B.08 GFI JB CHS PBR CS023 (SWMU 23) Draft Final Monitoring & LUC Inspection Work Plan.pdf

Attachment A. SWMU 23 (CS023) MONITORING AND LUC

INSPECTION WORK PLAN

Uniform Federal Policy

Quality Assurance Project Plan

Draft Final December 2020

Version 00

Basewide Groundwater, Surface Water, and Land Use Control Monitoring

Joint Base Charleston Weapons, Charleston, South Carolina

Contract FA8903-15-C-0016

Prepared for:

AFCEC/CZRE

US Air Force Civil Engineer Center 772nd ESS/PKS

2261 Hughes Avenue, Suite 155 JBSA Lackland, TX 78236-9853

Prepared by:

AECOM

4016 Salt Pointe Parkway

North Charleston, South Carolina 29405

With Teaming Partners:

UFP-QAPP Attachment A: SWMU 23 (CS023) Monitoring and LUC Inspection Work Plan Basewide Groundwater, Surface Water, Land Use Control Monitoring

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 1 BWJ140078

1.0 SITE INFORMATION

Site Description Site Name: Old South Annex Sanitary Landfill (Solid Waste Management Unit

[SWMU] 23/CS023)

Site Stage: Long-Term Management (LTM) Location Joint Base Charleston (JBC) Weapons is located 10 miles north of Charleston, South Carolina, approximately 16 miles inland from the Atlantic Ocean. The facility is situated in two counties, Berkeley and Charleston, and occupies 16,868 acres. SWMU 23 occupies approximately 10 acres in the South Annex, between Perimeter Road and Goose Creek, and is heavily vegetated by marsh grass, trees, and shrubs (Figure 1).

Historical Use The landfill was used for disposal of construction material and other debris generated at the South Annex from 1918 until sometime between 1942 and 1978. Conflicting information is available on the discontinuance of landfill use. Reported dates of cessation of the landfill are 1942 in the interim Resource Conservation and Recovery Act (RCRA) Facility Assessment (Kearney/Centaur, 1988);

prior to 1952 in the draft Confirmation Sampling Report (ABB Environmental Services, Inc. [ABB- ES], 1993); and 1978 in the Initial Assessment Study (Harmon Engineering and Testing, 1984).

In addition, an assessment conducted in 1977 of the Charleston Army Depot (currently the South Annex) indicated that the landfill was used on an as-needed basis (United States [US] Army, 1977). When the landfill was in operation, combustible materials were burned, and the remaining residue was covered with soil. Materials reportedly disposed included wood, packing and shipping debris, tires, and household refuse (Harmon Engineering and Testing, 1984; US Army, 1977).

The landfill also reportedly received sludge from the industrial wastewater treatment plant (Kearney/Centaur, 1988).

SWMU 23 is approximately 10 acres in size and has an unpaved access road that extends from Perimeter Road to the Goose Creek tidal marsh. The access road ends at the eastern edge of the SWMU at an L-shaped configuration of metal storage containers used by the Naval Information Warfare Systems Command (NAVWARSYSCOM) to support operation and maintenance of an adjacent antenna array. The NAVWARSYSCOM antennas are located at the ends of five piers that extend up to approximately 160 feet from the eastern border of the SWMU 23 site into the tidal marsh.

Previous Investigations Several investigations have been conducted at JBC Weapons (formerly Naval Weapons Station Charleston) that have included SWMU 23. An installation assessment of Charleston Army Depot (now referred to as the South Annex) was conducted to search for, identify, and assess actual or potential chemical, biological, or radiological contaminant migration at the Charleston Army Depot and to identify any immediate on-post safety problems (US Army, 1977). The assessment indicated that a sanitary landfill in the western portion of the marsh, bordering Perimeter Road (corresponding to the approximate location of SWMU 23), contained old building materials, packing and shipping debris, and tires. Combustible materials reportedly were burned, and the remainder of debris covered with soil. The landfill was operated on an as-needed basis. The assessment reported that no known contaminants had been placed in the landfill.

An Initial Assessment Study (IAS) for JBC Weapons was completed in January 1984 (Harmon Engineering and Testing, 1984). The IAS was prepared to identify and assess potential sites

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 2 BWJ140078 posing a threat to human health or the environment from contamination from past hazardous materials operations. Based on information from historical records, aerial photographs, field inspection, and personnel interviews, 18 potentially contaminated sites were identified at JBC Weapons and were evaluated in the IAS. Five of the 18 sites were recommended for further study (as part of a Confirmation Study) based on their potential threat. SWMU 23 (identified as Site 17 in the IAS) was not recommended for further study in the IAS because of the innocuous nature of the waste.

