2017_October_groundwater_and_surface_water_2007-2017_CBFO.pdf

Ground Water and Surface Water Monitoring of the Prime Hook Lead Shot Site, Prime Hook National Wildlife Refuge, Milton, Delaware

(October 2007-May 2017) Final Report

CBFO-C17-01

Prepared by:

Alfred E. Pinkney and

Carl R. Callahan

U.S. Fish and Wildlife Service Chesapeake Bay Field Office

Environmental Contaminants Program 177 Admiral Cochrane Drive Annapolis, Maryland 21401

Prepared for:

Kristen Thornton Delaware Department of Natural Resources and Environmental Control

Site Investigation and Restoration Branch 391 Lukens Dr.

New Castle, DE 19720

October 2017 ii iii

EXECUTIVE SUMMARY

From 1962 through 1997, the Broadkiln Sportsman’s Club shot trap on a property adjacent to Prime Hook National Wildlife Refuge in Milton, Delaware for almost 40 years. Approximately 22 acres of refuge property fall within the shooting trajectory.

Beginning in 2000 and continuing for several years, the Service evaluated the site and completed an ecological risk assessment. Soil lead cleanup levels of 421 ppm and 7-9 pellets/sq. foot in soil were proposed. The cleanup footprint consisted of 4-5 acres of uplands and wetlands. Due to the cost of the cleanup, it was decided that the upland or capped area (0.8 acres), containing the bulk of the lead, should be removed immediately.

In 2002-2003, the geotextile was removed, eight inches of soil and lead shot were excavated and landfilled, a soil stabilizer was added, and the area was backfilled with clean soil and re-seeded.

Long-term (10-year) assessment of groundwater contamination is needed to determine the need for additional remediation. Ultimately, the objective is to ascertain whether the site can satisfy the requirements for a Closure Plan subject to approval by the State of Delaware, Department of Natural Resources and Environmental Control (DNREC), Division of Air and Waste Management. The groundwater monitoring plan (Appendix A), approved by DNREC in 2006 calls for two years of quarterly sampling followed by eight years of semi-annual sampling. Whole water (W) and 0.45 µm-filtered (F) samples were analyzed for lead, antimony, and arsenic. These two metals are the primary alloys added to lead (antimony at about 2.7% and arsenic about 0.2%). Here we report the results of sampling from October 2007 through May 2017 (Years 1 through 10).

Arsenic and antimony were never detected in any groundwater samples. Lead was detected in samples from at least one of the three wells (DZ4, DZ5, or DZ6) in every collection through 2015. Well DZ6 had detectable lead concentrations in unfiltered water in every collection, with concentrations ranging from 3.7 µg/L to 15.5 µg/L. Lead was detected in well DZ5 in October 2007, April 2008, October 2008, February 2009, April 2009, and October 2009. Concentrations ranged from 2.2 µg/L to 6.0 µg/L. Lead was first detected in DZ-4 in April 2010 and again in April 2011 ranging from 3.0 ug/L to

11.5 ug/L in unfiltered water collections. Lead in whole water was only detected once in the upgradient well (3.2 ug/L in October 2008) and twice in the downgradient well (3.2 µg/L in January 2008 and 3.0 µg/L in October 2008). No detections were reported in filtered samples from the upgradient or downgradient wells. In general, filtered samples had substantially lower lead concentrations than unfiltered samples from the same sampling event. In the final collection in May 2017, there were no samples with detectable lead.

Since there was only a single hit (3.2 µg/L) in the upgradient or “background” well, there is no need for a statistical comparison with background. Trace concentrations of lead were frequently detected in well DZ6 (at about 3 to 6 µg/L in filtered samples) and rarely in wells DZ5 and DZ4 (at similar concentrations). This suggests that some residual lead from the soil contamination may persist in the groundwater, although the final sampling in May 2017 showed no detectable lead. Furthermore, the lack of consistent detection in iv the downgradient sample indicates that the extent and magnitude of the groundwater contamination is limited. In addition, the filtered concentrations were well below 15 µg/L, Delaware’s Maximum Contaminant Level for drinking water. Although the shallow aquifer being sampled is not a drinking water aquifer, the low level suggests a lack of substantial contamination.

Surface water was sampled (W) and (F) for lead, antimony, and arsenic. In April 2010, October 2010, April 2011, June 2013, and March 2014, we attempted to sample from four locations (Surf 1–4). In addition, a reference location, Fred’s Pond, was sampled in April 2010. Two other wetland locations, Surf 5 and 6, were sampled in December 2014 to increase the area covered. At location Surf 2, a one meter wide and 0.5 m deep seep, there was rarely enough water and a piezometer was installed in 2013 to allow the location to be sampled. This location is near the edge of the forested wetland and was within the area that was littered with lead shot on the soil surface. In December 2015, two more locations, Surf 7 and 8, were added and all 8 locations were sampled for lead only.

Lead was detected in every filtered and unfiltered sample in the April 2010 collection, including the samples from Fred’s Pond. Lead concentrations were highest at Surf 2 (8230 µg/L unfiltered, 1960 µg/L filtered) which is the seep on the edge of the forested wetland which is loaded with lead pellets. The filtered concentration at the three forested wetland locations closest to the shooting range were 779 to 1960 µg/L, far exceeding the chronic ambient water quality criterion of 3.2 µg/L (at a hardness of 100 mg/L CaCO3).

Filtered concentrations were far lower at Surf 4 (5.5 µg/L) and Fred’s Pond (11.2 µg/L).

In the October 2010, April 2011, and March 2014 sampling events, a similar pattern was found in which lead concentrations from Surf 1 and 3 far exceeded the ambient water criterion, whereas the concentration in Surf 4 was about an order of magnitude lower but still above the criterion. It was not possible to sample Surf 2 on these events because it was dry. In the December 2014 sampling event, the filtered lead concentrations were:

Surf 1: 65.2 µg/L Surf 3: 292 µg/L, Surf 4: 74.1, Surf 6: 43.9 µg/L. Lead was not detected in the filtered sample at Surf 5. All detected concentrations exceeded the chronic ambient water quality criterion of 0.93 µg/L.

