detected constituents were below the respective NCDENR 2B surface water quality standards. 4.4.2 Fire Training Area Unit Characterization Date of Operation: Unknown (Out of Service) The training area consisted o f a 3 foot by 3 foot metal pan, which was located on the ground and surrounded by a soil and gravel berm. The location of the fire training area is shown in Figure 4. The total bermed area was approximately 15 feet by 15 feet. Combustible materials (non-process materials) were placed in the metal pan and diesel fuel was used to start the combustion process. Trainees would then practice extinguishing the fires. The fire training area was closed approximately 15 years ago by removing the metal fire pan and pushing the gravel berms into the interior o f the training area. Contaminated soil was excavated during road construction as described in the Excavation Sampling Report, dated November 8, 2001. Phase I Objectives and Scope The objectives for the Phase I Supplemental RFI at the Former Fire Training Area were to: ? Further characterize groundwater quality downgradient of the Former Fire Training Area. Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC 19 investigation Report (revised) Results of Phase I Supplemental RFI Investigation Analytical Results Groundwater samples were analyzed for volatile organic compounds by SW-846 Method 8260B, for PAHs SW-846 Method 8270C and total lead chromium and nickel by SW846 Method 601OB. A complete list o f organic analytes are presented in Table 2 o f the April 2003 Phase I Supplemental RFI Work Plan. The analytical data is also summarized in Table 5. One inorganic constituent, lead, was detected above the MDL in the sampled monitor wells. No other organic or inorganic compounds were detected above the MDL in the collected groundwater samples. The lead concentrations detected in the upgradient monitor well FTA-01 and downgradient monitor well FTA-03 exceeded the NCDENR 2L groundwater quality standard of 15 ug/1. Figure 9 presents the groundwater exceedances and associated monitor wells. Fayetteville Supp RFI-I Report-doc Nov. 12, 04 Charlotte, NC 20 investigation Report (revised) Significance of Results 5.0 SIGNIFICANCE OF RESULTS This section provides a discussion of the significance o f the data collected as part of the Phase I Supplemental RFI with respect to the revised site conceptual model and the prioritization process documented in the CS Report dated May 3,1999. 5.1 Revised Site Conceptual Model 5.1.1 Topography The facility topography is relatively flat within the developed portion of the site. The topographic relief increases outside the developed area of the site towards the Cape Fear River. Topographic relief from the plant to the river is approximately 50 feet. This physical setting would result in a relatively flat water table gradient between the plant and the river. 5.1.2 Lithology/Hydrogeology Lithology The site is underlain by a fine to medium grained sand unit with interbedded silt/clay lenses. This unit is underlain by a stiff clay/clayey silt layer. The depth to the top o f the clay layer is approximately 15 to 18 feet below the ground surface. Thirty-one CPT borings were advanced during the Phase I Supplemental RFI to evaluate the presence of the clay layer throughout the developed portion of the site. The clay/clayey silt layer was observed in 26 o f 31 CPT borings. The clay layer is continuous throughout the SWMUs/AOC investigated during the Phase I RFI and Phase I Supplemental RFI. Cross sections were generated to depict the clay layer observed during the CPT investigations. The clay layer becomes thinner moving west across the site and was not encountered in those borings completed in the powerhouse, administration and Butacite manufacturing areas. Figure 9 presents the cross-section locations. Figures 10,11 and 12 present cross sections A-A' through C-C', respectively. Figure 13 depicts a