Document 60QGZ2q8d52k1rMB7go425Od
AR226-2573
COMPILATION OF HISTORICAL C-8 DATA DUPONT WASHINGTON WORKS MAIN PLANT AND LANDFILLS
Date: January 2002
Project No: D6WW7423
h^ CORPORATE REMEDIATION GROUP An A lliance between DuPont a n d URS Diam ond
Bailey MWM eza, Building 27 Wilmington, Dataware 19805
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TABLE OF CONTENTS
1.0 Introduction......................... ................................. .
........... . 1-1
1.1 Document Organization................................
............1-1
1.2 C-8 Historical Laboratory Analysis..............
1.3 Physicochemical Data for Ammonium Perfluorooctanoate (C-8) .. ............1-2
1.4 References....................................................... .................................. ............1-2
2.0 Washington Works Main Plant......................................................
2.1 Introduction.,....... ................................................... .............. 2.2 Environmental Setting.................................. ........................
2.2.1 Geology.,............................................................... 2.2.2 Hydrology, Hydrogeology and Groundwater Flow 2.3 Water Quality........................... ............................................. 2.3.1 Surface Water Quality...................................... 2.3.2 Groundwater Quality........................................ 2.3.3 Drinlring/Tap Water Quality............................. 2.4 Site Conceptual Model................................................... 2.5 Data Gaps *****..*i>*****4r*(*>**i**********,********4*p*--. 2.6 References................................... ..................... .
..2-1 ..2-2 ......... 2-3 ..........2-3 ......... 2-3 ........ 2-6 kt*4****** ,, 2-6 ......2-6 ..... 2-7
...... 2-7 ..... 2-8 .....2-8
3.0 Local Landfill............................................................................ 3.1 Introduction.... ................................................................ 3.2 Environmental Setting.................................................... 3.2.1 Geology......................................................... 3.2.2 Hydrology, Hydrogeology and Groundwater Flow 3.3 Water Quality............................................ .................... 3.3.1 Surface Water Quality.... ................................. 3.3.2 Groundwater Quality.............................. 3.4 Site Conceptual Model..................... .............................. 3.5 Data Gaps.... ................................................................... 3.6 References............................... *.......... ............................
.3-1 .3-2 ,3-2 ,3-2 ,3-3 ,3-4 .3-4 .3-4 .3-5 .3-6 .3-6
4.0 Letart Landfill................................... 4.1 Introduction.............................. 4.2 Environmental Setting.............. 4.2.1 Geology....................... 4.2.2 Hydrology, Hydrogeology and Groundwater Flow 4.3 Water Quality............................................. 4.3.1 Surface Water Quality............. . 4.3.2 Groundwater Quality....................... 4.4 Site Conceptual Model................ ................. 4.5 Data Gaps...................................................... 4.6 References...................................... ..............
.4-1 .4-2 ,4-2 .4-2 .4-3 .4-4 .4-4 .4-5 .4-6 .4-7 ,4-8
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5.0 Dry Run Landfill.............................. ................... -........ . .................... 5.1 Introduction...., 5.2 Environmental Setting,..,.... .......................................................* 5.2.1 Geology........................................................................ 5.2.2 Hydrology, Hydrogeology and Groundwater Flow......
5.3 Water Quality................ ........................ 5.3.1 S u rface Water Quality............. 5.3.2 Groundwater Quality...............
5.4 Site Conceptual Model.......................... 5.5 Data Gaps.......................................... -- 5.6 References..............................................
TABLES
...5-1 ...5-2 ...5-2 ...5-2 ...5.3 ...5-4 ..... 5-4 ..... 5-4 ..... 5-5 .......5-6 .......5-6
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 2.1B 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 3.1B 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 4.1B Letart Landfill Analytical Data TableB - Groundwater
Table 5,0 Dry Run Landfill Monitoring Wells Construction Data
Table 5.1A Dry Run Landfill Analytical Data Tables - Surface Water
Table 5.1B p ry Run Landfill Analytical Data Tables - Groundwater
FIGURES
Figure 1.0 Solubilities o f C7F 15COOM in Water as a Function ofTemperature
Figure 2.0 Washington Works Main Plant Location and SWMU Map
Figure 2.1 Washington Works Main Plant and Local Landfill 1-mile Radius Map
Figure 2.2
Washington Works Main Plant Monitoring Well and Surface Water Sample Location Map
Figure 2.3 Washington Works Main Plant Cross Section Location Map
Figure 2.4A Washington Works Main Plant Cross Section A-A'
Figure 2.4B Washington Works Main Plant Cross Section B-B'
Figure 2.4C Washington Works Main Plant Cross Section C-C'
Figure 2.4D Washington Works Main Plant Cross Section D-D'
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Figure 2.4E Figure 2.4F Figure 2.5A
Figure 2.SB
Figure 2.5C
Figure 2.6A Figure 2.6B 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 Figure 4.0 Figure 4.1 Figure 4.2 Figure 4,3 Figure 4.4A Figure 4.4B
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 1999
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 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 Landfill 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 Letart Landfill Location Map Letart Landfill 1-mile 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'
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Figure 4.5A Letart Landfill F-Zone Groundwater Elevation Map - November 2001
Figure 4.SB 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 5.4B 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.SD 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
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Introduction
1.0 INTRODUCTION
A multi-media Consent Order was entered into between the West Virginia Department of Environmental Protection (WVDEP), the West Virginia Department o f Health and Human Resouxces-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 hmmm 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 Qroundwater 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 of C-8 in drinking water, groundwater, and surface water at and around the main plant, and the Local, Letart and Dry Run Landfills.
Pursuant to Attachment A o f 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 of C-8 in drinking water, groundwater and surface
water in and around the main plant, and tire Local, Letart and Dry Run Landfills, and to
provide a compilation of available groundwater/surface water monitoring results and
hydrogeologic characterization data for each location. This document was prepared to
meet die 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-1 of the Consent Order, hi 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 o f 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 CHaMHill Laboratory in Montgomery, Alabama. Both labs used a Gas Chromatography/Electron Capture
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Dectector (GC-ECD) based analytical method with detection limits for C-8 that ranged from 0,1 to 1.0 ug/1. CH2MHM conducted C-8 analysis for DuPont into the fall of 1998 when the laboratory ceased operation. At that time, DuPont had completed one round of 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-ECD 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.