Antimony, for which there is no chronic criterion, was detected in unfiltered samples from Surf 1-3 in April 2010, Surf 1 and 3 in October 2010, Surf 3 in April 2011, Surf 3 in June 2013, Surf 2 and 3 in March 2014, and Surf 1 and 3 in December 2014. The only detection in filtered samples was from Surf 3 in April 2010 at 15.8 µg/L; Surf 2 (24.3 µg/L) and Surf 3 (8.5 µg/L) in March 2014; and Surf 3 in December 2014 (6.3 µg/L).

Arsenic was also detected in unfiltered samples from these same locations. Arsenic was detected in filtered samples from Surf 2 and 3 in April 2010, Surf 3 in April 2011, Surf 1 in June 2013, and Surf 1-3 in March 2014. None of the concentrations exceeded the ambient water quality criterion of 150 µg/L.

The area immediately surrounding Site 2 had what appeared to be the highest deposition of exposed lead shot in the forested wetland. Due to this finding, lead shot was excavated from this area by a team of USFWS biologists in October, 2011. Three 55 gallon drums containing lead shot contaminated soil were removed from this area and taken to a v hazardous waste landfill by Potomac Environmental Inc. in December 2011; another 3 drums were excavated during 2014 and removed in January 2015. Shot remains visible in the wetlands and we do not recommend further excavation by shovel because of the disposal expense. Instead, an Environmental Evaluation/Cost Assessment (EE/CA) of the forested wetland was initiated in early 2017 with results expected by December 2017.

The EE/CA included surface and subsurface soil and sediment sampling and surface water sampling in dry and wet periods. Results will be used to recommend a possible cleanup action.

ACKNOWLEDGMENTS

We thank Sherry Krest for assisting with developing the plan and administering the project. Peter McGowan, Sherry Krest, Susan Frey and Robbie Callahan assisted with the sampling.

C:\Users\fpinkney\Documents\transfer\USR\primehook groundwater\2012 monitoring report to DNREC\2014 report\2014 Ground Water and Surface Water Monitoring of the Prime Hook Lead Shot Site.docx vi vii

TABLE OF CONTENTS

EXECUTIVE SUMMARY ......................................................................................................................... iii

ACKNOWLEDGMENTS ............................................................................................................................ v

TABLE OF CONTENTS ........................................................................................................................... vii

LIST OF TABLES ...................................................................................................................................... vii

LIST OF FIGURES ................................................................................................................................... viii

LIST OF APPENDICES ........................................................................................................................... viii

INTRODUCTION

METHODS

Groundwater Well Locations Surface Water Locations Well Sampling Procedures Surface Water Sampling Procedures Analytical Procedures Data analysis Investigation-Derived Waste (IDW)

RESULTS AND DISCUSSION

General Groundwater Well Samples Surface water

RECOMMENDATION

REFERENCES

TABLES

APPENDIX A

APPENDIX B

LIST OF TABLES

Table 1. Well locations and depths

Table 2. Surface water locations and description.

Table 3. Sampling dates

Table 4. Summary of positive analytical results of lead (µg/L) for groundwater samples at the Prime Hook Lead Shot Site.

viii

Table 5. Summary of positive analytical results for lead (µg/L) in surface water samples at the Prime Hook Lead Shot Site.

Table 6. Summary of positive analytical results for antimony (µg/L) in surface water samples at the Prime Hook Lead Shot Site.

Table 7. Summary of positive analytical results for arsenic (µg/L) in surface water samples at the Prime Hook lead site.

LIST OF FIGURES

Figure 1. Map showing the general location of the Prime Hook Lead Shot Site (drop zone).

Figure 2. Map of the Prime Hook Lead Shot Site showing the groundwater wells (DZ4-6, UG1, and DG9) and surface water sampling sites (Surf 1 W through 4 W).

LIST OF APPENDICES

Appendix A Prime Hook Groundwater Monitoring Plan (2006)

Appendix B Standard Operating Procedures

INTRODUCTION

Beginning in the early 1960s, and continuing through 2000, the Broadkiln Sportsman’s Club shot trap on a property adjacent to Prime Hook National Wildlife Refuge in Milton, Delaware (Figure 1). Approximately 22 acres of refuge property fall within the shooting trajectory. Portions of this area received significant amounts of lead shot deposition through the years. In the late 1990’s, the Sportsman’s Club proposed that the Service trade contaminated refuge property for an equal acreage of club land outside the shooting trajectory. To assist in the decision of whether or not to proceed with the land transfer, the Service collected soil samples to determine the extent of lead shot deposition and lead soil concentrations on a 5-acre parcel that was proposed to be transferred to the Sportsman’s Club (Murphy 1999).

Murphy (1999) found that surface soils on refuge and private lands within the Broadkiln Sportsman’s Club shooting trajectory contain quantities of lead shot that greatly exceed the density of 1 shot pellet per square foot that has been found to result in increased availability to waterfowl (Jensen and Lound 1959). Pellet counts from samples collected within the shooting trajectory ranged from 49 to 57,868 shot/ft2 with a mean of 6,673 shot/ft2. Birds ingest lead shot into their gizzards as grit to aid in the digestion of food.

Lead shot ingestion is a significant cause of mortality and sublethal effects in many avian species (Eisler 1998).

Soil lead concentrations within the shooting trajectory were found to exceed background levels and guidelines that were developed to protect human health and the environmental (NJDEP 1987; CCME 1997; Richardson 1987; USEPA 1995). Soil lead chemistry results from a total of four samples collected from the site ranged from 128 to 2,745 mg/kg with a mean of 1,056 mg/kg. Results from all four sample plots greatly exceeded the 3.2 mg/kg concentration found in a reference sample collected from an area outside the shot trajectory, as well as other background data.