An Interim RCRA Facility Assessment (RFA) for JBC Weapons was conducted in 1988 (Kearney/Centaur, 1988) to update the IAS performed in 1984. The interim RFA was required because JBC Weapons began operating under a RCRA interim status. Twenty-five SWMUs and eight areas of concern were identified at JBC Weapons and evaluated in this report. Because of the uncertainty of what was landfilled at SWMU 23, the Interim RFA recommended further investigation at SWMU 23 to determine whether any hazardous waste constituents were present.

Sampling was conducted at SWMU 23 in 1993 as part of the Confirmatory Sampling at Corrective Action Management Plan (CAMP) Group B sites. A draft report was issued that was never finalized because additional field work was warranted. Based on the results of the confirmatory sampling, the Supplemental Confirmatory Sampling Work Plan for CAMP Group B was prepared (ABB-ES, 1997). An addendum to the work plan was issued in 1997; the work plan with addendum is referred to as the RCRA Facility Investigation (RFI) Work Plan for SWMUs 2, 21, and 23.

The RFI field work was performed in 1997 (TtNUS, 2000a). The RFI included soil, surface water and sediment sampling as well as installation of five groundwater wells and groundwater sample collection. Aquifer pumping tests were performed at each well.

A few sporadic detections of organic constituents were encountered in site soils. Inorganic constituents in soil were largely attributable to naturally occurring, with the exception of sodium which is likely the result of saltwater intrusion. Maximum concentrations of antimony, arsenic, cadmium and silver exceeded background groundwater concentrations and are potentially related to the landfill.

Elevated concentrations of inorganic constituents were present in site sediment and surface water. A few organic constituents were also present. There does not appear to be a correlation with the soil/groundwater data. Unfortunately, background surface water and sediment data are not available to assess whether the contaminant concentrations detected in the surface water and sediment data are site related. For all media sampled, there was no one contaminant standing out as being site related.

No significant potential human health risks are associated with exposure to surface soil, surface water, and sediment at SWMU 23 under current and future potential land use. Direct contact with subsurface soil and groundwater is not anticipated. A majority of the inorganic constituents detected in the site soil (surface and subsurface) samples are present at concentrations indicative of naturally occurring constituents.

No potential ecological risks are associated with surface soil or groundwater. Only tin in groundwater is of potential concern but it is unlikely that tin is present entirely as tributyl-tin, the most toxic form. Inorganic constituents in sediments appear to pose low to moderate potential ecological risks to benthos and semi-aquatic receptors.

It was concluded that there are limited groundwater impacts into the surrounding marsh from SWMU 23. A direct exposure route between groundwater and potential surface receptors was not established. The groundwater is saline and is not expected to be used as a potable water source.

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 3 BWJ140078

The RFI was considered incomplete and additional samples were collected in October 1999 and documented in the Supplemental RFI (TtNUS, 2000b). The Supplemental RFI included an additional nine surface water and sediment samples from the tidally influenced Goose Creek marsh. Surface water and sediment samples were co-located. Each of the existing monitoring wells was also sampled.

The Supplemental RFI summarized all data collected to date at SWMU 23. The results of this evaluation indicate that the majority of metals detected at SWMU 23 are near or below the background concentrations for each of the media sampled with the exceptions being less than double the background concentrations. There was a general decrease in metals concentrations detected at SWMU 23 compared to previous investigations.

Surface water and sediment samples were collected to determine the full extent of ecological impacts from SWMU 23. Results from the additional sample collection indicated a limited impact on the marsh from contaminants originating from SWMU 23 and an order of magnitude decrease in metals concentrations in the marsh relative to previous investigations. With the exception of copper, concentrations of metals detected in sediment samples during the Supplemental RFI were less than historical and background concentrations (upgradient samples established as background in RFI). Based on the results of the Supplemental RFI and previous investigations, the impact to the marsh from SWMU 23 is negligible.

