DEPARTMENT OF THE ARMY INSTALLATION MANAGEMENT COMMAND HEADQUARTERS, UNITED STATES ARMY GARRISON, PICATINNY

Transcription

1 t REPLY TO ATTENTION OF Environmental Affairs Division DEPARTMENT OF THE ARMY INSTALLATION MANAGEMENT COMMAND HEADQUARTERS, UNITED STATES ARMY GARRISON, PICATINNY PICATINNY ARSENAL, NEW JERSEY October 21, 2010 SUBJECT: Comprehensive Environmental Response, Compensation and Liability Act (CERCLA)/Interagency Agreement (IAG) Administrative Docket No. II-CERCLA- FFA : Submittal of draft Picatinny Area C Groundwater Long Term Monitoring Draft Report, Round B, ; ; Review is ER,A-eligible Mr. William Roach U.S. Environmental Protection Agency Region Broadway, 18 th Floor New York, NY Mr. Gregory Zalaskus New Jersey Department of Environmental Protection Emergency Management Program East State Street, Floor 5, P.O. Box 028 Trenton, New Jersey Dear Sirs: Enclosed for your review is the Picatinny Area C Groundwater Long Term Monitoring Draft Report, Round B developed by Shaw for and approved by Picatinny and the Army. The results of this latest round of semi-annual sampling that were briefly discussed at 7 October Restoration Advisory Board meeting and are consistent with the historical groundwater data from these wells. Sincerely, Project Manager for Environmental Restoration Enclosure Copies Furnished: NJDEP, Mr. Marchesani RAB Co-chair: PDF of Report only TAPP contractor, Barbara Dolce PDF of Report only 1

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3 Section TABLE OF CONTENTS Page 1.0 INTRODUCTION SITE SETTING AND HISTORY AREA C SETTING AND HISTORY TOPOGRAPHY AND SURFACE WATER HYDROLOGY GEOLOGY AND SOILS HYDROGEOLOGY SUMMARY AND FINDINGS OF PREVIOUS SITE INVESTIGATIONS Groundwater ANALYTICAL AND FIELD SAMPLING PROGRAMS SUMMARY OF ANALYTICAL RESULTS VOLATILE ORGANIC COMPOUNDS EXPLOSIVES METALS DIOXINS AND FURANS ANIONS REFERENCES... 8 W912DR-05-D-0026 i Area C Semiannual Groundwater Data Report, Round B

4 LIST OF TABLES Table 1 Sampling Location and Analysis Summary 2 Analytes Detected in Groundwater Area C 3 Analytes Detected in Groundwater Southern Boundary W912DR-05-D-0026 ii Area C Semiannual Groundwater Data Report, Round B

5 LIST OF FIGURES Figure 1 Location of Area C and Picatinny Arsenal 2 Area C Site Map 3 Area C/Southern Boundary Monitoring Well Map 4 Long-Term Groundwater Monitoring Well Locations W912DR-05-D-0026 iii Area C Semiannual Groundwater Data Report, Round B

6 LIST OF APPENDICES Appendix A B C Chain of Custodies and Analytical Results Sampling Data Sheets Well Assessment Checklists W912DR-05-D-0026 iv Area C Semiannual Groundwater Data Report, Round B

7 LIST OF ACRONYMS AND ABBREVIATIONS µg/l... micrograms per liter AEDBR... Army Environmental Database Restoration bgs... below ground surface COC... Chemical of Concern DCE... Dichloroethene Empirical... Empirical Laboratories, LLC FS... Feasibility Study FSP... Field Sampling Plan ft/day... feet per day ft/ft... feet per foot HASP... Health and Safety Plan ICFKE... ICF Kaiser Engineers LOC... Level of Concern LTGM... Long-Term Groundwater Monitoring mg/l... milligrams per liter NJDEP... New Jersey Department of Environmental Protection ORP... Oxidation-Reduction Potential QAPP... Quality Assurance Project Plan ROD... Record of Decision RI... Remedial Investigation Shaw... Shaw Environmental, Inc. SB... Southern Boundary PCE... Tetrachloroethene TCE... Trichloroethene USACE... United States Army Corps of Engineers USEPA... United States Environmental Protection Agency USGS... United States Geological Survey VOC... Volatile Organic Compound W912DR-05-D-0026 v Area C Semiannual Groundwater Data Report, Round B

8 Section 1.0 Introduction 1.0 INTRODUCTION The United States Army Corps of Engineers (USACE) tasked Shaw Environmental, Inc. (Shaw) to perform semiannual groundwater sampling as part of the Long-Term Groundwater Monitoring (LTGM) Plan for Area C. Area C Groundwater is designated Army Environmental Database Restoration (AEDBR) Site PICA-206. The objective of the groundwater monitoring program is to ensure that site conditions remain protective of human health and the environment and that chemicals of concern (COCs) in Area C groundwater do not migrate off post in concentrations above levels of concern (LOCs). The semiannual sampling consists of groundwater sampling of 32 monitoring wells within both Area C and the southern boundary. The southern boundary is the point where some Picatinny Arsenal groundwater flows off post. The second round of semiannual groundwater sampling was conducted from June to August 2010 and the analytical results are summarized in this report. This report presents a summary of the analytical results from sampling which occurred from June to August Section 2.0 includes a brief physical setting and site history summary. Section 3.0 includes a brief discussion on the analytical and field sampling program. Section 4.0 includes a summary of analytical results from the second semiannual groundwater sampling event for Area C. W912DR-05-D Area C Semiannual Groundwater Data Report, Round B