In FY 2000, the USFWS Division of Refuges funded the first year of what was expected to be a two-year Refuge Cleanup Project. The objectives were to delineate the magnitude and extent of soil and sediment contamination with lead and lead. The Service asked the Shooting Club to discontinue shooting on Refuge Property and they cooperated.

Using Refuge Cleanup funds, delineation activities were completed in May 2000, and liner emplacement was completed in early July 2000. A Preliminary Assessment / Site Investigation report was completed in March 2001 by a USFWS contractor (Harding ESE 2001). The Service completed an ecological risk assessment and set cleanup goals of 421 ppm lead and 7–9 pellets/sq. ft (Guy et al. 2004). The cleanup footprint consisted of 4-5 acres of uplands and wetlands. Due to the cost of the cleanup, it was decided that the upland or capped area (0.8 acres), containing the bulk of the lead, should be removed immediately. In 2002-2003, the geotextile was removed, eight inches of soil and lead shot were excavated and landfilled, a soil stabilizer was added, and the area was backfilled with clean soil and re-seeded.

In 2000, the USGS installed and sampled seven piezometers at the site and found elevated lead concentrations up to 965 mg dissolved lead/liter in groundwater beneath the site. Due to site conditions—high flushing rate and shallow aquifer—it was decided not to actively treat the groundwater but rather to monitor and evaluate the concentrations over time.

Long-term assessment of groundwater contamination is needed to determine the need for additional remediation. Ultimately, the objective is to ascertain whether the site can satisfy the requirements for a Closure Plan subject to approval by the State of Delaware, Department of Natural Resources and Environmental Control (DNREC), Division of Air and Waste Management.

In 2006, the groundwater monitoring plan (Appendix A) was approved by DNREC that calls for two years of quarterly sampling followed by eight years of semi-annual sampling. In addition to lead, shot pellets are highest in antimony (~2.7%) and arsenic (0.2%; Mann et al. 1994), which were also monitored. In order to effectively monitor the groundwater concentrations three new groundwater wells were installed in 2006 within the restored area (Shaw Engineering Inc. 2006; Figure 2). A new background well and a new downgradient well were installed in June 2007 (BrightFields Inc. 2007), close to older wells at these locations installed by USGS (Soeder and Miller 2003). All five wells are constructed similarly with four inch diameter steel protective casing and bentonite poured at the base.

Because lead shot remains on the surface of the forested wetland and the proximity of an unnamed stream to the site, surface water contamination is also a concern. Thus, surface water sampling was initiated in April 2010 and the results of all surface water sampling events are reported here.

Here we report the results of groundwater and surface water sampling, covering the period of October 2007 through May 2017. Sampling was conducted quarterly for years 1 and 2, semiannually for years 3 through 5, and annually for years 6 through 10. In addition to the groundwater and surface water sampling, we also report on our efforts to remove surface pellets from the edge of the forested wetland (Near Surf 2, Figure 2).

METHODS

Groundwater Well Locations

A total of five shallow wells have been sampled (Figure 2). These consist of three wells within the removal area (DZ4, DZ5, and DZ6), one background well (UG1R), and one downgradient well (DG9R). Shaw (2006) and BrightFields, Inc. (2007) describe the installation of these wells. Latitude and longitude and depths of these wells are described in Table 1.

Surface Water Locations

Seven surface water locations have been sampled (Figure 1 for Fred’s Pond, Figure 2 for Surface 1-6). Surf 1 (38.82335 N, 75.28480 W) is located twenty feet into water from well DG9R. Surf 2 (38.82406 N, 75.28495 W) is a small depression on the edge of the forested wetland near well DZ6 where a substantial amount of lead shot is visible on the ground. Surf 3 (38.82372 N, 75.28480 W) is into the reeds for measurement away from any lead shot exposed on the surface. Surf 4 (38.822249 N, 75.28537 W) was in the wetland in the woods behind UG1R. Fred’s Pond 1(FP1) (38.83205 N, 75.25558 W) was collected by wading out into the edge of the pond. Surf 5 (38.82216 N, 75.28532 W) is about 20 m upgradient of Surf 4. Surf 6 38.82216 N, 75.28483 W) is located about 30 meters upgradient of Surf 1.

Well Sampling Procedures

Groundwater sampling was conducted according to Standard Operating Procedures prepared by the U.S. Environmental Protection Agency’s Emergency Response Team (SOP Number 2007, USEPA 1995) and the U.S. Geological Survey’s National Field Manual for the Collection of Water Quality Data (USGS 1999). Procedures used at Prime Hook are documented as CBFO Standard Operating Procedure 141 (Appendix B).

As described in Section 4.2 of USGS (1999), wells were purged by removing three volumes of standing water until pH, temperature, conductivity, and turbidity readings were stable. A Solinst peristaltic pump with silicone pump tubing and LDPE well tubing was used. Water level was recorded with a Solinst brand Mini 101 Water Level Meter.

Washing procedures for the water level meter before the first sampling and between sampling dates included soaking in phosphate-free liquid laboratory detergent followed by a rinse with deionized water, soaking in 10% nitric acid, and a final rinse with deionized water. A well volume was calculated first by subtracting the depth to water from the total depth of the well and multiplying the height by the area of a cross section of the well. To minimize contamination, tubing was disposed after each sampling event.

Samples were pumped directly into precleaned polyethylene bottles supplied by the analytical laboratory, which contained several ml of concentrated nitric acid as a preservative. After the requisite volume of unfiltered water is collected, an in-line Millipore (Catalog number: GWSC04510) 0.45 µm polyethersulfone filter was installed and an appropriate volume of filtered sample was collected into a second polyethylene bottle. Quality assurance procedures are based on USEPA Region III protocols and included the analysis of field and filter blanks, instrument blanks, field duplicates, and matrix spike duplicates. Samples were stored in iced coolers and shipped (on ice) as soon as possible to the analytical laboratory (TestAmerica Inc., Edison, NJ). Chain of custody was maintained according to CBFO Standard Operating Procedure 102 (Appendix B).