Following the 2000 Supplementary RFI, periodic monitoring was performed through 2012. The first year of monitoring (2002) included quarterly sample collection documented in an annual report. Two additional wells (23MW06 and 23MW07) were installed in 2002 prior to the start of quarterly monitoring. Arsenic was identified as the analyte of most concern in groundwater. Based on discussions during the March 2004 partnering meeting, the analyte list was modified to include pesticides/polychlorinated biphenyls, and well 23MW01 was eliminated from future monitoring (TtNUS, 2004).

In 2007, the fifth year of annual monitoring was performed (Terraine, 2007). Groundwater sampling was conducted quarterly for the first two years of the monitoring program. During the third, fourth, and fifth years of LTM, groundwater samples were collected semi-annually. Based on Year 5 analytical results, arsenic was considered the analyte of most concern. Arsenic was detected in three wells (23MW03, 23MW05, and 23MW07) at concentrations exceeding the maximum contaminant level (MCL). Based on review of five years of quarterly and semi-annual monitoring, it was determined that no seasonal trends were observed. Annual monitoring was recommended. The analyte list continued to include polychlorinated biphenyls (PCBs) which were to be collected at alternating locations (23MW04 and 23MW07) on the downgradient side of the landfill.

In the 2012 monitoring report (TEC-BSC, 2014), arsenic and cobalt were established as the constituents of potential concern (COPCs) in groundwater. Pesticides and PCBs were analyzed at two downgradient locations (23MW04 and 23MW07). Annual monitoring and a revision of the Basewide background study to define the background metals concentrations in the various hydrologic environments at the facility were recommended, along with continued monitoring for total and dissolved metals to evaluate metals mobility in groundwater.

A facility-wide conceptual site model (CSM) was prepared (AECOM, 2014) which included a tidal study at SWMU 23. It was determined that there is no observable response to tidal changes in water levels at the site.

The RFI Addendum (AECOM, 2018a) documents the completion of additional investigation efforts to define the previously identified groundwater plumes for arsenic and cobalt. The South Carolina Department of Health and Environmental Control (SCDHEC) requested additional investigation

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 4 BWJ140078 to delineate arsenic and cobalt in groundwater along the southern boundary of the site, since arsenic and cobalt were identified as COPCs in groundwater. In August 2016, a total of three monitoring wells (23MW08, 23MW09, and 23MW10) were installed at SWMU 23 to delineate the horizontal extent of COPCs in groundwater. The three new monitoring wells are located at the edge of the landfill surface (adjacent to the marsh) and define the horizontal extent of the groundwater plume. Well 23MW10 does not have elevated concentrations of either arsenic or cobalt in groundwater and defines the extent of the plume to the northeast. Wells 23MW08 and 23MW09 define the plume extent to the south and southeast at the landfill boundary (adjacent to the marsh). SCDHEC approved the RFI Addendum in their letter dated June 20, 2018, confirming that RFI activities are completed at SWMU 23.

Interim Measure (IM) injections were performed at temporary injection points (IPs) in the vicinity of 23MW05, 23MW08, 23MW09, and 23MW10 in March 2017 as documented in the IM Completion Report (AECOM, 2018b). The objective of the IM was to evaluate the applicability of PeroxyChem EHC Metals (EHC-M®) as an amendment to remediate low levels of metals in groundwater along the downgradient side of the landfill. Post-injection groundwater monitoring was performed in June, September, and December 2017 and March 2018. Post-injection monitoring results are presented in the IM Completion Report (AECOM, 2018b).

Changes in groundwater geochemistry were observed following injections. Oxidation reduction potential (ORP) levels decreased but either did not decrease to sufficient levels and/or levels did not remain at low levels to sustain the conditions necessary to decrease metals concentrations.

An increase in pH was also observed, which is expected as oxidation of zero valent iron (ZVI) releases hydroxide ions, which create basic conditions.

Contaminant concentrations fluctuated following injections with initial increases of arsenic in wells 23MW07, 23MW08, and 23MW09. Arsenic is more soluble under reducing conditions and therefore more mobile, which may account for the initial increases of this COPC. Cobalt concentrations decreased to below project action limits (PALs) at all wells except 23MW05;

however, a consistent response has not been observed at all wells located within the injection area. Annual monitoring has been conducted at SWMU 23 in each year since the IM was implemented. Surface water monitoring began in 2018. Contaminants present in groundwater along the downgradient side of the landfill were not present in surface water at levels above their respective PALs.