contour map of the top of the clay/clayey silt layer. CPT borings were advanced through the clay layer at several locations outside of the manufacturing area. The thickness of the clay layer ranged from approximately three feet (boring C-4) to approximately 19 feet borings (D-3 and D-5). Generally, The clay/clayey silt layer thickness increases towards the eastern portion of the facility. Figure 14 depicts an isopach map of the clay/clayey silt layer based on data collected from the CPT borings. A visual inspection for the clay/clayey silt layer was conducted along the drainage channel located to the northeast of SWMU 6 (common sump) and along the slopes leading to the Cape Fear River. The clay/clayey silt layer was observed in the channel bottom in the portion of the channel located immediately northeast o f PZ-2 to be approximately 10 to 12 feet thick in the channel banks. The area o f the channel where the Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC 21 investigation Report (revised) Significance of Results clay/clay silt layer was observed also coincided to an area of the channel where seepage faces were observed. Hydrogeology An unconfined aquifer consisting o f mainly fine to medium grained sand with interbedded clay/silt lenses underlies the site. This shallow surficial aquifer is situated on a stiff clay/clayey silt layer that was observed underlying the investigated SWMUs and AOC. Depth to groundwater at the time o f the Phase I Supplemental RFI investigation ranged from approximately six feet below the ground surface in the vicinity of SWMU 6 to approximately 18 feet below the ground surface in the vicinity of SWMU 9 and the Former Fire Training Area. Site wide recharge o f the surficial aquifer is expected to be from localized infiltration o f rainwater. Fluctuation of the shallow surficial aquifer saturated thickness is expected to coincide with the amount of rainfall infiltration and to be significant at times depending on the rainfall amount. This is evidenced by the presence of gleyed soils extending approximately two to three feet above the saturated zone as observed in borings installed in the vicinity of SWMU 6. Figure 15 depicts the site-wide shallow groundwater potentiometric surface. It appears that direction of groundwater flow in the surficial aquifer is controlled by the structure (e.g., dip) o f the underlying clay/clayey silt layer. This is clearly evident in the areas where a higher concentration of monitor wells/piezometers are present (e.g., SWMU 6, SWMU 9 and the Former Fire Training Area). Groundwater flow in the vicinity of SWMU 9 may also be influenced by the presence o f a channel located to the south/southwest of SWMU 9. This geomorphic feature may be a discharge point for shallow groundwater in this area of the site. Groundwater flow in the vicinity o f SWMU 6 flows towards the north/northeast against the direction o f the clay/clayey silt layer dip. This anomaly in flow direction in the vicinity SWMU 6 may be the result of a shallow ground water divide west of SWMU 6 possibly caused by two unlined river water holding basins recharging the shallow aquifer. Water from the Cape Fear River is pumped to these basins where sediment is allowed to settle prior to the water being used in the production process. Evidence of this recharge can be seen by water levels measured in PZ-11 and NAF-01. The possible mounding effect of the holding basins may generate enough head to override the shallow dip of the clay/clayey silt layer and cause groundwater flow to trend towards the northeast. Given the dip o f the clay/clayey silt layer and groundwater flow trend to the west of the river water holding ponds the groundwater gradient would be relatively unaffected by the recharge. The hydraulic gradient in the vicinity of SWMU 6 is shown to be relatively flat and increases towards the northeast portion o f the area against the direction o