1.3 Physicochemical Data for Ammonium Perfluorooctanoate (C-8)
C-8, also identified as PC-143, is a fluorinated surfactant used in the fluropolymer manufacturing at the main plant. Figure 1.0 shows the solubilities of C7F15COOM in water as a function o f temperature (Figure 6.9 m Kissa, 1994). The following summary lists the physicochemical data available for C-8 (Kissa, 1994):
Molecular Formula = CFj(CF2)sCOO'NEt+
Molecular weight =431.098 g/mole
LDsa acute oral rat = 680 mg/kg
B C F= 1.8
p H - 5 (0.5% aqueous)
pKa = 2.8 (-COOH)
Melting Point = 56-58eC (-COOH)
COD *700 mg/kg
O Koc " 25 Water Solubility > 1000 mg C-8/L O Vapor pressure (at 22C) = 7.1 x 10"5mm Hg
Kraft Point = 2.5 C
Q Critical Micelle Concentration = 33 mmol/L
LDm: Lethal Dose 50 - Dot* having 50% probability of causing death BOD*: Biochemical Oaygan Demand - Standard measurement is made For 5 days at 20 degrees C BCF: Bioconccntrotion Factor pKa: Negative It o f the knuauloft constant - Measure o f acidity or acid strength COD; Chemical Oxygen Demand Koc; Organic Carbon Partitioning Caeffirient
1.4 References
Kissa, E. 1994. Fluorinated Surfactants. New York: Marcel Dekker, Inc.
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Figure 1,0 Solubilities of C7F15 COOM in
water as a function of temperature (Kissa, 1994).
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2.0 WASHINGTON WORKS MAIN PLANT
Introduction..........
2-2
Environmental Setting........................ ............................................... ............- .........- ..................-- .......... ...................... -- ...... 2-3
Site Conceptual Model
............................................................... ....... ................ ....... ........... ........... -- .-- ------- 2-7
R efttenees.TM ..,...,,..,,TM ,,,,,--........--........ --................... ............ ............... ................................................ ............ -- ............. 2-8
Table 23) Table 2.1A Table 2.1B Table 2.IC
Tables Washington Works Main Plant Monitoring Wells Construction Data Washington Works Mato plant Analytical Data Table - Surface Water Washington Works Main Plant Analytical Data Table -Groundwater Washington Works Mam Plant Analytical Data Table - Drinklng/Tap Water
Figure 2.0 Figure 2.1 Figuro 2,2 Figure 2J Figuro 2.4A Figure 2.4B Figure 2.4C Figuro 2.4D Figure 2.4E Figure 2.4F Figure 2JA Figuro 2.5B Figure 2JC Figure 2.6A Figure 2.6B
Figures Washington Works Main Plant Location and SWMU Map Washington Works Mam Plant and Local Landfill 1-mile Radius Map Washington Works Mato Plant Monitoring Welt and Surface Water Sample Location Map Washington Works Main Plant Cross Sectloo Location Map Washington Works Main Plant C ra s Section A-A` Washington Works Main Plant Cross Section B-B' Washington Works Main Plant Cross Section C-C' Washington Works Mato 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 Mato Plant Groundwater Elevation Map - February 1999 Washington Works Mato Plant Groundwater Elevation Map - November 1598 Washington Works Mato Plant C-8 Concentration Map - February 1999 Washington Works Mato Plant C-8 Concentration Map - November 1998
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2.1 Introduction
The Washington Works Main Plant (main plant) is located along the Ohio River in Washington, West Virginia, approximately seven miles southwest of 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 properly 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 (RF1) conducted in the fall o f 1998 on four Solid Waste Management Unite (SWMUs) at the main plant to satisfy requirements of fire 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.
Q SWMU A-3, Riverbank Landfill: The Riverbank Landfill is about 4,500-feet long and lies along the northern edge of 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, die 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.
SW MUC-6, Polyacetal Waste Incinerators (Waste Incinerators): The former Waste Incinerators consisted of two brick-lined pits in the western portion of the manufacturing area. The Waste Incinerators operated between 1959 and 1990. The Waste Incinerators have been excavated and backfilled with clean soil.
Q SWMU H-14, Burning Ground: The Burning Ground is located in the central portion of the manufacturing area and was operated between 1948 and 1965. Since 1990, the Burning Ground la s been leveled, backfilled with clean fill aid gravel, and covered by buildings and asphalt
A previous Verification Investigation (VI) found evidence of releases of C-8 to soil and groundwater at the Riverbank Landfill, Digestion Ponds, and Burning Ground (DuPont 1992). Little evidence of releases were found in soil at the site of the former Waste Incinerators. Further investigations and evaluations were performed during the RFI to determine the extent o f releases in groundwater.
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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 T.andfill/ 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 m 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 cross sections, A-A' and F-F, are shown on Figures 2.4A and 2.4F. Four north-south cross sections, 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.
t
The average river water elevation is about 580 feet above Mean Sea Level (MSL) and die 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 mid 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 of Parkersburg,
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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 die 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, die drainage swales are dry.
Hydrogeology
Regional groundwater supplies are obtained from the Dunkard Group bedrock and Ohio River alluvial terrace deposits. The saturated portion of 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 die 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 of the Dunkard Group (Washington Formation), which consists primarily of 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: u Infiltration of precipitation falling directly on the alluvium Q 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 of water available to the alluvium depends on the degree o f hydraulic connection to the river. The degree of 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
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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) towers 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 BOOto 1,000 gpm; the seven wells in the East Well Field, which pump a combined average rate of 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 of groundwater flow is indicated by file 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 o f 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 (G l) 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 of the site production wells.
la a 1990 hydrogeotogic assessment, production well specific capacity testing of 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/fl2. 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 of 35 %, the groundwater flow velocity for several well pairs was calculated. The groundwater flow velocity was estimated at 5 feet/day (ft/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-N4W01 and K 14-MW01 in the western central portion o f the site.