Surface Water Sampling Procedures

Surface water was collected in the laboratory-supplied precleaned polyethylene bottles by immersing them with a nitrile-gloved hand just below the surface. The bottles were filled about ¾ to the top to avoid displacing any of the concentrated nitric acid preservative.

Filtered samples were first collected as described above then a peristaltic pump was used to pump the collected sample through an inline 0.45 µm polyethersulfone filter into precleaned polyethylene bottles. Samples were maintained in an identical manner as the groundwater samples.

Analytical Procedures

Samples were analyzed by TestAmerica (formerly Severn Trent Laboratories), Edison, NJ (STL-Edison) according to EPA SW846 Method 6010B which utilizes Inductively Coupled Plasma Spectroscopy. According to Bob Schulte (DNREC, Division of Air and Waste Management, 302-395-2600), the laboratory is certified by the State of Delaware for groundwater analysis. Certification is also provided in the quote with instrument quantitation limits of 8.68 µg/L for antimony, 4.70 µg/L for arsenic, and 2.70 µg/L for lead. A copy of the STL quote is included in Appendix A.

Data analysis

Filtered groundwater concentrations were compared against the Delaware Water Quality Criteria for Protection of Human Health (DNREC 2004). These are the primary Maximum Contaminant Levels for drinking water of 6 µg/L for antimony, 10 µg/L for inorganic arsenic, and 15 µg/L for lead.

Filtered surface water concentrations were compared against the chronic criteria listed in the Delaware Water Quality Standards (http://regulations.delaware.gov/AdminCode/title7/7000/7400/7401.pdf). The chronic criteria are four-day average concentrations not to be exceeded more than once in any three-year period. The criteria for lead is hardness-based. Measurements at the site were frequently about 40 mg/L calcium carbonate. Thus the calculated chronic criterion using a value of 40 mg/L and corrected for the dissolved fraction (0.92) yields a concentration of 0.93 µg/L (http://regulations.delaware.gov/AdminCode/title7/7000/7400/7401.pdf).

The chronic criterion for trivalent arsenic is 150 µg/L, which U.S. EPA (2009) applies to total arsenic. No aquatic life criteria have been promulgated for antimony.

Investigation-Derived Waste (IDW)

Purge water (approximately 2 gallons per well) from the sampling wells was stored on-site in approved 5-gallon high density polyethylene pails with screw cap lids. Since the sampling results documented very low lead concentrations, the contents were disposed on-site by pouring on the ground.

Removal of lead shot at the edge of the wetlands

Shovels were used to remove visible lead pellets at the edge of the wetlands near Surf 2 in October 2011, March 2014 and September 2014. A total of six 55-gallon drums of lead-shot contaminated soil have been removed.

http://regulations.delaware.gov/AdminCode/title7/7000/7400/7401.pdf

Piezometer installation

Al Rizzo installed a piezometer at Surf 2 in June 2013. The first sample was collected in March 2014, a second in December 2014, and a third in December 2015.

RESULTS AND DISCUSSION

General

On every occasion, the laboratory certified that the samples arrived in good condition and at a temperature of 6 °C or less which met the guidance. The laboratory certified the quality of the results and did not note any quality assurance anomalies in any of the samples. In addition, there were no detections in any of the field and filter blanks. The quality assurance data are included in the electronic copies of the complete laboratory data package, which are available upon request. Based on the results and DNREC approval, the schedule for sampling of groundwater has been quarterly for years 1 and 2, semiannually for years 3 through 5, and annually for years 6 through 10. Previous reports are Pinkney (2010) and Pinkney and Callahan (2012, 2014, and 2017).

Because the lead concentrations at all wells has been low (<15 µg/L), IDW has been stored on-site between sampling events. On the next sampling event, the IDW is disposed on-site by pouring it on the ground at least 10 feet from the wells. A composite sample from the IDW from the April 22, 2009 sampling had no detectable concentrations of the target analytes.

Groundwater Well Samples

Antimony was never detected in any of the samples. Arsenic was detected in one sample (DZ4W) at 5.8 µg/L on April 13, 2010. Arsenic was not detected in the filtered sample from this well. This does not exceed the Delaware criterion of 10 µg/L for drinking water.

Lead was detected in at least one of the three wells (DZ4, DZ5, or DZ6) in every quarter in Years 1 and 2 and in all semi-annual sampling except for October 26, 2010 (Table 4).

Lead was frequently detected in well DZ6 with concentrations ranging from 3.7 µg/L to

15.5 µg/L. Lead was detected in well DZ5 in October 2007, April 2008, October 2008, February 2009, April 2009, and October 2009. Concentrations ranged from 2.2 µg/L to

6.0 µg/L. Lead was first detected in DZ-4 in April 2010, again in April 2011, and in July 2013 at concentrations ranging from 3.0 ug/L to 11.5 ug/L in unfiltered water collections.

Lead was only detected once in the upgradient well (3.2 ug/L in October 2008) and twice in the downgradient well (3.2 µg/L in January 2008 and 3.0 µg/L in October 2008).

Filtered samples had consistently lower lead concentrations compared with the unfiltered sample collected at the same well in the same collection (Table 4). The highest concentration in a filtered well sample (DZ6) was 5.6 µg/L.

In the three sampling rounds since the Pinkney and Callahan (2012) report, the highest lead detection in an unfiltered groundwater sample was 6.1 µg/L from well DZ6 on March 26, 2014. The highest lead detection in a filtered water sample was 5.2 from Well DZ6 on September 27, 2012. In the most recent round, May 2017, no detectable lead was reported in any well samples.