f the clay/clayey silt layer dip. The water level measured in PZ-2 is suspect considering the dramatic increase in gradient observed in this portion of the site relative to the shallow clay/clayey silt layer dip as well as the opposed direction of the dip from that of groundwater flow. Additionally this water level measurement may be accentuated due to the screen interval o f the piezometer being completed within the clay layer. Given the depth to groundwater measured in sampling points in the vicinity of the Nation wastewater channel, the channel is an unlikely discharge point for shallow Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC 22 investigation Report (revised) Significance of Results groundwater in this portion of the site. A visual inspection of the drainage channel located to the northeast of SWMU 6 indicated seepage faces present in the bank o f the channel immediately northeast o f the PZ-02. As stated previously, the area where the seepage faces were observed coincides with the outcropping of the clay/clayey silt layer, determine to be the lower boundary of the surficial aquifer, in the drainage channel bottom. 5.1.3 Contaminant Distribution Former Fire Training Area Lead was the only constituent detected above the NCDENR 2L groundwater quality standards in groundwater samples collected from monitor wells installed in the vicinity o f the Former Fire Training Area. The concentration of lead detected in upgradient monitor well FTA-01 was slightly greater than the concentration o f lead detected in downgradient monitor well FTA-03. The elevated lead concentrations are believed to be caused by sediments in the well becoming agitated during sampling with bailers and becoming incorporated in the groundwater sample. Thus elevated lead concentrations are believed to be associated with the sediments incorporated in the groundwater sample and naturally occurring. During the previous sampling event using low flow sampling techniques, only one lead concentration in groundwater samples collected from this unit was slightly above the NCDENR 2L groundwater quality standard. Additionally, detected lead concentrations are similar to concentrations of lead detected in groundwater samples collected from monitor wells located in the vicinity o f SWMU 9. SWMU 6 (Common Sump) Several organic constituents were detected at or above the NCDENR 2L groundwater quality standards in groundwater samples collected from area monitor wells and piezometers. A majority o f constituents detected above the NCDENR 2L (i.e., 1,2dichloropropane, chloroform, tetrachloroethene, and trichloroethene) were detected below the respective laboratory PQL. Methylene chloride is the only organic constituent detected both above the laboratory PQL and DENR 2L groundwater quality standard and thus is identified as a constituent o f concern (COC). Organic constituents detected in groundwater samples collected from SWMU 6 were not detected in the surface water samples. C-8 was not analyzed for in the surface water samples and is considered a data gap, which is addressed in Section 6.0 o f this report. Detections o f C-8 were observed in monitor wells NAF-01 through NAF-04. A screening criteria was not available using the screening matrix presented in the approved Phase I Supplemental Work Plan. However as discussed in the December 11,2003 Response to Comments Letter from DuPont, a risk-based drinking water concentration of 150 ug/1 has been established by the C-8 Assessment of Toxicity Team (CATT).1 The 1The CATT was a scientific team formed pursuant to a Consent Order amongst the West Virginia Department o f Environmental Protection ( WVDEP), the West Virginia Department o f Health and Human Resources (WVDHHR), and DuPont. CATT members represented the following entities: WVDEP, WVDHHR, EPA (specifically, Headquarters - Office o f Pollution Prevention and Toxics, Region 3 and the Office o f Research and Development), Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC 23 investigation Report (revised) Significance of Results highest concentration of C-8 detected in the monitor wells (NAF-01 through NAF-04) is orders o f magnitude below this risk-based drinking water maximum concentration. Toxicology Excellence for Risk Assessment (TERA) and DuPont. The Ohio Environmental Protection Agency participated as an observer. Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC 24 investigation Report (revised) Conclusions and Recommendations 6.0 CONCLUSIONS AND RECOMMENDATIONS The purpose o f the Phase I Supplemental RFI was to further characterize potential releases to the environment from one SWMU and one AOC identified in the Phase I RFI Report as having unknown or low priority exposure pathways with respect to contaminant type; concentration and migration potential; strengthen the site conceptual model; and identify SWMUs/AOCs requiring further evaluation. Section 6.1 presents the conclusions based upon data obtained during the Phase I Supplemental RFI. Section 6.2 presents recommendations for future investigation at the Fayetteville Works facility. 6.1 Conclusions Based on the data collected during the Phase I Supplemental RFI and the revised SCM, the following conclusions are offered: SWMU 6 ? Only one organic (methylene chloride) and one inorganic (chloride) compound were detected in monitor wells downgradient of the SWMU 6 (common sump) above the respective PQL and NCDENR 2L groundwater quality standards. ? Although a NCDENR 2L groundwater standard is not available for C-8, the low levels of C-8 detected in the groundwater samples collected from monitor wells present in the vicinity of SWMU 6 (common sump) are well below recognized risk-based drinking water standards. Former Fire training Area ? The lead detected in the groundwater samples appears to be naturally occurring. No other constituents were detected above the DENR 2L groundwater quality standards. Site Conceptual Model ? Potential vertical migration of shallow surficial groundwater at the site is retarded by the presence of a continuous stiff clay/clayey silt layer underlying the investigated areas. ? Groundwater flow in the surficial aquifer is controlled by the topography o f the underlying clay/clayey silt layer except in the vicinity of SWMU 6. ? A localized groundwater mound potentially exists in the vicinity of the river water holding basins which may cause groundwater flow in the vicinity of SWMU 6 (common sump) to flow against the direction of the clay/clayey silt layer dip. ? Seepage faces were observed in a portion o f the drainage channel located to the northeast of the SWMU 6 (common sump). ? Data collected during the Phase I Supplemental RFI as well as historical data in conjunction with existing administrative controls at the site indicates that no immediate threat to human health or the environment exists as a result o f operations at the site. Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC 25 investigation Report (revised) Conclusions and Recommendations 6.2 Recommendations and Path Forward Based upon the conclusions presented above, the following recommendations are offered to fill data gaps in order to complete RFI activities: ? Further characterize groundwater quality downgradient of SWMU 6 (common sump) by installing the monitor wells depicted in Figure 16. ? Further characterize the potential for a groundwater mound in the vicinity o f the river water holding basins by installing piezometers depicted in Figure 16. ? Further characterize surface water quality in the drainage channel at the same locations as previously collected and analyze the samples for C-8. ? Further characterize shallow groundwater quality southeast o f SWMU 9 by installing one monitor well downgradient of SWMU 9 A/B as depicted in Figure 16. ? Conduct a formal risk evaluation to support remedial