9 Section 2.0 Site Setting and History 2.0 SITE SETTING AND HISTORY A complete description of the Picatinny Arsenal regional setting and history is provided in numerous other reports, including the Phase I Remedial Investigation (RI) Draft Final Report (Dames and Moore, 1998), and therefore will not be reiterated in this document. 2.1 AREA C SETTING AND HISTORY Area C is approximately 126 acres in size, and is located in the southern portion of Picatinny Arsenal, near the southern boundary of the Arsenal. The area is bounded by Green Pond Brook to the northwest, Route 15 to the southwest, and the Picatinny Arsenal boundary to the east. Figure 1 illustrates the location of Picatinny Arsenal as well as Area C and the southern boundary within Picatinny Arsenal. Figure 2 illustrates the location of the five sites within Area C. The five sites in Area C include Site 19 (Pyrotechnic Demonstration Area), AEDBR site PICA-020; Site 25 (Sanitary Landfill), AEDBR site PICA-067; Site 26 (Dredge Pile), AEDBR site PICA-068; Site 163 (Baseball Fields), AEDBR site PICA- 092; and Site 180 (Waste Burial Area), AEDBR site PICA-093. Groundwater at these sites is considered part of the Area C operable unit. Site 34 (Burning Ground) AEDBR site PICA-002 is geographically located in Area C. However, Site 34 is not part of the Area C Groundwater operable unit. The Burning Ground has its own groundwater monitoring plan. The Record of Decision (ROD) for the Burning Ground was signed by Picatinny Arsenal and the United States Environmental Protection Agency (USEPA) in The decision to group groundwater from all Area C sites with the exception of the Burning Ground was made with the agreement of the regulatory community. Area C groundwater once included Site 23, the Post Farm Landfill, which is located on the southeast ridge of Picatinny Arsenal. Site 23 was removed from the Area C designation, and groundwater at Site 23 was addressed as part of the Feasibility Study (FS) for site 23 (IT, 2001); a final ROD for Site 23 was signed by the Army and USEPA in December 2004 (Shaw, 2004a). It should also be noted that the Former Skeet Range is located within the boundaries of Area C. However, the Former Skeet Range is not a CERCLA RI site, because it was still being used as a skeet range into the 1990s; it is currently being investigated as a compliance site. The identification of the Former Skeet Range as a contaminated area came after the other sites mentioned above had completed the RI phase of the CERCLA process and operations at the range were discontinued. A Remedial Investigation for the Former Skeet Range should be completed within the next few years. There was concern about groundwater contamination in Area C due to historic activities that have been conducted within the area, such as land filling (Site 25), dumping (Site 180), and testing (Site 19). Further, because the southern boundary is the point where some Picatinny Arsenal groundwater flows off post, the Army wanted to ensure that human health and the environment would be protected from unacceptable risk. The Army has investigated these concerns and worked with the USEPA and New Jersey Department of Environmental Protection (NJDEP) to ensure the investigation was complete. 2.2 TOPOGRAPHY AND SURFACE WATER HYDROLOGY The western half of Area C is flat and is in the floodplain of Green Pond Brook. The eastern half of Area C runs from the floodplains up in elevation to the unnamed southeastern ridge. The topography in Area C does not vary considerably. All of Area C is an essentially flat floodplain, approximately 685 to 695 feet above mean sea level (amsl). Topography, roads, and physical features of Area C are displayed on Figure 2. Surface water runoff in the floodplain is controlled by a system of engineered drainage ditches. The drainage ditches carry water into Green Pond Brook. Surface water runoff from the eastern half of Area C flows rapidly down elevation into the western floodplain of Green Pond Brook. No recreational activities are associated with Green Pond Brook or the contributing drainage ditches in this area of the facility. 2.3 GEOLOGY AND SOILS Precambrian Gneiss bedrock comprises the southeastern ridge and slope of Area C where it is overlain by approximately five to 130 feet of glacial deposits. The Leithsville Dolomite occurs in the valley region of Area C, where it is overlain by up to 210 feet of glacial deposits near the center of the valley. W912DR-05-D Area C Semiannual Groundwater Data Report, Round B

10 Section 2.0 Site Setting and History The glacial deposits thicken toward the center of the valley and dip along the southwest strike of the valley. Hardyston Quartzite occurs between the Precambrian Gneiss and the Leithsville Dolomite and is estimated to be overlain by approximately 210 feet of glacial deposits. Both the Leithsville Dolomite and Hardyston Quartzite are Cambrian in age and do not crop out in Area C. Three major faults that strike along the valley cut these and other bedrock units at Picatinny Arsenal. A number of smaller cross faults that cut only the Proterozoic gneiss units in the western part of the valley have also been identified. Bedrock formations dip steeply to the northwest and are overlain by undeformed glacial sediments. 2.4 HYDROGEOLOGY Groundwater at Area C has been defined and monitored with a network of 42 monitoring wells which are considered to be part of the Area C operable unit, including the 16 wells located along the southern boundary of the facility and Area C, designated as the southern boundary wells. All southern boundary wells begin with an SB designation. Figure 3 shows the approximate location of the monitoring wells in Area C. Four separate aquifers have been identified in Area C. The aquifers consist of an unconfined glacial aquifer, an upper semi-confined glacial aquifer, a lower semi-confined glacial aquifer, and a bedrock aquifer. The unconfined aquifer corresponds to the upper unit of sediments. The unconfined aquifer occurs closest to the surface, has a thickness ranging from three to 35 feet, has an average horizontal gradient of 0.007, and has an average hydraulic conductivity of 23 feet per day (ft/day) (Dames and Moore, 1998). The upper semi-confined aquifer corresponds to the intermediate fine-grained unit of sediments and is encountered at depths ranging from 20 to 50 feet below ground surface (bgs). This aquifer is made up predominantly of silt and clay and is a low permeability unit. Since the upper semi-confined glacial aquifer is finer-grained than the overlying and underlying aquifers, it retards downward groundwater flow to the lower semi-confined and bedrock aquifers. Two wells within Area C, LF-2 and SB1-3, are screened within the upper semi-confined aquifer. No hydrogeologic characterization data is available for this aquifer within Area C. However, slug tests were conducted within the upper semiconfined aquifer up valley of Area C at Site 78 (78MW-2). Results of these slug tests indicate a hydraulic conductivity of 4.6 ft/day. The hydraulic gradient was calculated to be feet per foot (ft/ft) based upon synoptic water level measurements collected in July 2003 at monitoring wells MW24-4B and LF-2. The top of the lower semi-confined aquifer is encountered at depths ranging from 35 feet bgs in the northern portion of Area C to 150 feet bgs near the southern portion. The thickness of this aquifer ranges from 0 feet on the southeastern ridge to 163 feet in the center of the valley. As reported in the Phase I Remedial Investigation (RI) report (Dames and Moore, 1998), the average hydraulic gradient in the lower semi-confined aquifer is ft/ft and the average hydraulic conductivity is 34 ft/day. 2.5 SUMMARY AND FINDINGS OF PREVIOUS SITE INVESTIGATIONS Numerous groundwater investigations have been performed within Area C. The following sections present an overview of the findings of these investigations. For more detail regarding these results please refer to the final FS (Shaw, 2005) and the Area C Groundwater Long-Term Monitoring Report, Round A (Shaw, 2010) Groundwater The most comprehensive and recent data sets (1998 Phase I RI and Area C/Southern Boundary groundwater monitoring) were used to evaluate the groundwater quality. Data sets and additional detail about the previous investigations are available in the administrative record. The Phase I RI Report concluded that there were only limited exceedances of volatile organic compounds (VOCs) and dioxins/furans in groundwater in Area C. Detections of explosive compounds appeared to be related to activities at the Burning Ground (Site 34) and the pyrotechnic area (Site 19). Exceedances of lead and arsenic were widespread throughout the area with no specific identifiable source (Dames and Moore, 1998). In February 2000, the Army, NJDEP, and USEPA agreed that additional sampling would be conducted to confirm that the extent of detections in Area C groundwater was still consistent with the W912DR-05-D Area C Semiannual Groundwater Data Report, Round B