Since there was only a single hit (3.2 µg/L) in the upgradient or “background” well, there is no need for a statistical comparison with background. Trace concentrations of lead were frequently detected in well DZ6 (at about 3 to 6 µg/L in filtered samples) and rarely in wells DZ5 and DZ4 (at similar concentrations). This suggests that some residual lead from the soil contamination may persist in the groundwater, although the final sampling in May 2017 showed no detectable lead. Furthermore, the lack of consistent detection in the downgradient sample indicates that the extent and magnitude of the groundwater contamination is limited. In addition, the filtered concentrations were well below 15 µg/L, Delaware’s Maximum Contaminant Level for drinking water. Although the shallow aquifer being sampled is not a drinking water aquifer, the low level suggests a lack of substantial contamination.

Piezometer Sample

Two rounds of sampling (March 2014 and December 2014) were conducted from the piezometer at Surf 2 W (Figure 2). In March 2014, in the unfiltered sample, lead was detected (109 µg/L), antimony was not detected, and arsenic was detected (6.5 µg/L).

None of the three metals was detected in the filtered sample. In December 2014, lead was detected at 19.6 µg/L unfiltered and 5.1 µg/L filtered.

Surface water

Lead was detected in all of the unfiltered samples at all locations including Fred’s Pond (Table 5). Concentrations were highest at Surf 2 (8230 µg/L unfiltered, 1960 µg/L filtered; April 2010; 106,000 µg/L unfiltered, 18,100 µg/L filtered; March 2014) which is the seep on the edge of the forested wetland which is loaded with lead pellets. This seep was dry and could not be sampled in the other sampling events.

Concentrations were next highest at Surf 3. The filtered concentrations ranged from 292 to 6990 µg/L (Table 5). This location is 22.8 meters from the edge of the wetland near groundwater well DZ4 (Figure 2). Contamination was less at Surf 1, with filtered concentrations ranging from 45.6 to 521 µg/L. This location is about 10 meters from downgradient well DG9 and 30.5 meters from the edge of the forested wetland.

Somewhat lesser contamination was detected at Surf 4, which is 87.5 meters from the upgradient well. Filtered lead concentrations ranged from 5.2 to 74.1 µg/L. The single Fred’s Pond sample (April 2010) had a filtered concentration of 11.2 µg/L. In the most recent sampling (December 2014) filtered concentrations were as follows: Surf 1: 65.2 µg/L Surf 3: 292 µg/L, Surf 4: 74.1, Surf 6: 43.9 µg/L. Lead was not detected in the filtered sample at Surf 5.

All detected lead concentrations including those at Fred’s Pond exceeded the chronic ambient water quality criterion of 0.93 µg/L at the site hardness of 40 mg/L CaCO3. The greatest concern is in the seep (Surf 2) which may be due to loading from the exposed pellets. However, the large exceedance of the chronic water quality criterion at locations 1 and 3 and the lower, but still excessive concentration in Surf 4 and Surf 6 suggests the need for further sampling to confirm and estimate the extent of contamination.

Antimony, for which there is no chronic criterion, was detected in unfiltered samples from Surf 1, 2, and 3 in April 2010, Surf 1 and Surf 3 in October 2010, Surf 3 in April 2011, Surf 3 in June 2013, Surf 1, 2, and 3 in March 2014, and Surf 1 and 3 in December 2014 (Table 6). The only detection in filtered samples was from Surf 3 in April 2010, Surf 2 and 3 in March 2014, and Surf 3 in December 2014. The highest filtered concentration was in Surf 2 at 24.3 µg/L, probably as a result of the large number of pellets found adjacent to the sampling location.

Arsenic was detected in unfiltered samples from at least one location in all the sampling events. Arsenic was detected in filtered samples from Surf 2 and 3 in April 2010, Surf 3 in April 2011, Surf 1 in June 2013, and Surf 1, 2, and 3 in March 2014. The highest filtered concentration was in Surf 2 at 46.7 µg/L, probably as a result of the large number of pellets adjacent to the sampling location. None of the concentrations exceeded the ambient water quality criterion of 150 µg/L (Table 7).

Shoveling of Lead

Lead shot was excavated using hand shovels from the area near Surf 2 by a team of USFWS biologists in October, 2011. Three 55 gallon drums containing lead shot contaminated soil were removed from this area and disposed at a hazardous waste landfill by Potomac Environmental Inc. in December 2011. Further removal was conducted in October 2013 and March 2014, with 3 additional drums disposed in September 2014.

RECOMMENDATION

The results have shown that groundwater contamination at the site is minimal. The ten years of sampling show that only trace amounts of lead are detectable in the groundwater samples, and usually in only one of the three wells on the remediated area. In the most recent round, May 2017, no detectable lead was reported in any well samples.

Surface water lead contamination in the wetland is a greater concern. Multiple samples were well above the state standard of 0.93 µg/L. Therefore, an Environmental Evaluation/Cost Assessment (EE/CA) of the forested wetland was initiated in early 2017 with results expected by December 2017. The EE/CA included surface and subsurface soil and sediment sampling and surface water sampling in dry and wet periods. Results will be used to recommend a possible cleanup action.

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http://www.epa.gov/ost/criteria/wqctable

U.S. Geological Survey (USGS) 1999. National field manual for the collection of water-quality data: U.S. Geological Survey Techniques of Water-Resources Investigations.

http://water.usgs.gov/owq/FieldManual/mastererrata.html

TABLES

Table 1. Well locations and depths

Well number Latitude Longitude Depth (ft)

DZ4 38.82376 -75.28521 12.82

DZ5 38.82375 -75.28548 12.56

DZ6 38.82405 -75.28516 12.60

DG9 38.82341 -75.28489 12.70

UG1 38.82292 -75.28590 12.68

PIEZ 38.82406 -75.28495 ~3

Table 2. Surface water locations and descriptions

Surface water

ID

Latitude Longitude Site Description

Surf 1 38.82335 -75.28480 Twenty feet into woods from DG9R well Surf 2 38.82406 -75.28495 Edge of woods with lots of lead shot on the surface of the ground; Piezometer installed here for groundwater sampling

Surf 3 38.82372 -75.28480 In reeds away from any lead shot exposed on the surface

Surf 4 38.822249 -75.28537 Wetland stream in woods well behind

UG1R

Surf 5 38.82216 -75.28532 Wetland stream in woods about 20 m upgradient of Surf4

Surf 6 38.82216 -75.28483 Wetland stream in woods about 30 m upgradient of Surf 1

Surf 7 38.82329 -75.28500 Wetland stream southernmost sample about 40 m from edge of upland

Surf 8 38.82294 -75.28499 Wetland stream about 20 m southwest of

DG-9

FP1W 38.83205 -75.25558 Edge of Fred’s Pond

Table 3. Sampling dates. Years are fiscal years, starting with FY 08 as Year 1.