Land Use Controls Land use controls (LUCs) have been implemented at the site to restrict human contact with solid waste material contained within the landfill, restrict soil disturbance activities that may expose waste material, and prohibit residential development of the site. These LUCs have been reviewed and approved by SCDHEC and will be maintained during remedial action. Additional LUCs include providing signage identifying the landfill; prohibiting groundwater use for potable purposes; and adding administrative controls as part of a facility-wide notification system that alerts individuals who want to perform activities (i.e., well installation, construction, etc.) in the vicinity of SWMU 23 that LUCs are in place. LUCs at JBC Weapons are tracked through inclusion of the site in the JBC Weapons Installation Development Plan. The Base Remedial Project Manager works with the 628 Civil Engineer Squadron Base Community Planner (Base Community Planner) to confirm that LUCs are implemented and enforced at applicable sites. Annual LUC inspections will be performed to confirm compliance with the LUCs using the SWMU 23 LUC Monitoring Checklist (Attachment 1).

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 5 BWJ140078

2.0 SUMMARY OF PROJECT TASKS

Groundwater monitoring, surface water monitoring, LUC inspections, contingency injections, and annual reporting are included in the remedy for SWMU 23 in accordance with the Statement of Basis. Groundwater monitoring will be conducted for metals (total and dissolved), volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), PCBs, cyanide, and pesticides at ten monitoring wells. Surface water sampling will be conducted for arsenic and cobalt at three surface water points considered to be points of compliance for groundwater contaminants.

The LUC inspection program is being implemented in accordance with Appendix D of the RCRA Permit (SC8170022620). Annual inspections will be conducted to ensure that the LUCs remain in effect at the site. The area to be covered by the LUCs is presented on Figure 1. The LUCs ensure that proper planning, permissions, and safety considerations will be implemented prior to future construction activities or change in land use on the site. In support of this, the following field activities/schedule will be conducted:

Task Frequency Anticipated Month

Information Reported to Regulators

Documentation of LUC boundaries in the Installation Development Plan and review of proposed activities within the LUC boundaries through the Base dig permit process.

Ongoing Ongoing Report change in land use, if any.

Groundwater Monitoring Annual Fourth Quarter Within 90 days of sampling Compliance Point (Surface Water) Monitoring Annual Fourth Quarter Within 90 days of sampling

LUC Inspections Annual Fourth Quarter Within 90 days of inspection

2.1 Groundwater Monitoring

Groundwater monitoring will be conducted annually during the fourth quarter of the year. Prior to each sampling event, groundwater levels will be collected from each of the nine wells. Water level measurements will be made to the nearest 0.01-foot using an electric water level meter.

Groundwater samples will be collected using low-flow sampling techniques. Measurement and sampling procedures will be conducted in accordance with the Standard Operating Procedures (SOPs, Worksheet #21) and as described in Worksheet #14 of the Uniform Federal Policy – Quality Assurance Project Plan (UFP-QAPP).

A field duplicate sample and matrix spike/matrix spike duplicate (MS/MSD) will be collected during each sampling event. Table 1 summarizes the analytical methods by well.

2.2 Compliance Point (Surface Water) Monitoring

Surface water monitoring will be conducted annually during the fourth quarter of the year. These locations will be used as compliance points for arsenic and cobalt. Sampling procedures will be conducted in accordance with the SOPs (Worksheet #21) and as described in Worksheet #14 of the UFP-QAPP. Table 1 summarizes the analytical methods for each point.

Should analytical results at any of the surface water compliance points exceed the groundwater MCL during the annual sampling event, the compliance points will be resampled during the first quarter of the following year for both total and dissolved arsenic and cobalt to confirm the result.

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 6 BWJ140078

If the confirmation sampling is also above the MCL, the compliance points will be resampled during the second quarter of the year. If the results of the initial sampling, confirmation sampling, and 2nd confirmation sampling all exceed the MCL, implementation of the contingency remedy of in-situ chemical reduction will be discussed with SCDHEC. Based on the evaluation of analytical data and input from SCDHEC, an implementation plan will be developed and submitted to SCDHEC for approval prior to implementation.

2.3 Land Use Control Inspections

LUC inspections will be conducted annually. The inspections will consist of a site walk to observe site conditions, changes and repairs to existing soil cover, and any changes in site use that are inconsistent with LUC requirements. The LUC inspections will be documented using the LUC checklist (Attachment 1).