decision-making. ? Submit a final RFI Report. In order to minimize correspondences between DuPont and NCDENR, DuPont proposes to implement the above recommendations utilizing the Data Management Plan, Project Management Plans as well as methods and procedures presented in previously approved work plans. Fayetteville Supp RFI-I Report.doc Nov. 12, 04 Charlotte, NC 26 investigation Report (revised) References 7.0 REFERENCES DERS, 1996, RCRA Facility Assessment, Fayetteville Works, Fayetteville, North Carolina, December 1996. DuPont, 1999, Confirmatory Sampling Supplemental Report, DuPont Fayetteville Works, North Carolina, December 1999 DuPont, 1999, Confirmatory Sampling Report, DuPont Fayetteville Works, North Carolina, May 1999 DuPont, 2001, Phase IR FI Work Plan, DuPont Fayetteville Works, North Carolina, June 2001 NCDENR, 1997, RCRA Part B Permit, DuPont Fayetteville Works, Fayetteville, North Carolina, December 1997 NCDENR Ground Water Section, Groundwater Section guidelines for the Investigation and Remediation o f soil and groundwater, July 2000 Fetter, C.W., 1980, Applied Hydrogeology, Charles E. Merrill Publishing Co., Columbus Ohio. p. 75. Heath, R. C., 1980, Basic Elements of Groundwater Hydrology with Reference to Conditions in North Carolina, United States Geological Survey Water Resources Investigations, Open-file Report No. 80-44. Horton, J. W., and V. A. Zullo, editors, 1991, The Geology of the Carolinas, Carolina Geological Society, Fiftieth Anniversary Volume, The University of Tennessee Press, Knoxville. North Carolina Department o f Environment, Health, and Natural Resources (NCDENR), 1995, Standards of Construction: Wells Other Than Water Supply, T15A:02C.0108. August 29, 1995. North Carolina Department of Environment, Health, and Natural Resources (NCDENR), 1995, Guidance for the Use o f RCRA National Corrective Action Prioritization System (NCAPS) in North Carolina. August 29,1995. USEPA, 1986, Test Methods for Evaluating Solid Waste, Physical/Chemical Methods, SW-846 Third September 1986, as amended by Update I, July 1992. Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC investigation Report (revised) References USEPA, 1989b, Interim Final RFI (RFI) Guidance, Volume I of IV; Section 8, Health and Environmental Assessment, OSWER Directive 9502.00-6D, EPA 530/SW89-031. USEPA, 1991a, EPA Region IV Standard Operating Procedures and Quality Assurance Manual, February 1993. USEPA, 1992a, RCRA Ground-Water Monitoring: Draft Technical Guidance. November 1992. Winner, M. D., 1977, Groundwater Resources Along the Blue Ridge Parkway, North Carolina, United States Geological Survey, Groundwater Division, Raleigh, NC, 1977. Fayetteville Supp RFI-I Reportdoc Nov. 12, 04 Charlotte, NC 28 TABLES Table 1 Groundwater Level Elevations Phase I Supplemental RFI DuPont Fayetteville Works Sample NAF-01 NAF-02 NAF-03 NAF-04 FTA-01 FTA-02 FTA-03 PZ-01 PZ-02 PZ-04 PZ-05 PZ-06 PZ-07 PZ-08 PZ-09 PZ-10 PZ-11 PZ-12 PZ-13 PZ-14 PZ-15 PZ-16 PZ-17 PZ-18 MW-1S MW-2S MW-7S MW-8S MW-9S MW-12S TOC Elevation 149.66 150.31 150.44 148.10 150.63 150.28 151.08 148.80 145.08 148.87 148.52 149.22 148.55 148.78 147.03 148.66 151.03 150.91 149.20 148.38 148.79 149.11 150.08 150.83 149.93 149.91 147.47 146.48 154.39 152.06 Depth to Water 7.61 8.90 9.62 6.54 16.58 17.51 17.48 17.34 11.10 7.59 7.38 8.88 6.98 14.86 14.44 14.69 11.44 19.31 11.23 10.53 13.26 13.46 dry 20.53 18.83 19.07 10.11 11.35 21.30 19.84 Water Elevation 142.05 141.41 140.82 141.56 134.05 132.77 133.60 131.46 133.98 141.28 141.14 140.34 141.57 133.92 132.59 133.97 139.59 131.60 137.97 137.85 135.53 135.65 dry 130.30 131.10 130.84 137.36 135.13 133.09 132.22 NOTES: TOC = Top of Casing All measurements presented in feet Well Numoer FTA-01 FTA-02 FTA-03 NAF-01 NAF-02 NAF-03 NAF-04 PZ-01 PZ-02 PZ-03 PZ-04 PZ-05 PZ-06 PZ-07 PZ-11 PZ-12 PZ-13 PZ-14 PZ-15 PZ-16 PZ-17 PZ-18 Table 2 Piezometer and Monitoring Well Construction