11 Section 2.0 Site Setting and History results reported in the Phase I RI report. Two rounds of groundwater sampling were conducted in the winter of 2001 and the winter of 2002 at targeted Area C wells and the southern boundary wells. Area C and southern boundary monitoring wells were targeted to locations with the most significant detections encountered during the Phase I RI. Results generally confirmed the Phase I RI results. There were limited, sporadic VOC detections and widespread arsenic and lead exceedances. However, the dioxin/furan concentrations detected during the Phase I sampling were not repeated in the 2001 sampling (IT, 2002). Monitoring of southern boundary groundwater has been conducted for 14 rounds of sampling from 2002 to A limited number of exceedances have been observed during this period, demonstrating that the groundwater contamination observed within Area C is isolated and of limited extent. During the monitoring period, several LOCs, which are based on current regulatory criteria, have decreased such as vinyl chloride, arsenic, beryllium and lead. As a result, additional wells have been identified with LOC exceedances for these compounds. However, the number of exceedances has decreased over time, indicating a downward trend in the concentrations and suggesting that the contamination is attenuating. Tetrachloroethene (PCE) was detected along the southern boundary during Winter 2010 groundwater sampling at monitoring well SB3-1B at concentrations of 4.4 micrograms per liter (µg/l; January 2010) and 2.6 µg/l (March 2010), which are above the LOC of 1.0 µg/l. It is possible these detections are related to other, upgradient sites at Picatinny Arsenal. Lead has been detected in areas along the southern boundary; however, continued monitoring has shown that the levels are decreasing. Arsenic has been detected in multiple samples in the vicinity of Site 25 at concentrations marginally above LOCs; however, the area in which arsenic is present in exceedance of LOCs is relatively limited in extent, and arsenic has only been detected in two southern boundary monitoring wells (SB2-1A and SB2-2) above the LOC of 3.0 µg/l since Overall, detections of constituents above criteria in groundwater have either been sporadic and isolated at low concentrations (such as RDX, a compound associated with explosives, VOCs and dioxins/furans), potentially related to local background geology (such as the naturally-occurring metals iron, manganese, and aluminum), or not related to site activities occurring at Picatinny Arsenal (such as sodium and chloride). W912DR-05-D Area C Semiannual Groundwater Data Report, Round B

12 Section 3.0 Analytical and Field Sampling Programs 3.0 ANALYTICAL AND FIELD SAMPLING PROGRAMS The proposed LTGM plan consisted of sampling 32 monitoring wells associated with Area C including the 16 southern boundary wells. Figure 4 illustrates the 32 monitoring wells which were proposed to be sampled. During the initial synoptic water level measurements in December 2009, monitoring well could not be located and monitoring well LF-2 could not be opened due to oxidation of the well cap to the galvanized steel casing. Monitoring well , which was formerly located along the skeet range cul-de-sac, may have been destroyed by a snow plow. Therefore, for this sampling event, monitoring wells and LF-2 were not sampled. Sampling of the 30 monitoring wells occurred from June 2010 to August Refer to Section 4.0 for an in depth discussion of the analytical results. A total of 30 monitoring wells were sampled as a part of this semiannual groundwater sampling event. Table 1 summarizes the well designation, the screen interval, hydrogeologic unit, and analytical program implemented for the sampling of these 30 wells. Sixteen of the wells sampled are considered southern boundary wells; and the other 14 wells sampled are associated with specific sites within Area C. Empirical Laboratories, LLC (Empirical) provided all analytical services for this event. Copies of the chain of custody forms and analytical results are provided as Appendix A. All field activities and chemical analyses were conducted in accordance with the Picatinny-Wide Field Sampling Plan (FSP) (ICFKE, 1998a), the Picatinny Facility-Wide Quality Assurance Project Plan (QAPP) (ICFKE, 1998a) and its addendum, and the Picatinny Facility-Wide Health and Safety Plan (HASP) (ICFKE, 1998c). All sampling was conducted in accordance with guidance from the USACE, NJDEP, and USEPA Region 2 including the NJDEP s Field Sampling Procedures Manual (NJDEP, 2005a) and the Technical Requirements for Site Remediation (NJDEP, 2005b). In addition to the chemical analyses, groundwater was also sampled for field parameters, including ph, turbidity, conductivity, temperature, oxidation-reduction potential (ORP), and water level. The sampling data sheets are provided as Appendix B. Well assessment checklists were filled out for each of the 32 monitoring wells which were originally proposed to be sampled as part of this event. These checklists are provided as Appendix C. Because monitoring well no longer exists and there is no suitable replacement, well has been eliminated from the LTGM plan. Subsequent to the sampling event, the steel cap for monitoring well LF-2 was removed from the galvanized steel casing using a welder s torch and chisel. The steel cap was replaced with a threaded PVC cap to prevent a reoccurrence of the oxidation problem. The well (LF- 2) should be sampled during the next semiannual sampling event. It should be noted that monitoring well MW180-1 was proposed to be sampled for dioxins and furans. However, dioxins and furans analyses were inadvertently omitted from this well. Dioxins and furans were not detected in monitoring well MW180-1 during the last sampling event in January W912DR-05-D Area C Semiannual Groundwater Data Report, Round B