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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 2.1A. 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/I 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 of installation o f 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 of C-8 in groundwater sampled at the main plant have been evaluated since 1991 (Table 2.1B), however, the wells sampled and tee 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 of 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 Ground 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 of 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 RO4-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 2rav.doc Mar. 11.02 Wilmington, DE
2-6
SO015 EID620790
Main Plan! and landfills
Washington Works Main Plant
2.3.3 Drinking/Tap Water Quality
Production Well AM07-PWQ1 (historically known as well 336) supplies potable water to the main plant. C-S 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/l, 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 toe riverbank slope either percolates into toe soil or runs off to toe 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 toe riverbank. Contact with impacted seep water is considered to be an incomplete exposure pathway due to toe 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 b p . 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 toe main plant. Other wells are AOQ8-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 of 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 toe 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-PWO1, V05-PW01, and LQ4-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 2rev.doc Mar. 11.02 Wilmington, DE
2-7
JS 0015056 EID620791
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 he minimal. Average concentrations o f C-8 in process water at the point of use (which is a mixture of 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 m ay 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 (jpeater 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 Saps
The following data gaps were identified for the main plant:
Q 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.
O Continued refinement of 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 0-8 impacted groundwater is occurring.
Surface water quality in tire 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.I. DuPont de Nemours Co. Washington Works April 1992, (Vol. 1).
______ 1999, RCRA Facility Investigation Report, DuPont Washington Works, June 30, 1999. Corporate Remediation Group.
Haskell Laboratory. 1991. Ammonium Perjluorooctanoate (PC-143).
Compilation of history data Draft 2rev.doc Mar, 11, B2 Wilmington, DE
2 -B
JS0015057 E ID 620792
Main Plant and Landfills
Washington Works Main Plant
Schultz, R.A. 1984, Groundwater Hydrology o f the M inor Tributary Basins o f the Ohio River, West Virginia
Compilation of history data Draft 2rov.doc Mar. 11,02 Wilmington, DE
2 *9
JS0015058 E D 620793
Table 2.0 Monitoring Well Construction Data DuPont Washington Works Main Plant
Washington, WV
Monitoring W ells
New ID
Old ID
Q04-MWQ2 Q05-MW01 P06-MW02 P08-MW01 N13-MW01 M16-MW01 A8-PW01 AQ09-PWI AT1O-PW01 AV11-PW01 AX13-PW0 AM07-PW01 AZ13-PW01
L04-PWOI L17-PW0! K18-PW01 K.19-PW01 K16-PW01 J17-PW01 V05-PW01
JO8-MW0J Q7-MW01 Z07-MW01 G10-MW01 T13-MW01 16-MW01 AO09-MW01 L18-MW01 V09-MW01 N04-MW01 P06-MW01 AR09-MW0I X12-MW01 AG07-MW0I AJ06-MW01
AO08-MW01
Y05-MW0I AC05-MWO1 AL10-MW0I
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 LK351) L21352) L3(353) W(354) L5(355) RANNEY TW-1 (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-61 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
Well
Slot
Diameter Size
(inches) (inches)
2
2 2
2
2
2
18 18 18 18 18 18 18
92
9S.21
201,4 16X0 108.23
98.5
105.27
18 18 8 18 NA
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
6
101.16 101.61
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
. 26
20 20
Elevation of S creen 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 -535 550-520 550 520 $50-520 550- 520
SS0-520
*
550-520
550-520 556-520
Pag 1 of 2
JSO 015059 EID62Q794
Table 2.0 Monitoring Well Construction Data DuPont Washington Works Main Plant
Washington, WV
M onitoring W ells
New ID
Old ID
I07-MWQ1 K14-MW1 D08-MWQ1 F06-MW01 U03-MW01 U05-MWQ2
U05-MW01 L04-MW01 AA04-MW01 AA05-MW01 AB07-MW02 AC7-MWQ2 AE11-MW01 AI06-MW01 E13-MW01 G17-MW01 L06-MW01
M0 M W O 2 M04-MW03 N04-MW2 N05-MW01 P04-MW02 P5-MW02 R04-MW02 S05-MW02 U04-MW01 V06-MW1 W05-MW01 Y14-MW01 Z06-MW02 Z07-MW01 Z09-MW01
'
TW-M2 TW-M3 TW-M4
TW-M5 TW-M6 TW-N2 TW-P12 TW-W1 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- 8 6 TW-87 TW-8 8 TW-89 TW-90 TW-91 TW-92 TW-93
Surface E le v atio n
(feet)
610.23 627.34 600.67 601.14 592.44 631.17 632.11
Total D epth (feet)
97.34 62.8
102.11
Well
Slot
Diameter Size
(inches) (inches)
4 4 4 4
6
6 6
Screen Length (feet)
20 20
20
597.4
43
2
10 10
630.8
70
2
10 10
630.6
72
2
10 10
633.2
74
2
io 10
629.51
72
2
io 10
634.04
72
2
10 10
623.5
74
2
10 10
630.5
80
2
10 10
629.85
77
2
10 10
593.5
25
2
10 10
593.6
26
2
10 10
593.6
26
2
10
10
633.48
82
2
10
10
590.6
28
2
10 10
631.68
80
2
10 10
593.2
28
2
10 10
631.18
78
2
10 10
593.1
27
2
10 10
629.93
77
2
10 to
630.25
76
2
10 10
629.93
90
2
10 10
640.1
72
2
10 10
629.64
74
2
10 10
630.7
70
2
10 10
Elevation of S creen 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 5603-550.5 562.85-552.85 578.5-568.5 577.6 - 567.6 577.6-567.6 561.48-551.48 572.6 - 562.6 561.68-551,68 5752-5652 563.18-553.18 576.1 -566.1 562.93 - 552.93 564.25 - 55425 549.93 - 539.93 578.1 - 568.1 565.64 - 555.64 570.7 - 560.7
M16-MW1 NI3-MW01 P8-MWQ1 004-MW02
TW-55 TW-54 TW-53 TW-50
627.14 625.87 629.29 598.76
Red and Italics - approximate - information taken off cross-section
Bold - Taken from RFI WP
Page 2 of 2
JS 0015060 EID62Q795
T able 2 *1A Summary of Analytical Results:
C-8 in Surface Water Samples DuPont Washington Works Main Plant
Washington, WV
sr . Sam ple .... OUTFALL 0D2
: ..
