Record of Decision System (RODS)
NAVAL AIR DEVELOPMENT CENTER (8 WASTE AREAS)
|Site Name:||NAVAL AIR DEVELOPMENT CENTER (8 WASTE AREAS)|
|Address:||ST & JACKSONVILLE ROAD|
|City & State:||WARMINSTER TOWNSHIP PA 18974|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
The Pennsylvania Department of Environmental Resources (PADER) recommended excavation and disposal of fire residuals and contaminated soils at Site 8 in October 1986. The Site was proposed for inclusion on the National Priorities List (NPL) also in 1986, and placed on the final NPL on October 4,1989. By October 1988, the double soil berms on Site 8 had been removed. Naval Air Warfare Center (NAWC) personnel reported that these berms, fire residuals, trapped liquids, and soil from eroded areas had been analyzed and removed. The berm material was deposited in an area adjacent to Site 8 and the area was regraded.
The Phase I Remedial Investigation (RI) was initiated in late 1988. The RI was completed and the Phase I RI Report was released on September 11, 1990. Phase I initiated the investigation of sites 1 through 8 by screening these sites for volatile organic compounds via soil gas analysis, electromagnetic surveys, soil borings, and by installing and sampling shallow monitoring wells.
On September 20, 1990, the Navy and EPA signed an Interagency Agreement (IAG) which established a procedural framework for developing and implementing investigative and response actions at the Site in accordance with CERCLA and the National Contingency Plan.
The Phase II RI was initiated in late 1991. This work included installing additional monitoring wells, analyzing groundwater, and evaluating aquifer characteristics. Four off-site wells were sampled during the Phase II RI. Based on the results on the investigations of Phases I and II, the Navy completed RI and Feasibility Study (FS) Reports addressing contaminated groundwater in OU-1 in April 1993.
In October 1993, a focused RI was initiated to further investigate the nature and extent of contaminated groundwater attributable to Areas A, B, and C, as well as in the vicinity of the main building complex at the base (Area D).
On September 29, 1993, the Navy Jointly signed a Record of Decision with the EPA for OU-1. The ROD for OU-1 selected an interim remedy which included the pumping and treatment of groundwater to limit the migration of contaminated groundwater attributable to Areas A and B.
From April 28, 1993 through September 30, 1994, the Navy sampled more than 500 wells to assess the impact of contaminated groundwater attributable to NAWC on off-site groundwater users in Areas A and B. Seven residential wells sampled exceeded EPA Removal Action Levels, while an additional thirty-nine residential wells exceeded Maximum Contaminant Levels (MCLs). At least part of this contamination is potentially attributable to the Site. In response, the Navy has conducted a CERCLA removal action, installing a water treatment system in each residence whether either EPA Removal Action Levels or MCLs have been exceeded.
The EPA determined this off-site groundwater contamination may present an imminent threat to human health. In response, the EPA and the Navy have conducted additional CERCLA removal action work which provided residences exceeding EPA Removal Action Levels, as well as residences in the immediate path of the groundwater contamination, with connections to public water supply systems. The work completed under this Removal Action is considered to be Operable Unit Two (OU-2).
In August 1994, The Navy released a Focused Feasibility Study (FFS) Report for OU-3 (contaminated groundwater attributable to Area C) at the Site. The FFS for OU-3 developed several remedial alternatives for addressing contaminated groundwater attributable to Area C. From June 1994 through December 1994, the EPA initiated and completed construction of the removal action for OU-2. In January 1995, the Navy initiated construction of the remedy for OU-1.
Alternative 2 includes placing and maintaining a two-foot vegetated soil cover over site wide subsurface soils to ensure that subsurface soils exceeding remediation levels are not available for human exposure. Site wide subsurface soils are defined as soils in areas where subsurface disposal has occurred. Engineering controls will be implemented as necessary to establish and maintain the soil cover. Initially, the site will be evaluated to determine where soil and/or vegetation must be placed and to identify any engineering controls necessary to establish/maintain a permanent soil cover. Soil/vegetation will be placed and engineering controls implemented as necessary based on
this evaluation. Once established, the two foot vegetated soil cover will be permanently maintained.
Institutional controls to ensure permanent maintenance of the soil cover and establish excavation controls shallconsist of deed restrictions. In particular, the deed prepared by the Navy for the transfer of the property shall provide that the vegetated soil cover present at the time of transfer shall remain in place and provide that any plans for excavation below two feet within the area of site wide subsurface soils must be approved by the Navy and/or EPA. Such approval shall consider the available information and be contingent on the submission and approval of a plan
which ensures that necessary measures are undertaken to protect human health and the environment. Periodic monitoring will be conducted to identify maintenance activities required for the vegetated soil cover shall be performed and any necessary actions taken to enforce deed restrictions.
Every five years, a review will be conducted to evaluate the site status and to determine whether further action is necessary. Periodic review will be required because the selected remedy allows contaminants to remain at concentrations which are not protective of unrestricted land use.
Estimated Capital Cost: $83,000
Estimated Annual O&M Costs: $8,000
Estimated Present Worth Costs: $225,429
Estimated 5-Year Review Costs: $20,000
Alternative 2 includes placing and maintaining a two-foot vegetated soil cover over site wide subsurface soils to
ensure that subsurface soils exceeding remediation levels are not available for human exposure.
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