ARROWHEAD ASSOCIATES, INC./SCOVILL CORP.
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The Arrowhead Associates/Scovill Corp. Site is located approximately two miles southeast of the Town of Montross, Westmoreland County, Virginia. It is situated within Virginia’s Northern Neck region between the Rappahannock and Potomac Rivers. The Site occupies approximately 30 acres of land on the east side of State Route 3. The western portion of the Site consists of a one-story manufacturing building and a parking lot. The eastern portion of the Site contained five former sludge settling ponds and a treated wastewater pond.
Two former sewage water treatment ponds were located near the eastern edge of the property, which were used to treat sanitary wastewater generated by the facility. In addition, one chlorinated solvent tank and one acid tank are located along the northern edge of the facility. Both tanks are above-ground storage tanks and are presently empty.
An EPA removal action successfully reduced the risks presented by contaminated soils, on-site residual process wastes, and contaminated containers and manufacturing equipment at the Site. Nevertheless, significant residual contamination of isolated soil and underlying groundwater remained. Given the extent of contamination at the Site, EPA proposed it for inclusion on the National Priorities List (NPL) in June 1988. The NPL is a list of the nation most hazardous waste Sites. Once listed on the NPL, a Site can receive federal funding for a cleanup. The Site was added to the NPL in February 1990.
What Is Being Done to Clean Up the Site?
The Record of Decision (ROD) for the Site was signed on September 30, 1991. The remedy included a soil vapor extraction system (SVE) to remove volatile organics from contaminated soil in the Large Drum Storage Area (DSA) and the Chlorinated Solvent Tank Area (STA) both of which comprise Operable Unit 1 (OU1), and a pump and treat system to treat contaminated groundwater (Operable Unit 2, or OU2).
EPA issued an Explanation of Significant Differences (ESD) in 1998, approving the use of the permeable reactive subsurface barrier (PRSB) system in lieu of a pump and treat system at the Site in September 1998. PRSB System transforms dissolved volatile organic compounds (VOCs) into non-toxic products to attain remediation concentration goals in groundwater before groundwater discharges into surface water including the tributaries of the Scates Branch.
In September 2001, EPA amended the ROD to add a surface cap to the groundwater component of the selected remedy. The Surface Cap System was added to limit surface water infiltration into the subsurface immediately up-gradient of the PRSB.
The Site achieved Construction Completion with the signing of the Preliminary Close Out Report on September 27, 2002.
The third Five Year Review was completed in 2016.
What Is the Current Site Status?
The 2016 Five Year Review has found that the remedial actions at the Arrowhead Plating Superfund Site are not protective of human health and the environment.
- The SVE system has had limited success in removing the volatile organics from the contaminated subsurface soils to the required cleanup levels in the DSA, but was successful in treating STA subsurface soils (OU1). The removal of the VOCs from the DSA soils is necessary in order to attain cleanup goals in groundwater.
- The PRSB/Cap system to address contaminated groundwater, is not progressing as expected. The observation of VOCs downgradient of the PRSB, at concentrations several orders of magnitude greater than MCLs, indicates that contaminants are passing through or around the PRSB. The detection of TCE and 1,4-dioxane in groundwater seeps and surface water samples, particularly location SW1, collected as part of the quarterly monitoring investigations in 2011 and 2012 demonstrates that the remedy is not limiting contaminant migration. Additionally, the potential presence of perfluorooctane sulfonate (PFOS) and perflurooctanoic acid (PFOA) in groundwater, and the inability of the PRSB to treat 1,4-dioxane indicates the remedy is no longer appropriate for site conditions.
- The continued presence of TCE in indoor air is indicative of a source of contamination below the building. Based on recent data it appears likely that DNAPL is present under the building. This potential source area was not contemplated by the existing remedy and therefore does not address this area.
- Institutional Controls have also not been implemented at the Site. EPA is working with the current property owner to implement ICs.
EPA is preparing a Focused Feasibility Study to evaluate alternatives to address contamination in groundwater, including elevated levels beneath the building which have been demonstrated to be the cause for the vapor intrusion. The Screening of Alternatives document is currently undergoing review by EPA and the Virginia Department of Environmental Quality (VADEQ). The draft Focused Feasibility Study is being prepared and will be finalized in 2018. The revised remedy will also address groundwater not being treated by the PRSB. EPA is currently overseeing the effectiveness of vapor intrusion (VI) mitigation systems in the building.