OUTFALL DOS
RIVER BELOW DOS RIVER BELOW PAGES RUN
'
Dale 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
; < : C -8(im /li. ; :
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 = estimated value (below laboratory quantitation limit)
TSQ015061 S ID 620796
!- & .....
Table 2.1 B Summary of Analytical Results:
C-8 in Groundwater DuPont Washington Works Main Plant
Washington, WV
SaiW f '" : : AA04-MW01 A0S-MW01 AB07-MW2 AC0-MW02 AE11-MW01 AI06-MW01 AM07-PW01
AOQS-PW01
AQ09-PW01 E13-MW01 F0&MW01 G17-MW1 K16-PW01 L04-PW1
L064V1WQ1 L.17-PW01
' : Date-
2/5/99 11/12/98 11/12/98 (dim)
2/4/99 11/11/98
2/4/99 11/18/98
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
" " 2555" ~
11/1B/9B 6/19/98 6/2/97 4/2/96
11/20/00
11/20/00 (duo) 8/15/00
5/12/99
6/19/98 6/2/97 4/2/96 10/11/01 5/12/99
5/12/99 2/2/99 11/11/98
2/2/99 11/11/98
5/12/99
mm
11/11/98
11/20/00 2/9/99 11/18/98 7/11/01 4/11/01 11/20/00
mm
11/18/98 11/18/98 (duel
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
C-Siun/D 5.43 <0.1 0.42
1.46 0.77
0.535 ^21
0.356 0.79
0.69 L 0.41
0.13 B <0.1
0,24 0.071J 0.678
osn
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 0.59 L 2 0.35 L <0.1 2.47 2.11 L 13
7.5 16.2 0.461 0.202 3.99 13.8 5.89 7.9 J 3.0 J 4.91 870
2.31 1.58
0.819 1.63
2.76 0.33 16
7.9 3.7
2
.
JSO0X5062 E ID 620797
T able 2.1 B S u m m ary o f A nalytical R e su lts (c o n 't.): . C- 8 in G roundw ater D uPont W ashington W orks Main Plant, W ashington, WV
M0444W02 MQ4-MW3 M16-MW01 N0444W02
N05-MW01 MW-AJP MW-MGM MW-TWW MWBG M13-MW01 P04-MWQ2
P05-MW02 R&MW02 P0&-MW01 Q04-MW02 Q5-MW01 R04-MW02
V05-PW01
T13-MW01
U04-MW01 U16-MW01
S05-MWQ2 V08-MW01 W0544W01 Y14-MW1 ZQ6-MW2 Z07-MW01 Z09-MW01
1 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 idUDl
2/7/99
11/12/93
2/5/99
11/13/98
4/18/96
4/18/96
4/18/96
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
TM
11/20/00
2/7/99
2/7/99 (dup)
11/18/98
2/3/99
2/3/99 (duo)
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
11/10/98 2/4/99 11/16/98 2/4/99 11/16/98 2/6/99
11/17/98
17 0.2 21.1 <0.1
3.66 U 0.86 698
696 329 380
815 13 <0.4
0.69 0.85 <0.1 29,61 <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 ' 535 0.66 L 0M L
1.30 L <0.1 R 4.2
1.6
4.7 2 11
174 690
1.91 1.7 0.729 031 4.95 L 12
0.803 4.5 2.05 3.8 2.74 <0.1 R
' .
JS0015063
EID62019
T able 2,1 B S u m m ary o f A nalytical R e su lts (c o n 't.): C- 8 in G ro u n d w a te r D uP ont W ash in g to n W orks Main P lan t, W ash in g to n , WV
RBLMW1
RBLMW2
" RBLMW3 RBLMW4 RBLMW5 RBLMW6 RBLMW7
RBLMW8 RBLMW9 RBLMW10 RBLMW11 RBIMW12 BSMW2 BGMW3
~ ~ BSMW6 ADPMW1 ADPMW2 ADPMW3
12/5/91 12/5/91 (duo)
12/11/91 12/11/91 (duo)
12/11/91 12/5/91 12/10/91
11/21/91 11/21/91 11/21/91 (duo) 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 12/5/91 12/6/91 12/8/91
R " unusable data result (relative to QA/QC) J = estimated value (below laboratory quantification fori!) L = possible low bias result (relative to QA/QC) B= compound detected in QC blank < a Non-deteci a t stated laboretory method detection limit
I 0-8(ufi/l) ' ,
140
140
65 6?
7100
550
1300
3300
40
2
2.4
3.4
14
47
4,6
2.3
4 3.6
5.6
7800
25
20000
'
CTSO015064 E ID 620799
Table 2,10 Summary of C-8 Analytical Results;
Drinking/Tap Water Samples DuPont Washington Works Main Plant
Washington, WV
BLDG 1 MAIN
BLDG 231 BLDG 293
BLDGS
" W o . . : r
10/11/01 10/11/01 (dUD)
. 8/16/00
. 10/11/01
_ 5/1Z/99
5/12/09 (dup)
10/11/01
6/12/99 6/12/99
O fffus/n
0.507 0.471 0.569
0.46 0.3D6 0.269
0.423 0.498 0.213
JSOQ1565 EID620800
Main Plant and Landfills
Local Landfill
3.0 LOCAL LANDFILL
Introduction...*....*..........
...
Environmental Setting,.*,...,..,.....
*.
Wats Qualify..........--- ----------------
Site Conceptual Model,....... .
DataGaps...-------------------
Rf^enccs..........................