Date Yr Ground

Water Surface Water

Date Yr Ground Water

Surface Water

10/10/2007 1 X 9/27/2012 5 X 1/15/2008 1 X 7/31/2013 6 X 4/29/2008 1 X 3/26/2014 7 X X 7/1/2008 1 X 12/1/2014 8 X X 10/14/2008 2 X 12/16/2015 9 X X 2/19/2009 2 X 5/17/2017 10 X 4/22/2009 2 X 7/20/2009 2 X 10/20/2009 3 X 4/13/2010 3 X X 10/26/2010 4 X X 4/27/2011 4 X X 12/13/2011 5 X

Table 4. Summary of positive analytical results of lead (µg/L) for groundwater samples.

No analytes were detected in the October 26, 2010 or May 17, 2017 events. No filtered samples exceeded the state drinking water standard of 15 µg/L.

October 10, 2007 April 13, 2010 Unfiltered Filtered Unfiltered Filtered

DZ5W 2.7 DZ4W 11.5

DZ6W 8.1 DZ6F 4.1 DZ4DW 4.5

DZ6DW 8.7 DZ6DF 4.2 DZ6W 15.5

January 15, 2008 April 27, 2011 Unfiltered Filtered Unfiltered Filtered

DZ6W 11.6 DZ4W 3.0

DZ6DW 10.8 DZ6DF 2.8 DZ6W 4.7

DG9W 3.2

April 29, 2008 December 13, 2011 Unfiltered Filtered Unfiltered Filtered

DZ5W 4.8 DZ5F 3.1 DZ6W 7.3 DZ6F 5.3

DZ5DW 3.9 DZ5DF 3.4

DZ6W 9.4 DZ6F 5.6

July 1, 2008 September 27, 2012 Unfiltered Filtered Unfiltered Filtered

DZ6W 3.2 DZ6DW 4.9 DZ6DF 5.2

DZ6DW 3.7

October 14, 2008 July 31, 2013 Unfiltered Filtered Unfiltered

DZ5W 2.3 DZ4W 4.6

DZ6W 4.6 DZ6F 2.5

DG9W 3

UG1W 3.2

February 19, 2009 March 26, 2014 Unfiltered Filtered Unfiltered

DZ5W 3.5 DZ6W 6.1

DZ6W 8.2 PIEZ W 109

April 22, 2009 December 1, 2014 Unfiltered Filtered Unfiltered Filtered

DZ5W 2.2 DZ6W 5.9

DZ6W 5.1 DZ6F 3.1 DZ6DW 5.8 DZ6F 3.1

PIEZ W 19.6 PIEZ F 5.1

July 20, 2009 December 16, 2015 Unfiltered Filtered Unfiltered Filtered

DZ6W 5.2 DZ6F 4.6 PIEZ W 16.3

DZ6DW 3.9 DZ6DF 3.2

October 20, 2009 Unfiltered Filtered

DZ5W 6.0 DZ5F 2.9

DZ5DW 5.3

DZ6W 5.4 DZ6F 5.3

Table 5. Summary of positive analytical results for lead (µg/L) in surface water samples at the Prime Hook Lead Shot Site. Filtered samples exceeding the state chronic ambient water quality standard of 0.93 µg/L are in bold.

April 13, 2010 December 16, 2015 Unfiltered Filtered Unfiltered Filtered

Surf 1W 200 Surf 1F 97.0 Surf 1W 43.4 Surf 1F 36.9 Surf 2W 8230 Surf 2F 1960 Surf 2W 1880 Surf 2F 1750 Surf 3W 465 Surf 3F 779 Surf 3W 12700 Surf 3F 10400 Surf 4W 13.1 Surf 4F 5.5 Surf 4W 65.0 Surf 4F 24.0 FP1W 9.9 FP1F 11.2 Surf 5W 5.8 Surf 5F 5.3

October 26, 2010 Surf 6W 108 Surf 6F 76.6 Unfiltered Filtered Surf 7W 59.7 Surf 7F 57.1

Surf 1W 4050 Surf 1F 385 Surf 8W 199 Surf 8F 107 Surf 3W 2170 Surf 3F 828 Surf 4W 53.5 Surf 4F 11.7

April 27, 2011 Unfiltered Filtered

Surf 1W 60.3 Surf 1F 45.6 Surf 3W 12000 Surf 3F 3090 Surf 4W 17.4 Surf 4F 5.2

June 25, 2013 Unfiltered Filtered

Surf 1W 597 Surf 1F 506 Surf 3W 7170 Surf 3F 1760 Surf 4W 74.6 Surf 4F 21.2

FP1W 5.5

March 26, 2014 Unfiltered Filtered

Surf 1W 858 Surf 1F 521 Surf 2W 106000 Surf 2F 18100 Surf 3W 15000 Surf 3F 6990 Surf 4W 135 Surf 4F 52.9

December 1, 2014 Unfiltered Filtered

Surf 1W 193 Surf 1F 65.2 Surf 3W 3260 Surf 3F 292 Surf 4W 227 Surf 4F 74.1 Surf 5W 21.7 Surf 6W 158 Surf 6F 43.9

Table 6. Summary of positive analytical results for antimony (µg/L) in surface water samples at the Prime Hook Lead Shot Site.