13 Section 4.0 Summary of Analytical Results 4.0 SUMMARY OF ANALYTICAL RESULTS The 30 accessible monitoring wells were sampled between June and August A discussion of the results is included in the following text and a summary of results is included as Tables 2 and VOLATILE ORGANIC COMPOUNDS Three VOCs (PCE, cis-1,2-dichloroethene [DCE], and vinyl chloride) were detected in one or more monitoring wells at concentrations in excess of the respective LOCs. PCE (LOC = 1.0 µg/l) was detected in the sample collected from monitoring well SB3-1B (included a duplicate sample) at concentrations of 3.00 µg/l (both samples), which exceed the LOC. Cis-1,2-DCE (LOC = 70 µg/l) was detected in the duplicate sample collected from monitoring well DM19-1 (DM19-1 DUP) at a concentration of 71.6 µg/l, which exceeds the LOC. The average cis-1,2-dce concentration at DM19-1 was 70.0 µg/l, which equals the LOC. Vinyl chloride (LOC = 1.0 µg/l) was detected in the samples collected from monitoring wells DM25-3 (1.66 µg/l), DM25-2 (2.88 µg/l), and DM19-1 (including duplicate, 10.6 µg/l and 10.2 µg/l, respectively) at concentrations which exceed the LOC. PCE was also detected in the sample collected from monitoring well SB4-1 at a concentration of µg/l, which is below the LOC. Cis-1,2-DCE was also detected in the samples collected from monitoring wells DM25-3 (1.20 µg/l), DM25-2 (5.08 µg/l), and DM19-1 (68.3 µg/l), all of which are below the LOC. Nine additional VOCs (benzene, carbon disulfide, toluene, chlorobenzene, dichlorodifluoromethane, ethylbenzene, trichloroethene (TCE), total xylenes, and trans-1,2-dce) were detected in one or more of the monitoring wells at concentrations below LOCs. Benzene (LOC = 1.0 µg/l) was detected in four samples (SB3-1B, SB3-1B DUP, DM25-2, and SB4-1) at concentrations ranging from µg/l to µg/l. Carbon disulfide (LOC = 700 µg/l) was detected in three samples (SB3-1B, SB3-1B DUP, and SB4-1) at concentrations of 3.08, 2.66, and µg/l, respectively. Toluene (LOC = 600 µg/l) was detected in four samples (SB3-1B, SB3-1B DUP, DM25-2, and SB4-1) at concentrations ranging from µg/l to µg/l. Chlorobenzene (LOC = 50 µg/l) was detected in two samples (DM25-3 and DM25-2) at concentrations of 7.02 and µg/l, respectively. Dichlorodifluoromethane (LOC = 1,000 µg/l) was detected in the sample collected from monitoring well DM25-3 at a concentration of µg/l. Ethylbenzene (LOC = 700 µg/l) was detected in the sample collected from monitoring well DM25-2 at a concentration of µg/l. TCE (LOC = 1.0 µg/l) was detected in the sample collected from monitoring well DM25-2 at a concentration of µg/l. Total xylenes (LOC = 1,000 µg/l) were detected in three samples (DM25-2, SB2-3, and SB4-1) at concentrations of 0.473, 0.654, and µg/l, respectively. Trans-1,2-DCE (LOC = 100 µg/l) was detected in two samples (DM19-1 and DM19-1 DUP) at concentrations of 1.12 µg/l and 1.10 µg/l, respectively. 4.2 EXPLOSIVES RDX was the only explosive detected in the groundwater samples at concentrations above the LOC. RDX (LOC = 0.5 µg/l) was detected in the sample collected from monitoring well SB3-1B (included a duplicate sample) at concentrations of 5.95 µg/l (SB3-1B) and 5.84 µg/l (SB3-1B DUP). Six additional explosives (1,3,5-trinitrobenzene, 4-amino-2,6-dinitrotoluene, 4-Nitrotoluene, 2,6- dinitrotoluene, nitrobenzene, and 3-Nitrotoluene) were detected in one or more of the monitoring wells at concentrations below LOCs. 1,3,5-trinitrobenzene (LOC = 1,100 µg/l) was detected in two samples (SB3-1B and SB3-1B DUP) at concentrations of 2.11 and 1.77 µg/l, respectively. 4-amino-2,6- dinitrotoluene (LOC = 73 µg/l) was detected in two samples (SB3-1B and SB3-1B DUP) at concentrations of µg/l (both samples). 4-Nitrotoluene (LOC = 4.2 µg/l) was detected in four samples (SB2-1A, SB3-1B, SB3-1B DUP, and SB4-1) at concentrations of 0.597, 0.381, 0.444, and µg/l, respectively. 2,6-dinitrotoluene (LOC = 10 µg/l) was detected in three samples (SB3-1B, SB3-1B DUP, and SB4-1) at concentrations of 0.220, 3.31, and µg/l, respectively. Nitrobenzene (LOC = 6 µg/l) was detected in two samples (SB3-1B and SB3-1B DUP) at concentrations of 3.07 and 2.64 µg/l, respectively. 3-Nitrotoluene (LOC = 3.7 µg/l) was detected in two samples (SB2-2 and SB4-1) at concentrations of µg/l and µg/l, respectively. W912DR-05-D Area C Semiannual Groundwater Data Report, Round B