Table 3.0 Table 3.A Table 3. IB
FigiseS.O Figure 3.1 Figure 3.2 Figure 33 Figure 3.4A Figure 3.4B Figure 3.5A Figure 3.5B Figure 3SC Figure 3,5D Figure 3,5E Figure 3J F Figure 3-50 Figure 3.6A Figure 3,6B Figure 3.6C Figure 3,6D
Tables Local Landfiil Monitoring Well Construction Data Local Landfiil Analytia Data Tables - Surface Watcr Local Landfiil Aaaytical Data Tables - Groundwatr
Figur
Local LndfUl Location Map
Local Landfiil and Washingron Works Main Plant -mile Radius Map
Local Landfiil Monitoring We and Surface Water Sarnple Location Map
Local Landfiil Cross Section Location Map
Local Landfiil Cross Section A-A*
'
Local Ladfill Cross Section EFB'
tnra) Landfiil Gfcmndwacr Elvation Msp - November 2001
Local Landfiil Grqundwatf Elvation Map - Deceffiber 2000
Local Landfiil Grouadwater Elvation Map - November 1990
Local Landfiil Gfoundwatcr Elvation Map - Novcmber 199$
Local Landfiil GfOiindwater Elvation Map - Novcmber 1997
Local Landfiil Oroundwater ElvationMap - Becftaber 996
Local LrtdfiD Gfouftdwaer Elvation Map - Decerober 1994
Local Landfiil 0 8 Cnctinmion - May 2001
Local Landfiil C-8 Concentratim - May 2000
Local Landfiil 0 8 Concentration - May 1999
Local Laadfll C-8 Concentration May 1998
Completion of history data Draft 2rev.doc Mar. 1 1,02 Wilmington, DE
JS0015066 E ID 620801
Main Plant anti 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 of 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 of 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/Nadonal 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 of 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 of about 5 X IQ"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 of massive sandstone and siltstone underlying varying amounts of soil cover and man-made landfill plateaus. The locations of 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 of 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 2rev.doc Mar. 11.02 Wilmington, DE
JSO O li E ID 620802
Main Plant and Landfills
Local Landfill
The bedrock at the Local Landfill consists o f mter-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 die sandstone layers dip gently towards the north. Most of the sandstone layers located in the upper portion o f die 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 days (where these clays exist) and the weathered bedrock (DuPont, 1992). In addition, infiltration of precipitation into the cells is limited by approximately 2-feet of 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 of the continuous and discontinuous sandstone layers having low permeability o f 1 x 10'5cm/sec. The sandstone layers are separated by laterally continuous shale layers. Well yields from the sandstone layers are very low, ranging from <0.5 gpra 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 withto 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 date as required by the WVNPDES Permit No. 0076538. Figures 3.5A through 3.5G present maps for 2001 through 1996and 1994, The groundwater contours were
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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 downsbpe 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 unconflned 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 3.1 A 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 outfhlls, 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 die leachate ponds, . had a concentration o f 3 1 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 of the side, have decreased from 54 ug/1 to 12 ug/1 over the course o f 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-1Q was sampled twice in 1998 and 1999. The limited
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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 them 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 die landfill starting and ending near the landfill's electrically operated gate. Hie 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, ihese 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 of cracking or erosion (which could allow surface water to enter the solid waste deposit) and evidence of settling of solid waste (causing ponding o f surface water). Per Condition G-l 6 of toe 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 of the soil cover reduces the amount of 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 further 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,
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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 rase 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 mid 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 die 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 of 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.
. O Gather additional C-8 concentration data from monitoring wells for plume delineation.
Activities to fill the date 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).
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Table 3.0 Monitoring Well Construction Data
Local Landfill Washington, WV
M onitoring W ells LLMW-14 LLMW-16 LLMW-i9 ULMW-I1Q
III
Surface
W ell
Slot Screen Elevation of
E le v atio n
D iam eter Size
Length S creen Interval
(feet)
(inches) (inches) (feet)
(feet)
844.7
155
4 0.020 20 717.2-697.2
793.2
90
4 0.020 20 723.2-703.2
788.54
80
4
0.020
20 728.54-708.54
805.94
87
4
0.020
20 738.94-718.94
i
EID620807
u
to
oO' u
o
M
Table 3.1A Summary of Analytical Results: C-8 In Surface Water Samples
Local Landfill Washington, WV
Sun pic LEACHATE OUTFALL 004
OUTFALL 005
" OUTLET 001 " OUTLET 002
OUTLET 003 OUTLET 101 STREAM 1 STREAM 2
y-i: . CfS/uE/O
2/16/1904
31
9/27/2000
4.73
12/10/1999 _ 6/3/19B9
7.1 3.06
6/2/1898 5/29/1997
12 13
4/2/1998 2/16/1994
13 11
9/27/2000 12/10/1999
6/3/1SB9 _ 6/2/1998
13.3 34
6.8 39
5/29/1997
..........
41
4/2/1996 2/18/1994
39 35
6/29/1997 4/2/1996
..
80 61
5/29/1997 4/2/1996
<02 72
5/29/1997 4/2/1990
23 20
9/14/2000 6/3/1999 6/2/1998
5/29/1997 4/2/1996
9/14/2000
12 15 54
11 72 4.12
12/29/1999
10.7
6/2/199B 4/2/1996
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Table 3,1 B Summary o f Analytical Results:
C-8 In Groundwater Local Landfill
W ashington, WV
LLMW -4 LLM W -6 LLM W -9 LLM W -10
' " B ite . .-V : 5 /1 0 20 0 1 5 /1 1 /2 00 0 5 /19/1999 5 /2 7 /1 9 9 0
4/1 1 /1 99 6 5 /1 6 /2 0 0 1 5 /4 0 /2 0 0 0 5 /1 9 /1 9 9 9
'"
5 /2 7 /1 9 9 8 4 /11/1996
5 /1 6 /2 0 0 1 710/2000 5 /20/1999 5 /27/1998 4 /1 1 /1 9 9 6
5 /2 0 /1 9 9 9 5 /2 8 /1 9 9 8
1.4 10 1 6 .2 26 39
3 1.42 1,32 9 15 0 .0 3 9 4 0.029 0.046 J < 0 .1 0 .1 4
0 .1 5 0 .2 2
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4.0 LETART LANDFILL
Introduction-- Environmental Setting.----Water Quality.. Site Conceptual Model.,
D&taGaps.......,,
References...