Details Total Drilled Depth (ft) 22.0 21.5 22.0 15.0 15.0 15.0 15.0 20.0 20.0 20.0 20.0 20.0 16.0 16.0 20.0 20.1 12.1 14.0 15.2 14.2 26.1 24.1 Phase 1Supplemental RFI DuPont Fayetteville Works Screened Interval Filter Pack Well Depth (ft) Depth (ft) 22.0 12.0-22.0 10.0-22.0 21.5 11.5-21.5 9.5-11.5 22.0 12.0-22.0 10.0-22.0 15.0 5.0-15.0 4.0-15.0 15.0 5.0-15.0 4.0-15.0 15.0 5.0-15.0 4.0-15.0 15.0 5.0-15.0 4.0-15.0 20.0 15.0-20.0 8.0-20.0 20.0 15.0-20.0 4.0-20.0 20.0 15.0-20.0 2.0-20.0 20.0 15.0-20.0 2.0-20.0 20.0 15.0-20.0 13.0-20.0 16.0 11.0-16.0 9.0-16.0 16.0 11.0-16.0 9.0-16.0 20.0 15-20 15-20 20.1 15.1-20.1 15.1-20.1 12.1 7.1-12.1 7.1-12.1 14.0 9.0-14.0 9.0-14.0 15.2 10.2-15.2 10.2-15.2 14.2 9.2-14.2 9.2-14.2 26.1 21.1-26.1 21.1-26.1 24.1 19.1-24.1 19.1-24.1 Benlomte Seal Interval Dcptn (ft) 7.6-10.0 7.5-11.5 8.0-10.0 2.0-4.0 2.0-4.0 2.04.0 2.0-4.0 5.0-8.0 2.0-4.0 0.5-2.0 0.5-2.0 11.0-13.0 7.0-9.0 7.0-9.0 12-15 12.1-15.1 4.1-7.1 6.0-9.0 7.2-10.2 6.2-9.2 18.1-21.1 16.1-19.1 Grout Interval 0.0-7.0 0.0-7.5 0.0-8.0 0.0-2.0 0.0-2.0 0.0-2.0 0.0-2.0 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA Notes: NA = not applicable ft = feet below ground surface Sample NAF-01 NAF-02 NAF-03 NAF-04 FTA-01 FTA-02 FTA-03 PZ-02 PZ-03 PZ-04 PZ-05 PZ-06 Table 3 Water Quality Parameters Phase I Supplemental RFI DuPont Fayetteville Works DATE 02/04/04 02/04/04 02/04/04 02/04/04 02/03/04 02/03/04 02/03/04 02/04/04 02/04/04 02/04/04 02/04/04 02/04/04 TIME 930 1220 1055 1255 1545 1502 1420 1152 1315 1345 1440 1510 pH 5.12 9.11 NM 8.27 5.64 5.98 6.08 NM NM NM 7.13 7.93 TEMP (C) 10.91 12.63 NM 13.92 14.84 15.46 17.21 NM NM NM 14.81 11.48 SPECIFIC TURBIDITY DISSOLVED COND OXYGEN ODOR COLOR Cemmentb (mS/cm) (NTU) imq/l) 0.178 161.0 4.20 none slightly cloudy 1.270 NM >999.0 NM 12.11 NM none none brown Parameters not collected due to lowwell slightly cloudy volume. 0.185 >999.0 3.50 none brown 0.063 >999.0 10.04 none brown 0.089 802.0 6.93 none cloudy 0.086 NM NM NM 12.7 NM NM NM 2.72 NM NM NM none none none none clear Parameters not collected due to low well slightly cloudy volume. Parameters not collected due to low well slightly cloudy volume. Parameters not collected due to low well slightly cloudy volume. 0.044 >999.0 4.34 none brown 0.310 >999.0 0.00 none brown NOTE: C = degrees Celsius mS/cm = mllliSeimens per centimeter NTU = National Turbidity Unit mg/l = milligrams per liter NM = Not Measured Table 4 SWMU 6 Groundwater Detections Phase I Supplemental RFI DuPont Fayetteville Works Sample ID SWMU6-NAF-01 S W M U 6-N A F-02 S W M U 6-N A F-03 SW M U 6-N A F-04 S W M U 6-P Z-02 S W M U 6 -P Z -0 4 S W M U 6 -P Z -0 6 Date 2/4/2004 2/4/2004 2/4/2004 2/4/2004 2/4/2004 2/4/2004 2/4/2004 Consitiuent CHLORIDE C-8 CHLOROFORM CHLORIDE C-8 FLUORIDE 1,1,1-TRICHLOROETHANE 1,1-DICHLOROETHENE 1,2-DICHLOROPROPANE CHLORIDE C-8 CHLOROFORM FLUORIDE METHYLENE CHLORIDE TETRACHLOROETHYLENE T R A N S -1,2 -D IC H L O R O E T H E N E TRICHLOROETHENE 1,1-DICHLOROETHENE CHLORIDE C-8 DICHLORODIFLUOROMETHANE FLUORIDE METHYLENE CHLORIDE BIS(2-ETHYLHEXYL)PHTHALATE CHLORIDE DI-N-BUTYL PHTHALATE FLUORIDE 1,1-DICHLOROETHENE 1,2-DICHLOROETHANE ACETONE BIS(2-ETHYLHEXYL)PHTHALATE CHLORIDE DICHLORODIFLUOROMETHANE DI-N-BUTYL PHTHALATE FLUORIDE CHLORIDE CHLOROFORM FLUORIDE METHYLENE CHLORIDE Result 48200 0.0619 1J 191000 0.303 28900 1J 1J 1J 161000 1.53 11 7800 160 2J 2J 5J 2J 28500 0.0123 11 5000 210 23 184000 4J 10800 3J 2J 8J 6J 24600 17 3J 540 168000 3J 68700 25 Notes: All data presented in micrograms per liter J - Concentration detected between method detection limit and practical quantitation limit Table 5 Surface W ater Analytical Detections Phase I Supplemental RFI DuPont Fayetteville W orks Sample ID SW-01 S W -02 S W -03 S W -04 Date 4/8/2004 4/8/2004 4/8/2004 4/8/2004 Consitiuent Chloride Fluoride Chloride Fluoride Chloride Fluoride Chloride Fluoride Result 60500 <4 56800 1300 38600 850 38700 840 Table 6 Former