14 Section 4.0 Summary of Analytical Results 4.3 METALS Sixteen metals were detected in one or more of the groundwater samples collected. However, only eight of the detected metals (aluminum, chromium, iron, lead, manganese, arsenic, nickel, and sodium) were found at concentrations exceeding the respective LOCs. Arsenic was detected in seven of the 28 samples analyzed for arsenic. All of these detections exceeded the arsenic LOC of 3.0 µg/l. These exceedances included: (11.8 µg/l), MW25-8 (8.04 µg/l), MW180-1 (9.46 µg/l), DM25-2 (5.55 µg/l), DM19-2 (80.3 µg/l), SB2-2 (6.45 µg/l), and C1-B (7.55 µg/l). Chromium was detected in 16 of the 17 samples analyzed for chromium. Of these detections, only two concentrations exceeded the chromium LOC of 70 µg/l. Chromium was detected at concentrations of 105 and 93.7 µg/l in the two groundwater samples collected from monitoring well SB3-1B (including duplicate), respectively. The remaining detected chromium concentrations, which were detected below the LOC, ranged from 2.31 to 21.3 µg/l. Lead was detected in 17 of the 24 samples analyzed for lead. Of these detections, 12 concentrations exceeded the lead LOC of 5.0 µg/l. These exceedances included: SB3-2 (11.5 µg/l), SB3-1B (12.3 µg/l), SB3-1B DUP (14.2 µg/l), MW-17 (21.0 µg/l), MW25-8 (15.2 µg/l), SB1-5 (22.3 µg/l), SB1-3 (20.8 µg/l), SB1-1 (25.9 µg/l), SB1-2 (26.8 µg/l), SB1-6 (14.6 µg/l), SB1-7 (15.1 µg/l), and SB2-1A (6.05 µg/l). The remaining detected lead concentrations, which were detected below the LOC, ranged from 1.85 to 3.99 µg/l. Nickel was detected in 12 of 19 samples analyzed for nickel. Of these detections, only two concentrations exceeded the nickel LOC of 100 µg/l. Nickel was detected at concentrations of 177 and 164 µg/l in the two groundwater samples collected from monitoring well SB3-1B (including duplicate), respectively. The remaining detected nickel concentrations, which were detected below the LOC, ranged from 3.53 to 17.9 µg/l. Aluminum was detected in 14 of the 17 samples analyzed for aluminum. Of these detections, eight concentrations exceeded the aluminum LOC of 200 µg/l. Iron was detected in all 17 samples analyzed for iron. Of these detections, 11 concentrations exceeded the iron LOC of 300 µg/l. Manganese was detected in 15 of the 17 samples analyzed for manganese. Of these, nine concentrations exceeded the manganese LOC of 50 µg/l. Aluminum, iron, and manganese concentrations are elevated due to local geologic conditions. Sodium was detected in all 17 groundwater samples where it was analyzed. Of these detections, eight concentrations exceeded the sodium LOC of 50,000 µg/l. These exceedances included: SB1-3 (318,000 µg/l), SB1-1 (99,000 µg/l), SB1-2 (370,000 µg/l), SB1-6 (229,000 µg/l), SB1-7 (122,000 µg/l), SB2-2 (497,000 µg/l), SB2-1A (102,000 µg/l), and SB3-3 (82,200 µg/l). 4.4 DIOXINS AND FURANS No dioxin or furan compounds were detected in the two groundwater samples collected from monitoring well DM19-1 (including duplicate sample). 4.5 ANIONS Anions detected during analysis of groundwater samples included ammonia, chloride, phosphorus, fluoride, nitrate, sulfate, sulfide, and perchlorate. Chloride results were above the LOC (250 milligrams per Liter [mg/l]) in the samples collected from wells SB1-3 (565 mg/l), SB1-2 (783 mg/l), SB1-6 (417 mg/l), and SB2-2 (964 mg/l). All other concentrations of detected anions were below the applicable LOCs, including perchlorate. Perchlorate (LOC = 5.0 µg/l) was only detected in the sample collected from well SB4-2 at a concentration of µg/l. W912DR-05-D Area C Semiannual Groundwater Data Report, Round B

15 Section 5.0 References 5.0 REFERENCES Dames and Moore Phase I Remedial Investigation Report. Draft Final Document. Prepared for U.S. Army Environmental Center, Aberdeen Proving Ground, Maryland. ICF Kaiser Engineers (ICFKE). 1998a. Picatinny Arsenal Facility-Wide Field Sampling Plan. Prepared for the U.S. Army Corps of Engineers, Baltimore District, September. ICF Kaiser Engineers (ICFKE). 1998b. Picatinny Arsenal Facility-Wide Quality Assurance Project Plan. Prepared for the U.S. Army Corps of Engineers, Baltimore District, December. ICF Kaiser Engineers (ICFKE). 1998c. Picatinny Arsenal Facility-Wide Health and Safety Plan. Prepared for the U.S. Army Corps of Engineers, Baltimore District, February. IT Corporation (IT) Feasibility Study for Site 23. Final. Prepared for U.S. Army Corps of Engineers, Baltimore District. June NJDEP, 2005a. Field Sampling Procedures Manual. August. NJDEP, 2005b. Technical Requirements for Site Remediation, NJAC 7:26E. July. Shaw Environmental, Inc. (Shaw) Record of Decision, Site 23 The Post Farm Landfill. Final. Prepared for U.S. Army Corps of Engineers, Baltimore District. August Shaw Environmental, Inc. (Shaw) Area C Groundwater Feasibility Study. Final. Prepared for U.S. Army Corps of Engineers, Baltimore District. November. Shaw Environmental, Inc. (Shaw) Area C Groundwater Long Term Monitoring Report, Round A. Draft Final. Prepared for U.S. Army Corps of Engineers, Baltimore District. May. W912DR-05-D Area C Semiannual Groundwater Data Report, Round B