April 13, 2010 Unfiltered Filtered

Surf 1W 5.3 Surf 2W 130 Surf 3W 18.5 Surf 3F 15.8

October 26, 2010 Unfiltered Filtered

Surf 1W 35.8 Surf 3W 16.5

April 27, 2011 Unfiltered Filtered

Surf 3W 162 June 25, 2013

Unfiltered Filtered Surf 3W 57.2

March 26, 2014 Unfiltered Filtered

Surf 1W 12.2 Surf 2W 593 Surf 2F 24.3 Surf 3 W 137 Surf 3F 8.5

December 1, 2014 Unfiltered Filtered

Surf 1W 6.1 Surf 3W 35.2 Surf 3F 6.3

Table 7. Summary of positive analytical results for arsenic (µg/L) in surface water samples at the Prime Hook lead site. No filtered samples exceeded the state chronic ambient water quality criteria of 150 µg/L.

April 13, 2010 Unfiltered Filtered

Surf 1W 5.1 Surf 2W 226 Surf 2F 8.9 Surf 3W 21.6 Surf 3F 21.5

October 26, 2010 Unfiltered Filtered

Surf 1W 24.3 Surf 3W 10.4

April 27, 2011 Unfiltered Filtered

Surf 3W 27.6 Surf 3F 6.9 June 25, 2013

Unfiltered Filtered Surf 1W 6.9 Surf 1F 3.7 Surf 3W 27.2

March 26, 2014 Unfiltered Filtered

Surf 1W 14.4 Surf 1F 3.7 Surf 2W 616 Surf 2F 46.7 Surf 3W 30.8 Surf 3F 7.7 Surf 4W 7.0

December 1, 2014 Unfiltered Filtered

Surf 3W 7.6 Surf 4W 12.0 Surf 5W 4.8 Surf 6W 6.5

FIGURES

Figure 1. Map showing the general location of the Prime Hook Lead Shot Site (drop zone).

Figure 2. Map of the Prime Hook Lead Shot Site showing the groundwater wells (DZ4- 6, UG1, and DG9) and surface water sampling sites (Surf 1 W through 8 W). A piezometer (PIEZ W) was installed and sampled at Surf 2W.

APPENDIX A

Plan for

Groundwater Water Monitoring at the

Prime Hook National Wildlife Refuge Led Shot Site, Milton, Delaware

Prepared by:

Fred Pinkney Sherry Krest

Environmental Contaminants Program 177 Admiral Cochrane Drive

Annapolis, MD 21401

Submitted to:

Mr. Bob Asreen

DNREC/SIRB

391 Lukens Drive New Castle, DE 19720

October 2006

Introduction

The operation of the Broadkiln Sportsman’s Club deposited lead shot on an adjacent portion of Prime Hook National Wildlife Refuge, Milton, Delaware. Cleanup activities involved the removal of lead contaminated soil to a concentration of 421 ppm (Guy et al.

2003). Groundwater monitoring, conducted by the U.S. Geological Survey (Soeder and Miller 2003), detected lead at concentrations as high as 1420 µg/L in a shallow unconfined aquifer. In addition to lead, antimony and arsenic were detected at elevated concentrations in groundwater and are also considered analytes of concern.

Long-term assessment of groundwater contamination is needed to determine the need for additional remediation. Ultimately, the objective is to ascertain whether the site can satisfy the requirements for a Closure Plan subject to approval by the State of Delaware, Department of Natural Resources and Environmental Control (DNREC), Division of Air and Waste Management.

Here we provide details for a groundwater monitoring plan that will meet the following objective:

Measure concentrations of the chemicals of concern in Refuge=s groundwater to evaluate trends and determine if there is a continued release of lead-shot related contaminants from the former gun club.

This proposal was requested by the Department of the Interior, Central Hazmat Fund (CHF) and is being coordinated with DNREC, Division of Air and Waste Management.

Facility Description

Methods

Well Locations

A total of five wells would be sampled. These would consist of a) Three additional shallow wells placed within the removal area (Shaw 2006); b) one existing background well (UG-1) as described by Soeder and Miller (2003), and one downgradient well (DG- 9; Soeder and Miller (2003).

The three new wells are designated as DZ-4, DZ-5, and DZ-6. They were constructed on March 14, 2006 by MIG Environmental, a subcontractor to Shaw Engineering, who is under contract with the U.S. Army Corps of Engineers Omaha District. Total well depth was 12.82 feet for DZ-4, 12.56 feet for DZ-5, and 12.60 feet for DZ-6 (Shaw 2006).

Latitude and longitudes are as follows:DZ-4: 38N49’25.7”, 75 17’6.9”; DZ-5:

38N49’25.5”, 75W17’7.7”, and DZ-6 38N49’26.7”, 75W17’6.5”. All three of these are within the soil removal area and close to the property line between the Broadkiln Sportsman’s Club and the Refuge.

The existing well, to be used to measure background concentrations is UG-1 (11.89 feet).

The existing well DG-9, will be used to measure contaminant concentrations downgradient of the three new wells.

Copies of the Boring Logs for both sets of wells are attached as Appendix A. Historical data is presented in Table 1.

Table 1. Historical groundwater sampling data at proposed wells (USGS data are as dissolved (0.45 μm filtered) samples with concentrations in μg/L.

Well Sampled by: Date As Pb Sb

UG-1 USGS 5/16/01 <0.2 1.91 <0.05

DG-9 USGS 5/25/01 0.2 112 2.78

DZ-4

DZ-5

DZ-6

Well Sampling Procedures

Groundwater sampling will be conducted according to Standard Operating Procedures prepared by the U.S. Environmental Protection Agency’s Emergency Response Team (SOP Number 2007, EPA 1995) and the U.S. Geological Survey’s National Field Manual for the Collection of Water Quality Data (USGS 1999). Procedures to be used at Prime Hook will be documented as CBFO Standard Operating Procedures and included in the annual reports.