Fire Training Area Groundwater Detections Phase i Supplemental RFI DuPont Fayetteville Works Sample ID FTA-01 FTA-02 FTA-03 Date 2/3/2004 2/3/2004 2/3/2004 Constituent LEAD LEAD LEAD Result 136 10.5 J 5T3 Notes: All data presented in micrograms per liter J - Concentration detected between method detection limit and practical quantitation limit FIGURES GAFavetvle<Gis/Proiect_figures/Suppl_nvest9ation/Report/topo.apr G:\Favetvle\Gi$\Pro|ecLfiflures\Suppl investlnation\RepQrt\swmuloc.apr (SWMU Locations) TITLE: CORPORATE REMEDIATION GROUP An Alliance between DuPont and URS Corporation - North Carolina 6324 Fairveiw Road Charlotte, N C 28210 Facility Layout with SWMU Locations DuPont Fayetteville Works DRAWN: DLH CHECKED: F IL E N A M E : swmuloc.apr APPROVED: DATE: 6/11/03 REVISION: 05/27/04 4 6:lFayetvte\(^VProject_rgures\SupplJn\restiflafon\Report\BorJoc_inap.apf (Boring location Map) Legend & 9 9 250 C P T Boring Location Monitoring W ell P iezom eter 0 250 500 Feet (flO W ti O C O RPO R ATE REM EDIATIO N G RO UP A n A llian ce b etw een D u P o n t a n d U R S C orp o ratio n - N o rth C aro lin a 6324 Fa/rveiw Road Charlotte, NC 28210 TITLE: Boring Location Map DuPont Fayetteville Works DRAWN: DLH CHECKED; FILE NAME BorJoc_map.apr APPROVED: DATE 0 5 /2 4 /0 4 REVISION: 0 5 /2 5 /0 4 g:\fayetole\gis\projeetJigures\suppUnvestigation\report\nafion_pot_rnap.apr (SWMU 6 Potenliomelric Map) G:\Fayetvle\Gis\ProiecLfigures\SupplJnvestigation\Report\ffla_pot_nnap.apr (Former Fire Training Area Potentiometrie Map) * O CORPORATE REMEDIATION GROUP An Alliance between DuPont and URS Corporation - North Carolina 6324 Fairvefw Road Chadotte, NC 28210 TITLE: Former Fire Training Area Potentiometrie Map DuPont Fayetteville Works DLH CHECKED: NS FILE NAME: ffta_p o L m ap .ap r 08/20/03 "R E V IS IO N : 05/24/04 Sample Date Analyte Result Unit Screening Type PZ-02 20040204 BIS(2-ETHYLHEXYL)PHTHALATE 23 ug/L NC2L PZ-02 20040204 FLUORIDE 10800 ug/L NC2L A PZ-02 Sampla Date Analyte Result Unit Screening Type PZ-06 PZ-06 PZ-06 20040204 CHLOROFORM 3 J ug/L NC2L 20040204 FLUORIDE 68700 ug/L NC2L 20040204 METHYLENE CHLORIDE 25 ug/L NC2L 1 Sample Date Analyte Result Unit Screening Type NAF-02 20040204 FLUORIDE 28900 ug/L NC2L NAF-02 20040204 C-8 0.303 ug/L N/A g:\fayelvle\gis\projeclJigures\supplJnvestigation\w orkplan\revisedJlgures\nafionjBw exce6d.apr (SW M U 6 G W Exceedances Map) Semaie Date Analyte Result Unit Screening Type NAF-01 20040204 CHLOROFORM 1 J ug/L NC2L NAF-01 20040204 C-8 0.0619 ug/L N/A PZ-07 (ND) Il I I N t 7 1 NAFION MANUFACTURING BLDG. rrff TPT TITLE: CORPORATE REMEDIATION GROUP An Alliance between DuPont and URS Corporation - North Carolina 6 3 2 4 Pairveiw Road Charlotte, N C 28210 SWMU 6 Groundwater Exceedances February, 2004 DuPont Fayetteville Works Sample Date Analyte Result Unit Screening Type NAF-03 NAF-03 NAF-03 NAF-03 NAF-03 NAF-03 NAF-03 20040204 20040204 20040204 20040204 20040204 20040204 20040204 1,2-DICHLOROPROPANE CHLOROFORM FLUORIDE METHYLENE CHLORIDE TETRACHLOROETHYLENE TRICHLOROETHENE C-8 1J 11 7800 160 2J 5J 1.530 ug/L ug/L ug/L ug/L ug/L ug/L ug/L NC2L NC2L NC2L NC2L NC2L NC2L N/A a s n r PZ-03 Sample Date Analyte Result Unit Screening Type NAF-04 20040204 FLUORIDE 5000 ug/L NC2L NAF-04 20040204 METHYLENE CHLORIDE 210 ug/L NC2L NAF-04 20040204 C-8 0.123 ug/L N/A Sample Date Analyte Result Unit Screening Type PZ-04 20040204 1,2-DICHLOROETHANE 2J PZ-04 20040204 BIS(2-ETHYLHEXYL)PHTHALATE 6 J ug/L NC2L ug/L NC2L ND 50 Legend Monitoring Wells Piezometers Common Sump No Detection 50 100 Feet DRAWN: DLH CHECKED: NS F IL E N A M E : nationjgwexceed.apr APPROVED: DATE 08/20/03 REVISION: 05/24/04 - '' Sample ate Analyte Results SWW --U011 20040408 Chloride 60500 Sample Date Analyte Results Units SW-02 20040408 Fluoride 1300 ug/l SW-02 20040408 Chloride 56800 ug/l G:\Favetvle\Gls\Prolect flgurestSuppl investlgatlonXReporftsw loc map.apr (Surface Water