Table 4.0 Table 4.1A Table 4.1B
Figure 4.0 Figure 4.1 Figure 4 2 Flguie 43 Figure 4.4A Figure 4,4B Figure 43A Figure 4.5B Figure 4.5C Figure 43D Figure 43E Figure 4,5F Figure 4.6A Figure 4.6B
Figure 4.6C Figure 4.6D
Tables Letart Landfill Monitoring Welle Construction Deta Letan Landfill Analytical Data,Tables - Surface Water Letart Landfill Analytical Data Tables - Groundwater
Figures Letart Landfill Location Map Letart Landfill 1file 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 LetUt Landfill F-Zone Groundwater Elevation Map - January 2001 Letart Landfill F-Zone Groundwater Elevation Maf) - October 1999 Letait 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 Letart C-8 Concentration Map - July 2001 Letart C-8 Concentration Map - January 2000 Letart C-8 Concentration Map - July 1999
LetartC-8 Concentration Map November 1991
,.4-2 ,,4-2
..4-6 ..4-7 ,,4.8
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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 of 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 of highly plastic clay and silt having a permeability o f about ID'7cm/sec (DuPont, 1993). The soil thickness ranges from 4 to 14 feet, averaging about 8 feet in thickness.
Letart Tfu lfill 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 of C-8 in fee 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 were 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 of 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 of 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 of die Permian age Dunkard Group. The maximum thickness o f the Dunkard Group in this region is 570 feet. The location of 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.
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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 of 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 of the geomembrane. Alternatively, precipitation may flow via overland flow on top o f the vegetative layer downslope. In either situation, tins 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 teat these zones display low hydraulic conductivity (Tetra Tech Richardson, 1990). Zone A hydraulic conductivity is low, ranging from 10-4cm/sec to less than 1Q'Scm/sec. (There are no wells monitoring Zone B, therefore, it was not tested.) Zones C and F have very low hydraulic conductivities ranging from 10'6cm/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 of the > landfill. Most current groundwater monitoring is conducted in Zone F;
The low hydraulic conductivity can be attributed to the very fine-pained nature o f the
water-bearing units. In addition, many sandstoneunits in the region typically display
effective porosity as low as 1 percent This low porosity results from pore space being filled in by authigenlc 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 tee F zone indicate that groundwater flow beneath the landfill is very slow, attributable to the
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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 of 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, IM W -10 and LMW-11, were installed in October 2001 to provide additional data from Zone F to the north and south of 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 of monitoring wells within Zones A, C and D/E prevents determination of 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 east of 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 tire 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 of groundwater elevations of 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 0 8 has been performed periodically since 1991. This data is presented in Table 4.1A. The two locations sampled most frequently, the Upper and Lower ponds, no longer exist. During construction of 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)
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and ate being sampled. These locations include the leachate from die landfill [location OO20eachate basin)] and the stream located slightly east of the property line along Rt. 33. The locations of 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 4.1B 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, die 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 of the groundwater data does not show any obvious overall concentration trends (Table 4.1B). 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 tile installation of 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 ft at LMW-5B. This is higher than the most recent groundwater elevation measurement and therefore, is a conservative value.
O H ie length o f the aquifer discharging to the Ohio River is 1000 ft based on the geologic cross-sections.
O The historical mean value of 855 ug/J for LMW-5B, a downgradient well, represents the concentration o f C-8 in tile aquifer.
O The velocity o f groundwater in the aquifer is 0.01 ft/day. Groundwater average linear velocities for the F zone are calculated to be 0,01 ft/day from the north to the southwest and 0.003 ft/day from the north to the southeast (DuPont, 2000).
Using these assumptions, the calculation for loading to the Ohio River is shown below:
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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/l09ug)x(lkg/lOOOg) x (1 lb/2.205kg) x (4.785 1/gal)
- 1,47x1O'9 lb/gal x 682,550 gal/yr
= 1x 1Q'JIb/yr
Fetimated 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 he 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 of 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 of 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
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migrated downward through the landfill material. These waters continued to flow as groundwater downward towards Zone F where it then flowed laterally to die west and south. Currently, the engineered cap prevents surface water from contacting die landfilled materials allhough 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 [QQ2(Ieachate 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, diis 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 of 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 Date 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.
Q Determine the C-8 concentration in the Ohio River.
Determine the C-8 concentration in streams and other surface water bodies.
Acquire additional geological data to refine 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.
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4.6 References
DuPont 1993. Letart Landfill Hydrogeologlc 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.
Completion of history data Draft ?rsv.doc Mar. 11,02
Wilmington, DE
4 *6
JSO15082 EID62Q817
Table 4.0 Monitoring W eil Construction Data
Lstart Landfill Letart, W V
Zone A
c D
F
;i
M onitorina W ells
LMW- 1
LMW-: 7
LMW- 8
LMW- !3 LMW- ;3A
LMW- 4
LMW- 6A
LMW- 2A
LMW- 5B
LMW- 6
LMW- 9
LMW- 10 LMW- 11
Surface E le v atio n
(feet) 768.53 770.24 777.06 673.1 i 672.61 649.17 645.23 778,53 644.39 754.22 774,85 732.37 774.34
T o ta l
D epth (feet)
33 35 38.5 30 60.1 28 28 180.8 72 183 225 189.85 161.5
W ell Diam eter
(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
L en g th
(feet)
5
10
9
5 5
5
10
30
20
30
20 20
25
Elevation of S creen Interval
(feet)
740.24-/00.2* 748.08-739.06
650.1-645.1 619.61-814.61 626.17-621.17 627.23-621.23 628.53-598.53 594.39-574.39 606.22-576.22 572.85-S52.B5 562.52-542.52 637.84-612.84
Table 4.1A Summary o f Analytical Results; C8 in Surface Water Samples
Letart Landfill Letart, WV
*
W hdKt
" : : - . Date
.