As described in Section 4.2 of USGS (1999), wells will be purged by removing volumes of standing water until pH, temperature, and conductivity readings are stable. A Solinst peristaltic pump with silicone pump tubing and LDPE well tubing will be used and water level will be recorded with a Solinst brand Mini 101 Water Level Meter. Washing procedures for the water level meter before the first sampling and between sampling dates will include soaking in phosphate-free liquid laboratory detergent followed by a rinse with deionized water, soaking in 10% nitric acid, and a final rinse with deionized water. A well volume will be calculated first by subtracting the depth to water from the total depth of the well and multiplying the height by the area of a cross section of the well. To minimize contamination, tubing will be disposed after each sampling event.

Samples will be pumped directly into precleaned I-Chem polyethylene bottles supplied by the analytical laboratory. After the requisite volume of unfiltered water is collected, an in-line Millipore (Catalog number: GWSC04510) 0.45 µm polyethersulfone filter will be installed and an appropriate volume of filtered sample will be collected into a second polyethylene bottle. Both bottles will contain several ml of nitric acid for preservation.

Quality assurance will meet EPA Region III protocols and include the analysis of filter blanks, instrument blanks, field duplicates, and matrix spike duplicates. Samples will be stored in iced coolers, maintained in a refrigerator at 4 ºC, and shipped (on ice) as soon as possible to the analytical laboratory (Severn-Trent Laboratory (STL), Edison, NJ). All procedures and locations will be documented in a bound field notebook. Chain of custody will be maintained according to CBFO Standard Operating Procedure 102.

Analytical Procedures

Samples will be analyzed by Severn Trent Laboratories, Edison, NJ (STL-Edison) according to EPA SW846 Method 6010B which utilizes Inductively Coupled Plasma Spectroscopy. According to Bob Schulte (DNREC, Division of Air and Waste Management, 302-395-2600), STL-Edison is certified by the State of Delaware for groundwater analysis. Certification is also provided in the quote with instrument quantitation limits of 8.68 ppb for antimony, 4.70 ppb for arsenic, and 2.70 ppb for lead.

A copy of the STL quote is attached as Appendix B.

Investigation-Derived Waste

Purge water (approximately 2 gallons per well) from the sampling wells will be stored on-site in approved 5-gallon high density polyethylene pails with screw cap lids. Once the sampling results are received and reviewed with DNREC, the contents will be either disposed on-site (poured onto the ground) or transported to a hazardous waste landfill.

Chain of custody and documentation of disposal forms will be maintained and included with the report.

Reporting

The laboratory will provide a report of the findings within 15 days of sample receipt including standard quality assurance reporting. The hard copy test report will be a Level III test report with detailed Delaware HSCA – SOP style hard copy data deliverable.

CBFO will interpret the data from each two seasons of sampling and prepare an annual report. Comparisons between the three site wells and the two background wells will be conducted according to statistical methods provided by DNREC.

Schedule

Sampling would be conducted in the fall of 2006 and every 6 months thereafter for a total of 10 years (20 sampling periods). The laboratory data report will be forwarded to DNREC upon receipt.

References

Environmental Protection Agency (EPA). 1995. Groundwater well sampling. Standard Operating Procedure #2007, Environmental Response Team, Edison, NJ.

Guy, C.P., M. Huston, S. Krest, and D. Murphy. 2003. Ecological Risk Assessment for the Prime Hook Lead Pellet Site, Prime Hook National Wildlife Refuge, Milton, DE U.S.

Fish and Wildlife Service, Chesapeake Bay Field Office, Annapolis, MD. CBFO-C03-04.

Shaw Environmental Inc. 2006. Final report. Prime Hook National Wildlife Refuge monitoring well and protective casing installation. Broadkiln Sportsmans Club, Milton, Delaware. Contract No. DACA45-03-D-0022, Task Order No. 48, prepared for U.S.

Army Corps of Engineers, Omaha, Nebraska.

Soeder, D.J. and C.V. Miller. 2003. Ground-water contamination from lead shot at Prime Hook National Wildlife Refuge, Sussex County, Delaware. Water Resources Investigations Report 02-4282, U.S. Geological Survey, Baltimore, MD.

U.S. Geological Survey 1999. National field manual for the collection of water quality data. Chapter A-4, collection of water samples. USGS, Denver, July 19, 2006

Mr. Fred Pinkney U.S. Fish & Wildlife Sevice 177 Admiral Cochrane Drive Annapolis, MD 21401

Re: Quote 921629b - Delaware Project (Revised)

Dear Mr. Pinkney:

STL Edison is pleased to provide this laboratory service price quotation for the referenced project. Parameters that you have requested a price quotation for are given below:

No. of Parameter Samples Unit Price Total Price

Group Metals - Ground Water:

Total Antimony, Arsenic & Lead (6010B) 9 $66.00 $594.00 Dissolved Antimony, Arsenic & Lead (6010B) 9 $66.00 $594.00

Number of Samples includes, 5 Monitoring Wells, 1 Duplicate Sample, 1 Matrix Spike, 1 Matrix Spike Duplicate and 1 Field Blank for a total of nine samples per round.

Total Projected Cost/Per Event/Year 1 & 2: $1,188.00 Total Projected Cost/Per Event/Year 3 & 4: $1,247.40 Total Projected Cost/Per Event/Year 5 & 6: $1,309.77 Total Projected Cost/Per Event/Year 7 & 8: $1,375.26 Total Projected Cost/Per Event/Year 9 & 10: $1,444.02

Individual Metals – Surface Water:

Total Antimony 3 $33.00 $99.00 Total Arsenic 3 $33.00 $99.00 Total Lead 3 $33.00 $99.00 Dissolved Antimony 3 $33.00 $99.00 Dissolved Arsenic 3 $33.00 $99.00 Dissolved Lead 3 $33.00 $99.00

Limits:

Compounds

Practical Quantitation Limits (PQL’s) µg/l

Instrument Detection Limits (IDL’s) µg/l

Antimony 10.0 8.68 Arsenic 5.0 4.70 Lead 3.0 2.70

QA/QC Level of Documentation: The hard copy test report will be a Level III test report with detailed Delaware HSCA – SOP style hard copy…