16 TABLES W912DR-05-D-0026 Area C Semiannual Groundwater Data Report, Round B

17 Table 1 Area C/Southern Boundary Groundwater Sampling Location and Analysis Summary Screened Interval (feet bgs) Groundwater Depth (feet bgs) Arsenic Beryllium Lead VOCs Dioxins/Furans TAL Metals Explosives Anions Perchlorate Well ID R.I. Site Hydrogeologic Unit SB1-1 Southern Boundary Bedrock - Gneiss X X X X X SB1-2 Southern Boundary Unconfined X X X X X SB1-3 Southern Boundary Upper Semi-Confined X X X X X SB1-5 Southern Boundary Bedrock - Gneiss X X X X X SB1-6 Southern Boundary Unconfined X X X X X SB1-7 Southern Boundary Unconfined X X X X X SB2-1A Southern Boundary Lower Semi-Confined X X X X X SB2-2 Southern Boundary Unconfined X X X X X SB2-3 Southern Boundary Bedrock - Dolomite X X X X X SB3-1B Southern Boundary Bedrock - Dolomite X X X X X SB3-2 Southern Boundary Lower Semi-Confined X X X X X SB3-3 Southern Boundary Unconfined X X X X X SB4-1 Southern Boundary Bedrock - Dolomite X X X X X SB4-2 Southern Boundary Unconfined X X X X X SB4-3 Southern Boundary Upper Semi-Confined X X X X X SB4-4 Southern Boundary Lower Semi-Confined X X X X X MW25-6A Area C Unconfined X X X X MW25-6B Area C Lower Semi-Confined X X X X MW-16 Area C Unconfined X X MW-17 Area C Unconfined X MW25-7 Area C Unconfined X MW25-8 Area C Unconfined X X X DM19-1 Area C Unconfined X X DM19-2 Area C Unconfined X DM25-2 Area C Unconfined X X X DM25-3 Area C Unconfined X X Area C Unconfined X X MW180-1 Area C Unconfined X X C1-A Area C Lower Semi-Confined X C1-B Area C Unconfined X X X Page 1 of 1

18 Table 2 Analytes Detected in Groundwater Area C Sample ID C-1A C-1B DM19-1 DM19-1DUP Analyte Sample Date 7/22/10 6/17/10 6/17/10 7/15/10 7/15/10 Sample Depth LOC LOC Chosen Result Q MDL EQL Result LQ MDL EQL Result LQ MDL EQL Result Q MDL EQL Result Q MDL EQL Volatile Organic Compounds (ug/l) Benzene 1 NJPQL, NJMCL NT NT NT 1 U U Chlorobenzene 50 NJGWQC NT NT NT 1 U U Dichlorodifluoromethane 1000 NJGWQC, FED DW HA NT NT NT 2 U U cis-1,2-dichloroethene 70 NJGWQC, FED MCL, FED DW HA, NJMCL NT NT NT trans-1,2-dichloroethene 100 NJGWQC, FED MCL, NJMCL, FED DW HA NT NT NT 1.12 J J Ethyl benzene 700 NJGWQC, FED MCL, NJMCL, FED DW HA NT NT NT 1 U U Toluene 600 NJGWQC NT NT NT 1 U U Trichloroethene 1 NJGWQC, NJMCL, NJPQL NT NT NT 1 U U Vinyl chloride 1 NJPQL NT NT NT Total Xylenes 1000 NJGWQC, NJMCL NT NT NT 1 U U Metals (ug/l) Arsenic 3 NJPQL U J 3 10 NT NT Lead 5 NJGWQC, NJPQL NT J NT NT Dioxins/Furans (ug/l) NT NT NT ND ND Page 1 of 3

19 Table 2 Analytes Detected in Groundwater Area C Sample ID DM19-2 DM25-2 DM25-3 MW-16 MW-17 Analyte Sample Date 7/15/10 7/15/10 7/15/10 7/15/10 7/22/10 Sample Depth LOC LOC Chosen Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Volatile Organic Compounds (ug/l) Benzene 1 NJPQL, NJMCL NT 0.16 J U NT NT Chlorobenzene 50 NJGWQC NT J NT NT Dichlorodifluoromethane 1000 NJGWQC, FED DW HA NT 2 U J NT NT cis-1,2-dichloroethene 70 NJGWQC, FED MCL, FED DW HA NT J NT NT trans-1,2-dichloroethene 100 NJMCL, FED DW HA, NJMCL NT 1.5 U U NT NT Ethyl benzene 700 NJGWQC, FED MCL, NJMCL, FED DW HA NT J U NT NT Toluene 600 NJGWQC NT J U NT NT Trichloroethene 1 NJGWQC, NJMCL, NJPQL NT J U NT NT Vinyl chloride 1 NJPQL NT NT NT Total Xylenes 1000 NJGWQC, NJMCL NT J U NT NT Metals (ug/l) Arsenic 3 NJPQL J 3 10 NT 10 U 3 10 NT Lead 5 NJGWQC, NJPQL NT NT 3 U NT Dioxins/Furans (ug/l) NT NT NT NT NT Page 2 of 3