002(LEACHATE BASIN)
7/25/2000
4/3/2000
1/14/2000 10/21/1999
LEACHATE
11/27/2001 7/20/01
7/25/2000 7/20/1999
LOWER POND
1/14/2000 4/3/2000 10/21/1986 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 2/6/1031.... 1/18/1991
~
N SPRING FLOW RT 33 STREAM
3/12/1992 3/12/1992 7/20/2001 7/31/2000"...... 7/20/1999 7/23/1997 4/17/1998 "
STREAM MN RD
3/15/1994 9/20/1994
SW SPRING FLOW UPPER POND
3/12/1992 7/19/1999
5/26/1998
7/23/1997
4/17/1998 3/15/1994
12/27/1991
11/22/1991
4/26/1991
3/22/1991
2/8/1991
1/18/1991
O-Sfogm
1350
1900
920
3240
53.2
159
2250
1030
1410
1260
2530
1190 1100 1600
lS86 2200
730 1300
1000 670 TCJ5
~
400 '
1200
0.3
0.3
2.01
0.573
23
2 1.8
0.5 0.9
1
517
480
<200
2100
4400
4100 ,
790
930
500
2300
2900
1:
" TM
JS 00150B 4
E ID 620819
Table 4,1 B Summary of Analytical Results;
C-8 in groundwater Letart Landfill Letart, W V
, r a
. SfiMDli LMW-3A
LMW-4
LMW-5A
'
M fe. 7/1911999 11/22/1991 3/22/1991
4/3/2000 1/14/2000 11/&/1991 3/28/1991 11/22/1991
3/22/1991
......... j C - 8 ( e / Q ___
60.3 350 380
272 172 830 690
0.8
1.6
JSO015085 E ID 620820
Table 4.1B Summary o f Analytical Results (Con't):
C-8 in Groundwater Letart Landfill Letart, WV
\'
:' Ssmole LMW-3
C -Zuoe W ells
v i : Date" ' ' 11/22/1991 3/22/1991
P~8 (ug/I) 1000
390
,
JSO 0X 5086 EID620821
Main Plant and Landfills
Dry Run Landfill
5,0 DRY RUN LANDFILL
Environmental Setting,TMTM....... ................................... ........................................................................ .......................................... 5-2 Wat Quality..................... ................ ......... .................................. ....... ..................... .......................................... ....................... 5-4 Site Conceptual ModelTM---------------- ---------------------------- ----- ------------------------- --- ------------ ------------- -------------5-5 Data Gaps...... .......... ................... ................ ..................... ......... ..................................................-- ---------- ------------------- 5-6 References............. ................ ...........-- - ............ .........-....................... ...................................................................... .-- ..5-6
Table 5.0 Table 5.1A Table 5.1B
Table* Dry Run Landfill Monitoring Wells Construction Data Dry Run Landfill Analytical Data Tables - Surface WaterDry Run Landfill Analytical Data Tables - Groundwater
Figure 5.0 Figure 5.1 Figure 5,2 Figure 5,3 Figure 54A Figure 5.4B Figure 5.5A Figure 5.58 Figure 5.5C Figure 5,5I> Figure 5.5E Figure 5.6A Figure 5-6B Figure 5.6C Figure 5.6D Figure 5.6E Figure 5.6F
Figures Dry Run landfill Location Map Diy Run Landfill 1-mile Radius Map Dry Run Landfill Monitoring Well and Surface Water Sample Location Map Dty Run Landfill Cross Section Location Map Dry Run Landfill Cross Section A-A` DryRun 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 ]993 Dry Run Landfill Groundwater Elevation Map - April 1992 Dry Run C-S Concentration Map Bedrock Wells - July 2000 Dry Run C-S Concentration Map Bedrock Wells - M y 1999 Dty Run C-8 Concentration Map Bedrock Wells - July 1997 Dty Run C-8 Concentration Map Overburden Wells - July 2000 Dry Run C-S Concentration Map Overburden Wells - Jiily 1999 Dry Run C-8 Concentration Map Overburden Wells - May 199B
Compilation of history data Draft 2rev.doc Mar. 11, 02 Wilmington, DE
5-1
JSO015087 EID620822
Main Plant and Landfills
Pry Run Landfill
5.1 Introduction
The Dry Run Landfill is located west o f the town o f Lubeck, in Wood County, West V irginia (Figure 5,0) and is about eight miles southwest of the Washington Works main plant m d the Local Landfill. A water use and well survey search is being completed for die 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 of 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'ffiOBthly outfall surface' water 'monitoring. ............ ........... ......
Figure 5.2 shows the location of the landfill, monitoring wells and surface water campling points. The landfill was constructed within the drainage basin of Dry Run, a tributary o f the North Fork o f Lee Creek, which is a tributary of the Ohio River. The Dry Run l andfill has no compacted or synthetic bottom liners. However, natural soil present in rW the landfill material is composed of clay and weathered shale.
The Dry Run Landfill receives waste from the main plant consisting of non-hazardous waste inr.lnding 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 of 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 of 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 of heavy clays derived from the weathering o f shale. A yfttiwlmmnl investigation for the Dry Run Landfill was completed by DuPont (1996). The investigation consisted o f advancing soil test borings, test pits, laboratory testing of soil physical properties, stability analyses, and settlement analyses. DuPont (1996) determined that the natural residual soil underlying toe landfilled materials consisted of 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 2rev.doc Mar. 11.02 Wilmington. D
JSO015088 E ID 620823
Main Plant and Landfills
Dry Run Landfill
overburden wells (DBMW 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 of two cross-sections, A-A* and B -B \ crossing the landfill and downgradient of 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 A A ' (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 -13) 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 of 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-shaped 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 ie North Fork o f Lee Creek.
Poteste Sc 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). Potest (1989) also evaluated the 24-hour precipitation amount that would result in full flow conditions at the location where the capacity was estimated. Poteste determined that precipitation values between 5.25-5.99 inches in 24 hours would result in full flow.