Detections Map) TITLE: CORPORATE REMEDIATION GROUP An Alliance between DuPont and URS Corporation - North Carolina 63 2 4 Falrveiw Road Charlotte, N C 28210 Surface W ater Detections Map DuPont Fayetteville Works q PZ-02 * O * A/ 125 -0- Legend X Monitoring Well Piezometer Surface Water Sample Channel Building Common Sump (SWMU 6) 125 250 Feet DRAWN: DLH CHECKED: APPROVED: DATE 05/18/04 R LE NAME: s w jo c jn a p .a p r REVISION: 05/24/04 PROJECT NO.: FIGURE NO.: 7  < I i FTA-01 PZ-08 (ND) Samplejd Date Analyte Result Unit Screenlng_ FTA-01 20040203 LEAD 136 ug/L NC2L I I G:\Fayetvle\Gis\Project_flgures\SupplJnvesllgatlon\Report\fftajw_exceds.apr (Former Training Afea GW Exceedances) (ND) Samplejd Date Analyte Result Unit Screening^ FTA-03 20040203 LEAD 51.5 ug/L NC2L FTA-03 . PZ-10 (ND) & O CORPORATE REMEDIATION GROUP AnAlliance between DuPont and URS Corporation - North Carolina 6 3 2 4 Fairveiw Road Charlotte, N C 28210 TITLE: Former Fire Training Area Groundwater Exceedances February 29, 2004 DuPont Fayetteville Works r Legend * Monitoring Well Piezometer ND No Detection Building 25 0 25 DRAWN: DLH CHECKED: F IL E N A M E : ffta_ gw _e xced s.a pr APPROVED: DATE 08/20/03 REVISION: 05/25/04 50 Feet y PROJECT NO.: FIGURE NO.: 00 4 G:\Fayetvle\Gis\Proiect_figures\Suppl_investigation\Report\xsectJoc_map.apr (Cross-Section Location Map) C O R P O R A T E R E M E D IA T IO N G R O U P AnAlliance between DuPontand URS Corporation - North Carolina 6324 Falrveiw Road Charlotte, NC 28210 TITLE: Cross-Section Location Map DuPont Fayetteville Works DRAWN: DLH CHECKED: FILE NAME: xsect_.loc_map.apr APPROVED: DATE: 05/18/04 REVISION: 05/25/04 PROJECT NO.: FIGURE NO.: 9 WEST GRAPHIC SYMBOLS vrzn Clay/Sllty Clay/ v&ZA Clayey Sill Sand w/ Interbedded Clay/SIH lenese EAST Corporate Remediation Group CROSS SECTION A - A SUPPLEMENTAL RF1 MAY 2004 DUPONT FAYETTEUUE PLANT CHARLOTTE, NORTH CAROLINA 6324 Falntow Road O iarfotU , NC 28210 to M M OO/Zf/lOO* GRAPHIC SYMBOLS w m Clay/Silty Clay/ \S 1 Clayey Slit Sand w/ Interbedded Clay/Sllt lenese wowBttcitniiucno A Corporate Remediation Group CROSS SECTION B - B ' SUPPLMENTAL RF1 _______ M AY 2 0 0 4 _______ DUPONT FAYETTEULLE PLANT CHARLOTTE, NORTH CAROLINA NORTH GRAPHIC SYMBOLS Cloy/SIlty Clay/ Clayey Silt Sand w/ Interbedded Clay/Sllt lenese SOUTH Corporate Remediation Group Aft J B f 0 D uP m i and CBS C ttpen CROSS SECTION C - C ' SUPPLMENTAL RF1 MAY 2 004 DUPONT FAYETTEWLLE PLANT CHARLOTTE, NORTH CAROLINA QA/M/aco* wiimm o-tf 12 G:\Fayetyle\Gis\Project_ti9ures\SupplJnvestigation\ReportYCIay_lso_map.apr (C lay/ Clayey Silt Layer Isopach Map) /V V7Z. Monitoring Well Piezometer Clay / Clayey Silt Layer Contour Line n P7P 7Rn Feet O CORPORATE REMEDIATION GROUP An Alliance between DuPont and URS Corporation - North Carolina 6324 Fairveiw Road Charlotte, NC 28210 TITLE: Clay / Clayey Silt Layer Isopach Map DuPont Fayetteville Works DRAWN: DLH CHECKED: FILE NAME: Clayjsa_m ap.apr APPROVED: DATE: 0 5 /1 4 /0 4 REVISION: 05/2 5/0 4 PROJECT NO.: FIGURE NO.: 14 _ G AFaye^G ls\Proje<J>gures\Supptinvest^Son\R eport'pal,_rnap.apr (Sile-W kte Groundwater Potentiom etrie Map) * O CORPORATE REMEDIATION GROUP D uPont an d UR S Corporation - North Carolina 6324 Fairveiw Road Charfolte, NC 28210 TITLE: Site-Wide Groundwater Potentiometrie Map DuPont Fayetteville Works DRAWN: DLH CHECKED: FILE NAME: Pot_map.apr APPROVED: DATE: 0 5 /2 5 /0 4 REVISION: 05 /2 7 /0 4 PROJECT NO.: FIGURE NO.: 15 G:\Fayatvl6\G is\ProjecLnsure3\SupplJnvesbgalion\Report\Pfop_rnwJoc_map.apr (Proposed MW/ PZ Location Map) CORPORATE REMEDIATION GROUP D u P ont a n d URS Corporation - North Carolina 6 3 24 F airve iw R oad C ha rlo tte , N C 28 21 0 TITLE: Proposed Monitoring Well / Piezometer Location Map DuPont Fayetteville Works DRAWN: DLH CHECKED: FILE NAME: Prop_mwJoc_map.apr APPROVED: DATE: 0 5 /2 5 /0 4 REVISION: PROJECT NO.: FIGURE NO.: 16 APPENDICES APPENDIX A APPENDIX B