20 Table 2 Analytes Detected in Groundwater Area C Sample ID MW180-1 MW25-6A MW25-6B MW25-7 MW25-8 Analyte Sample Date 7/19/10 7/15/10 7/15/10 7/22/10 7/22/10 Sample Depth LOC LOC Chosen Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Volatile Organic Compounds (ug/l) Benzene 1 NJPQL, NJMCL NT 1 U U NT NT Chlorobenzene 50 NJGWQC NT 1 U U NT NT Dichlorodifluoromethane 1000 NJGWQC, FED DW HA NT 2 U U NT NT cis-1,2-dichloroethene 70 NJGWQC, FED MCL, FED DW HA NT 1.5 U U NT NT trans-1,2-dichloroethene 100 NJMCL, FED DW HA, NJMCL NT 1.5 U U NT NT Ethyl benzene 700 NJGWQC, FED MCL, NJMCL, FED DW HA NT 1 U U NT NT Toluene 600 NJGWQC NT 1 U U NT NT Trichloroethene 1 NJGWQC, NJMCL, NJPQL NT 1 U U NT NT Vinyl chloride 1 NJPQL NT 1 U U NT NT Total Xylenes 1000 NJGWQC, NJMCL NT 1 U U NT NT Metals (ug/l) Arsenic 3 NJPQL 9.46 J U U U J 3 10 Lead 5 NJGWQC, NJPQL NT 3 U J NT Dioxins/Furans (ug/l) NT NT NT NT NT LOC = Level of Concern FED MCL = EPA Regional Screening Levels, Maximum Contaminant Level (May 2010) FED DW HA = EPA 2009 Drinking Water Health Advisories (lowest used) NJGWQC = New Jersey Ground Water Quality Standards N.J.A.C. 7:9C, Specific Ground Water Quality Criteria (November 2009) NJGWQC* = New Jersey Ground Water Quality Standards N.J.A.C. 7:9C, Interim Ground Water Quality Criteria (November 2009) NJPQL = New Jersey Ground Water Quality Standards N.J.A.C. 7:9C, Practical Quantitation Limit (November 2009) NJMCL = New Jersey Drinking Water Quality Standards (October 2009) RBC = EPA Regional Screening Levels, Tapwater (May 2010) na = None Available Q = Qualifier U = Compound analyzed but not dectected at a concentration above the reporting limit. J = Estimated value. D = Concentration identified from analysis of the sample at a secondary dilution. R = Rejected result, value should not be used for any purpose. ND = None Detected NT = Not Tested ug/l = micrograms/liter Page 3 of 3

21 Table 3 Analytes Detected in Groundwater Southern Boundary Sample ID SB1-1 SB1-2 SB1-3 SB1-5 SB1-6 SB1-7 Analyte Sample Date 7/20/10 7/20/10 7/20/10 7/20/10 7/20/10 7/20/10 Sample Depth LOC LOC Chosen Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Volatile Organic Compounds (ug/l) Benzene 1 NJPQL, NJMCL 1 U U U U U U Carbon disulfide 700 NJGWQC 1 U U U U U U Tetrachloroethene 1 NJPQL, NJMCL 1 U U U U U U Toluene 600 NJGWQC 1 U U U U U U Total Xylenes 1000 NJGWQC, NJMCL, FED MCL 1 U U U U U U Metals (ug/l) Aluminum 200 NJGWQC J Arsenic 3 NJPQL 10 U U U U U U 3 10 Barium 2000 FED MCL, NJMCL 32.2 J J J 5 40 Cadmium 4 NJGWQC 1.19 J J J J J J 1 5 Calcium None None Chromium 70 NJGWQC 7.55 J J J J J 2 10 Cobalt 100 NJGWQC* 12.5 U U U U U U Copper 1300 NJGWQC, NJMCL 10 U J U J J U 4 10 Iron 300 NJGWQC Lead 5 NJGWQC, NJPQL Magnesium None None Manganese 50 NJGWQC 6.59 J J Nickel 100 NJGWQC, FED DW HA 6.85 J J J J J 3 10 Potassium None None 1650 J J J J J J Sodium NJGWQC Zinc 2000 NJGWQC, FED DW HA J U 5 20 Anions (ug/l) Ammonia 3000 NJGWQC 134 J J MU U U MU Chloride NJGWQC D D D Fluoride 2000 NJGWQC 40 J J U J U Nitrate NJGWQC, FED MCL, NJMCL, FED DW HA J Perchlorate 5 NJGWQC* 0.2 U U U U U U Phosphorus None None 23 J U U J U Sulfate NJGWQC Sulfide None None 2030 U U U U U U Explosives (ug/l) 2,6-Dinitrotoluene 10 NJPQL U U U U U U amino-2,6-Dinitrotoluene 73 RBC UY YU YU YU UY YU Nitrobenzene 6 NJPQL U U U U U U Nitrotoluene 3.7 RBC U U U U U U Nitrotoluene 4.2 RBC U U U U U U RDX 0.5 NJPQL* U U U U U (U) ,3,5-Trinitrobenzene 1100 RBC U U U U U U Page 1 of 3