The installation of a leachate collection system at tire Dry Run Landfill encompassing the inactive lower half of the landfill was completed by Potest & Associates Inc, in 1999. . Leachate from the landfill discharges into a leachate collection sump located northwest of 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 of 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 2rev.doc Mar. 11,02 Wilmington, 0E
5-3
JS001S069 EID620824
Main Plant and Landfills
Dry Run Landfill
wells (DRMW-6A, -12A,-12B, and 13A), and four bedrock wells (DRMW-12,-13, -14, and -15) still exist. The other seven wells were abandoned in 1999 by Potesta & Associates, Me. 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 foe 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 foe shallow water encountered in the overburden section.
Annual groundwater elevation maps for foe 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 foe original maps submitted for the permit to foe updated Dry Run Landfill base map. These maps show that groundwater in foe bedrock aquifer flows from foe southeast towards foe northwest. The groundwater elevations measured for nested wells (DRMW-12, -12A, and 12B, and DRJVfW-13 and -13A) are similar and foe 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 W ater Quality
Historical surface water C-8 concentrations are presented in Table 5.1A 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 of C-8 in foe 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 5.1A).
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 foe sampling events for foe 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 foe highest concentration of C-8 exists in monitoring wells 13 and 13A, bedrock and overburden wells, respectively.
Compilation o! history data Draft 2rev.doE Mar. 11, 02 Wilmington, DE
5-4
JSO015090 EID620825
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 tiie 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 Sit 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 mam plant where the leachate is treated) is considered a potentially complete but limited exposure route for the landfill and plant workers and samplers.
Currently, tiie inactive lower half of the landfill is covered by geotextiles mid geomembranes o f tiie 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 felling in the upper halfo 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 (towngradient. 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 of 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.
CompBation of history data Draft 2rav.doc Mar, 11,02 Wilmington, DE
. 5-5
JSO015091 E ID 620826
Main Plant ant) Landfills
Dry Run Landfill
5.5 Data Gaps
The following data gaps were identified for the Dry Run Landfill: Identify the locations of seeps in the 01167 walls and determine water quality with respect to C-8 concentration. Determine the C-8 concentration in streams aid 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.
Potest & Associates, Inc. 1989. Hydrologic and Hydraulic Analysis o f Dry Run, Area N o .l. October 9,1989. Letter from D. Mark Kiser to Dan Weber.
1999. Monitoring Welk MW-I, MW-1A, MW-4, MW-4A, MW-6, MW-10, MW10 Abandonment Report, Dry Rim Landfill, DuPont Washington Works, March 1999,
T esa Tech Richardson. 1989. Monitoring Well Installation Program, October 1989.
Compilation of history data Draft 2rev.doc Mar. 11,02 Wilmington, D i
5-6
EID620827
Table 5.0 Monitoring W ell Construction Data
Dry Run Landfill Lubeck, WV
M onitorina W ells DRMW- 14
DRMW- 13
DRMW- 13A
DRMW- 12 DRMW- 12ft DRMW- 12B DRMW- 6A
DRMW1- 15
Surface
E le v atio n (feet} 936.14 720.6
720,3 730.5 730.3 730.5 744.93 730.87
T o ta l
D epth (feet) 260
35
11
35 17 15
12.2
45
W ell
Diam eter (inches)
10
4
4 4 4 4
2 2
Slot Size finches) NA
0.010 0.010 0.010 0.010 0.010
0.010
Screen L en g th (feet)
NA 15
5 15 5
10
20
Elevation of S creen Interval
(feet) NA
700.6-685.6
714.3-709.3 710.5-695.5 718.3-713.3 725.5-715.5
705.87-685.87
m s
JSO01593
Table 5.1A Summary o f Analytical Results: C-8 In Surface W ater Samples
Dry Run Landfill Lubeck, WV
----- -
DOWN STREAM DRLEACHATE
OUTLET 0Q1
PROPERTY BOUNDARY
STREAM SAMPLING PO!NT#1 | STREAM SAMPLING POINT#2
'
Djrtis.-rYf*?! 4/9/1996
7, , ^--
; ......... 25
10/3/2000
27.4
" 12/29/1999
34
5/19/1998
56
7/22/1997
62
10/3/2000
31.5
12/29/1999 " 5/19/1998
`
66 17
4/9/1996
86
10/3/2000
10.3
4/9/1996
9.9
7/14/1998
0.88
12/29/1999
39
10/3/2000
0.753
12/29/1999
0.54
5/19/1 56
1
10/3/2000
27.6
12/29/1999
87
5/19/1998
4.6
.. .
JS0015094 E ID 620829
Table 5.1 B Summary o f Analytical Results:
C-8 in Groundwater Dry Run Landfill Lubeck, WV
. i- : DRMW-12
DRMW-12A
DRMW-12B DRMW-13 DRMW-13A
DRMW-14
DRMW-15 .... " ORMW-6
DRMW-6A
21 M ttf tc 'i. si/
7/19/2000 7/21/1999 5/26/1B98 7/22/1997 4/10/1996
7/19/2000 7/21/1999 5/26/1996 7/22/1997 4/10/1996 7/20/2000 7/21/1998 6/16/1996
7/20/2000 7/21/1999 5/26/1998 7/22/1997 7/20/2000 7/21/1999 S/26/1998 7/22/1997 4/10/1986 4/10/1996 (duo)
7/20/2000 7/21/1999 -------- 6/16/1998 7/21/1997 4/10/1996
7/20/2000 " 7/21/1899
7/22/1897 4/10/1996
7/20/2000 7/21/1999 5/26/1998 7/22/1087 4/10/1998
0.16 0.134
<0.10
<0.1 <0.1
0.128 -- 0.081 J
<0.10 <0.1 <0.1
ND 6.0291 5.4
<0.1
9.6 3.6 9.2 7
9.9
0.070 J 8.7
18 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
J= estimatedvalue (belowlaboratory quantitationlimit).
JSQ015095 EID620830
II
J
FIGURES
j JSO 015096
E ID 620831
Figures can be found on hard copy in central files.
i
i JSO015097
E ID SZ O S^
il
i#'
''
h
APPENDIX 1 CONSENT ORDER (ORDER NO. GWR-2001-019)
y
nr
..
JSO015098 EID62Q833