2.4 Annual Reporting

The groundwater monitoring results and completed LUC checklist will be submitted annually within 90 days of the monitoring activities. The annual report will document the groundwater and surface water monitoring activities, the analytical results, and LUC inspections along with any deficiencies and measures taken to correct deficiencies.

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 7 BWJ140078

Figure 1. SWMU 23 (LF023) Site Map

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 8 BWJ140078

REFERENCES

ABB-ES, 1993. Draft Confirmatory Sampling Report, CAMP Group B, Naval Weapons Station, Charleston, South Carolina. November.

ABB-ES, 1997. Supplemental Confirmatory Sampling Workplan, CAMP Group B, Naval Weapons Station, Charleston, South Carolina. January.

AECOM, 2014. Conceptual Site Model, Joint Base Charleston Weapons. March.

AECOM 2018a. Final RCRA Facility Investigation Addendum, SWMU 23, Joint Base Charleston

Weapons. May.

AECOM 2018b. Draft Interim Measures Completion Report, SWMU 23, Joint Base Charleston

Weapons. May.

Harmon Engineering and Testing, 1984. Initial Assessment Study of Naval Weapons Station

Charleston, South Carolina. NEESA 13-040. January.

Kearney/Centaur, 1988. Interim RCRA Facility Assessment Report, Naval Weapons Station, Charleston, South Carolina. Kearney/Centaur, a division of A.T. Kearney, Inc., Alexandria, VA. May.

South Carolina Department of Health and Environmental Control. Bureau of Land and Waste Management. Revised, 2015. Resource Conservation and Recovery Act (RCRA) Part B permit number SC8 170 022 620, effective 22 September 2011 through 22 September 2021.

TEC-BSC Joint Venture, 2014. Final 2012 Annual Monitoring Report, SWMU 3 – Old North Side Landfill, Naval Weapons Station Charleston, Charleston, SC. March.

Terraine Environmental Consulting, 2007. Year 5 Groundwater Monitoring Annual Report, SWMU 23, Old South Annex Sanitary Landfill, Naval Weapons Station, Charleston. April.

Tetra Tech NUS, Inc., 2004. Year 1 Groundwater Monitoring Annual Report for SWMU 23 – Old South Annex Sanitary Landfill, Naval Weapons Station Charleston, Charleston, SC. May.

Tetra Tech NUS, Inc., 2000a. RCRA Facilities Investigation Report for SWMU 23, Old South Annex Sanitary Landfill. Naval Weapons Station Charleston, Charleston, SC. June.

Tetra Tech NUS, Inc., 2000b. Addendum Supplementary Field Investigation RCRA Facilities Investigation Report for SWMU 23, Old South Annex Sanitary Landfill. Naval Weapons Station Charleston, Charleston, SC. June.

United States Army, 1977. Installation Assessment of Charleston Army Depot. Report No. 112, US Army Toxic and Hazardous Materials Agency. June.

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 BWJ140078

Table

Table 1 Groundwater and Surface Water Monitoring Matrix

SWMU 23

Location Sample ID Matrix Depth Metals - As, Co (total)

Metals (total)

Metals (dissolved)

VOCs SVOCs PCBs Cyanide Pesticides

6020A 6020A 6020A 8260B 8270D 8082A 9012B 8081B Annual Monitoring

23MW-02 23MW-02-YYYYMMDD Groundwater Shallow X X X X X 23MW-03 23MW-03-YYYYMMDD Groundwater Shallow X X X X X 23MW-04 23MW-04-YYYYMMDD Groundwater Shallow X X X X X 23MW-05 23MW-05-YYYYMMDD Groundwater Shallow X X X X X 23MW-06 23MW-06-YYYYMMDD Groundwater Shallow X X X X X 23MW-07 23MW-07-YYYYMMDD Groundwater Shallow X X X X X 23MW-08 23MW-08-YYYYMMDD Groundwater Shallow X X X X X X X 23MW-09 23MW-09-YYYYMMDD Groundwater Shallow X X X X X X X 23MW-10 23MW-10-YYYYMMDD Groundwater Shallow X X X X X 23SW17 23SW17-YYYYMMDD Surface Water X 23SW18 23SW18-YYYYMMDD Surface Water X 23SW19 23SW19-YYYYMMDD Surface Water X

Notes:

As - arsenic Co - Cobalt PCB - polychlorinated biphenyls SVOC - semi-volatile organic compound VOC - volatile organic compound YYYYMMDD - year, month, day

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 BWJ140078

Attachment 1: LUC Checklist