Site 2 - Fire Training Area
Site Description: Site 2 is located on the eastern side of a 9-acre clearing in the south-central portion of the former NWIRP Calverton facility. Prior to a 2008 Removal Action, an 80-foot diameter concrete ring used for fire training and piping associated with an air sparging/soil vapor extraction (AS/SVE) remediation system were located in the southeast corner of the clearing. A 1,000-gallon steel aboveground storage tank (AST) was used to store fuel and was removed in 1996. In addition, a 6,000-gallon storage tank was also removed sometime before 1982. Currently the site consists of a lightly wooded field.
Site History: The Fire Training Area was used by Northrop Grumman (NGC) and Navy crash rescue crews as a training area since 1955, and possibly as early as 1952. According to a 1986 Initial Assessment Study (IAS), soil disturbances in the area were continuously evident in historical photographs. Before 1982, activities at the site consisted of clearing an area up to 100 feet or more in diameter and enclosing it with an earthen berm. A layer of water was then placed within the bermed area. Waste fuels, oils, and waste solvents were floated on the water, ignited, and then extinguished. The IAS reported that up to 450 gallons of waste solvent were mixed with up to 2,100 gallons of waste fuel per year for use in the training exercises. Aircraft sections were sometimes placed in the area to simulate actual crash conditions. After 1975, waste solvents were reportedly no longer mixed with the waste fuels and oils to be ignited. Fire fighting materials used in the training exercises included aqueous fire fighting foam, gaseous Halon 1301, water, and dry chemical extinguishers.
A partially buried 6,000-gallon storage tank, formerly located north of the Fire Training Area ring, was used for an unknown period of time prior to 1982 to store waste fuels and solvents at the site. The concrete ring was constructed after a spill to prevent further soil contamination by waste fuels. A 1,000-gallon aboveground storage tank (AST) with secondary containment was installed 1982 to replace the 6,000-gallon storage tank. The 6,000-gallon storage tank was likely removed in the early 1980s. The AST was removed in the mid-1990s.
In February 2010, munitions and explosives of concern (MEC) was encountered. The MEC was likely from a firing stop butt area, not associated with Site 2, where aircraft 20-mm cannon firing systems were tested at the former NWIRP.
Environmental Investigations/Interim Actions: To address spills at the site, a groundwater recovery well and oil-water separation system was installed in December 1987 groundwater and free product extraction continued until 1993. Passive free product recovery continued until 1996.
In 1992, a Site Investigation (SI) was conducted. The results of the sampling and analysis confirmed the presence of contaminated soil and groundwater at Site 2. The primary soil contaminants are chlorinated and non-chlorinated volatile organics, with lesser concentrations of semi-volatile organics and inorganics. Low concentrations of polychlorinated biphenyls (PCBs) and pesticides were also found. Additional investigation was recommended at this site to characterize the nature and extent of both soil and groundwater.
RCRA Facility Investigation (RFI) evaluations began in 1994 and were completed in 2001. Field investigations were conducted in 1994, 1995, and 1997. The purpose of the RI was to characterize the nature and extent of contamination and estimate potential risks to human health and the environment.
In 1995, a human health risk assessment (HHRA) was conducted for the RFI report. The risk assessment found that there might be an unacceptable cancer risk to current workers. PCBs’ in the surface soil resulted in the most significant potential cancer risk. However, this risk is within the USEPA target risk range of 1 E-04 to 1 E-06. Residential exposure to soil and groundwater was also evaluated. Carcinogenic and noncarcinogenic risks exceeded the target risk range for both media. The primary risk drivers include solvents, polyaromatic hydrocarbons (PAHs), PCBs, arsenic, and manganese.
In addition to the potential for unacceptable risks to human health, the contaminant concentrations of several soil and groundwater samples exceeded state guidance or regulatory requirements. Soil contaminants detected at concentrations higher than state guidance include chlorinated and nonchlorinated VOCs, PAHs, PCBs, and several metals. Most of the exceedances were located east of the fire training ring. Groundwater contaminants detected at concentrations higher than drinking water standards and groundwater quality standards included a variety of chlorinated and nonchlorinated solvents, dichlorobenzene, phenolics, PAHs, pesticides, PCBs, and metals.
In 1995, a pilot-scale study for an AS/SVE was constructed and operated seasonally through 2000. Approximately 46 pounds of target chlorinated volatile organic compounds (VOCs) and 8 pounds of target non-chlorinated VOCs were removed from soil. Approximately 30,000 pounds of organics (measured as carbon) were also destroyed through biodegradation.
In 2008 and 2009, a Removal Action was conducted to address shallow petroleum-contaminated soil (less than 6 feet below ground surface). Approximately 11,408 tons of petroleum-, solvent-, and PCB-contaminated soil and 1 ton of crushed buried drums were excavated, characterized, and disposed off site. In addition, approximately 1,100 pounds of calcium oxyhydroxide was applied to the excavated area to promote biodegradation of residual petroleum contamination.
From 2012 to 2015, MEC response actions commenced at Site 2. Activities included mechanical excavation to a minimum depth of 18 inches below ground surface (bgs), manual screening, and backfilling throughout the majority of the Site. Approximately 1.8 acres were surfaced cleared of MEC. Suspected MEC and material potentially presenting an explosive hazard (MPPEH) were encountered throughout the area and were classified as 20-mm projectiles or pieces of 20-mm projectiles. Approximately 19,200 projectiles or pieces of projectiles were recovered and removed. Weathered drums (and remnants of crushed drums) containing oil-like waste, Freon contaminated soil, paint-like waste, and tar were encountered and removed.
Beginning in 2016, poly- and perfluoroalkyl substances (PFAS) investigations were conducted on and off Navy property because AFFF was used during fire training activities. Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) were detected in groundwater above the USEPA drinking water Health Advisory (HA) of 70 nanogram per liter (ng/L). PFAS was also detected in surface and subsurface soil and surface water.
Current/Future Action: A Record of Decision (ROD) for an interim action to address MEC was finalized in 2018. A Remedial Action to address MEC is planned for Fall 2018 through Spring 2019. A ROD to address VOCs in groundwater is on hold while the investigation for PFAS continues at Site 2.
Aircraft Paint Hangars
Site Description: Building 168 – “New Aircraft Paint Hanger” and Building 318 – “Rehab Existing Paint Hanger” are located in the south-central portion of the facility and north west of ERP Site 6A – Former Fuel Calibration Area. During the 1997 Environmental Basewide Survey (EBS), these aircraft hangars were identified as containing fire suppression systems that utilized AFFF, which is a known source of PFAS. The Hangars were equipped with trough drains that were routed to rinse water tanks (Building 168) or to a sump where the water was pumped to an Industrial Waste Treatment Plant. Reportedly, all AFFF systems at Calverton were replaced with wet-systems by 1998 or buildings were demolished.
Site History: The AFFF system at the Aircraft Paint Hangars may have been tested in the 1980-1981 timeframe by a full dump of water and AFFF inside the structure, and the residual AFFF / water reportedly was not captured. The drainage system in this area most likely discharges to the Site 6A – Former Fuel Calibration Area swales.
Environmental Investigations/Interim Actions: Beginning in 2016, PFAS investigations were conducted using the existing monitoring well network at Site 6A – Former Fuel Calibration Area and Southern Area. PFOA and PFOS were detected in groundwater above the USEPA drinking water HA of 70 ng/L. PFAS was also detected in surface water.
Current/Future Action: The investigation for PFAS is ongoing at the Aircraft Paint Hangars.