22 Table 3 Analytes Detected in Groundwater Southern Boundary Sample ID SB2-1A SB2-2 SB2-3 SB3-1B SB3-1BDUP SB3-2 Analyte Sample Date 8/4/10 8/4/10 8/4/10 7/21/10 7/21/10 7/21/10 Sample Depth LOC LOC Chosen Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Volatile Organic Compounds (ug/l) Benzene 1 NJPQL, NJMCL 1 U U U J J U Carbon disulfide 700 NJGWQC 1 U U U U Tetrachloroethene 1 NJPQL, NJMCL 1 U U U U Toluene 600 NJGWQC 1 U U U J J U Total Xylenes 1000 NJGWQC, NJMCL 1 U U J U U U Metals (ug/l) Aluminum 200 NJGWQC J U U J Arsenic 3 NJPQL 10 U J U U U U 3 10 Barium 2000 FED MCL, NJMCL U J J J 5 40 Cadmium 4 NJGWQC 1.14 J J U J J U 1 5 Calcium None None J J Chromium 70 NJGWQC 4.5 J J J 2 10 Cobalt 100 NJGWQC* 12.5 U U U J J U Copper 1300 NJGWQC, NJMCL 6.67 J J J J U 4 10 Iron 300 NJGWQC 53.5 J J J Lead 5 NJGWQC U J Magnesium None None 5000 U U U Manganese 50 NJGWQC 15 U J Nickel 100 NJGWQC, FED DW HA 3.28 J J J 3 10 Potassium None None J J U Sodium NJGWQC D J Zinc 2000 NJGWQC, FED DW HA 20 U J U U J 5 20 Anions (ug/l) Ammonia 3000 NJGWQC U U U U Chloride NJGWQC D Fluoride 2000 NJGWQC U Nitrate NJGWQC, FED MCL 35 J J U U U Perchlorate 5 NJGWQC* 0.2 U U U U U U Phosphorus None None 120 U U U J Sulfate NJGWQC Sulfide None None 2070 U U U D D U Explosives (ug/l) 2,6-Dinitrotoluene 10 NJPQL U U U MJP Z U amino-2,6-Dinitrotoluene 73 RBC U U U PJ PJ U Nitrobenzene 6 NJPQL U U U MNP MP U Nitrotoluene 3.7 RBC U U (U) (U) U Nitrotoluene 4.2 RBC U U MP P U RDX 0.5 NJPQL* U U U MNP MP U ,3,5-Trinitrobenzene 1100 RBC U U U NP U Page 2 of 3

23 Table 3 Analytes Detected in Groundwater Southern Boundary Sample ID SB3-3 SB4-1 SB4-2 SB4-3 SB4-4 Analyte Sample Date 8/5/10 8/3/10 8/3/10 8/3/10 8/3/10 Sample Depth LOC LOC Chosen Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Result Q MDL EQL Volatile Organic Compounds (ug/l) Benzene 1 NJPQL, NJMCL 1 U J U U U Carbon disulfide 700 NJGWQC 1 U J U U U Tetrachloroethene 1 NJPQL, NJMCL 1 U J U U U Toluene 600 NJGWQC 1 U J U U U Total Xylenes 1000 NJGWQC, NJMCL 1 U J U U U Metals (ug/l) Aluminum 200 NJGWQC 176 J U J J Arsenic 3 NJPQL 10 U U U U U 3 10 Barium 2000 FED MCL, NJMCL 26.3 J J J J J 5 40 Cadmium 4 NJGWQC 1.32 J U U J U 1 5 Calcium None None J Chromium 70 NJGWQC 10 U J J J 2 10 Cobalt 100 NJGWQC* 12.5 U U U U U Copper 1300 NJGWQC, NJMCL 10 U U J U 4 10 Iron 300 NJGWQC Lead 5 NJGWQC U U U U Magnesium None None U J Manganese 50 NJGWQC U Nickel 100 NJGWQC, FED DW HA 5.33 J J J 3 10 Potassium None None 3320 J J J U Sodium NJGWQC J Zinc 2000 NJGWQC, FED DW HA 7.51 J U J J 5 20 Anions (ug/l) Ammonia 3000 NJGWQC J U J Chloride NJGWQC Fluoride 2000 NJGWQC 36 J U U Nitrate NJGWQC, FED MCL J J Perchlorate 5 NJGWQC* 1 U U U U Phosphorus None None 120 U U U J Sulfate NJGWQC J Sulfide None None 2180 U J U U U Explosives (ug/l) 2,6-Dinitrotoluene 10 NJPQL U P U U U amino-2,6-Dinitrotoluene 73 RBC U U YU YU YU Nitrobenzene 6 NJPQL U U U U U Nitrotoluene 3.7 RBC U P U U U Nitrotoluene 4.2 RBC U MP U U U RDX 0.5 NJPQL* U U U U U ,3,5-Trinitrobenzene 1100 RBC U (U) U U U LOC = Level of Concern FED MCL = EPA Regional Screening Levels, Maximum Contaminant Level (May 2010) FED DW HA = EPA 2009 Drinking Water Health Advisories (lowest used) NJGWQC = New Jersey Ground Water Quality Standards N.J.A.C. 7:9C, Specific Ground Water Quality Criteria (November 2009) NJGWQC* = New Jersey Ground Water Quality Standards N.J.A.C. 7:9C, Interim Ground Water Quality Criteria (November 2009) NJPQL = New Jersey Ground Water Quality Standards N.J.A.C. 7:9C, Practical Quantitation Limit (November 2009) NJMCL = New Jersey Drinking Water Quality Standards (October 2009) RBC = EPA Regional Screening Levels, Tapwater (May 2010) na = None Available ND = None Detected NT = Not Tested ug/l = micrograms/liter Q = Qualifier U = Compound analyzed but not dectected at a concentration above the reporting limit. J = Estimated value. D = Concentration identified from analysis of the sample at a secondary dilution. R = Rejected result, value should not be used for any purpose. M = Indicates that the sample matrix interfered with the quantitation of the analyte. In dual column analysis the result is reported from the column with the lower concentration. In metals, the qualifier indicates that the parameters MDL/RL have been raised. P = The associated numerical value is an estimated quantity. There is greater than a 40% difference between the two GC columns for the detected concentrations. The higher of the two values is reported unless matrix interference is obvious or for HPLC analysis where the primary column is reported. (U) = Result is considered Non-Detect due to blank contamination. N = The MS/MSD accuracy and/or precision are outside criteria. The predigested spike recovery is not within control limits for the associated parameter. Y = The parameter shows a potential negative bias on a reported concentration due to an ICV or CCV exceeding the lower control limit on the low side. Z-01 = The result is reported from the primary column and was not able to be confirmed on the secondary column due to matrix interference. This result should be considered estimated. Page 3 of 3