Record of Decision System (RODS)
NEW LONDON SUBMARINE BASE
|Site Name:||NEW LONDON SUBMARINE BASE|
|Address:||ROUTE 12 CRYSTAL LAKE RD|
|City & State:||NEW LONDON CT 06349|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
|Contaminant:||Toluene, ethylbenzene, xylene, DDT, DDD, DDE, polycyclic aromatic hydrocarbons, heavy metals, beryllium, barium, cadmium, copper, nickel, zinc, chromium, lead|
Please note that the text in this document summarizes the Record of Decision for the purposes of facilitating searching and retrieving key text on the ROD. It is not the officially approved abstract drafted by the EPA Regional offices. Once EPA Headquarters receives the official abstract, this text will be replaced.
The United States Navy Submarine Base - New London (NSB-NLON) consists of approximately 547 acres of land and associated buildings in southeastern Connecticut in the towns of Ledyard and Groton. NSB-NLON is situated on the eas bank of the Thames River, approximately six miles north of Long Island Sound, an is bounded to the east by Route 12, to the south by Crystal Lake Road, and to th west by the Thames River. The northern border is a low ridge that trends approximately east-southeast from the river.
NSB-NLON currently provides a base command for naval submarine activities in the Atlantic Ocean. Additionally, NSB-NLON includes housing for Navy personnel and their families, submarine training facilities, military offices, medical facilities, and facilities designed for the maintenance, repair, and overhaul of submarines.
Land use adjacent to the NSB-NLON is generally residential or commercial. Residential developments border the NSB-NLON to the north and extend north into the Gales Ferry section of Ledyard. Property along Route 12 to the west of the NSB-NLON consists of widely spaced private homes and open, wooded land. Further south on Route 12, development is a mixture of commercial and residential properties that include automobile sales and repair facilities, convenience stores, restaurants, a church, and a gasoline station. Private residences and a automobile service station are located along the south side of the NSB-NLON alon Crystal Lake Road; further south is housing for Navy personnel.
The Groton Water Department supplies potable water to NSB-NLON. The primary sources of the Groton water supply are reservoirs that are supplemented with wells. The water supplies are located within the Poquonock River Watershed, which is not within the NSB-NLON watershed. Groundwater at NSB-NLON is not used for potable water.
The Area A Landfill is located in the northeastern and north-central section of NSB-NLON. The area is approximately 13 acres in size. The Area A Landfill was opened sometime prior to 1957. From 1963 to 1973, nonsalvageable materials generated by submarines and base operations were disposed in the Area A Landfill There are no records indicating the volume or type of waste disposal in the landfill. However, they may include radioactive wastes and medical wastes from the hospital; industrial wastes from ship repair and maintenance facilities; commercial/residential wastes from housing and office facilities; and bulky wastes from construction activities. On-site landfilling operations ceased in 1973, and a bituminous concrete pad was constructed in the southwest portion of the landfill for staging of industrial materials and equipment.
At the time of the Initial Assessment Study, 42 steel drums, 87 transformers (both mineral oil and PCB filled), and 60 to 80 electric switches were stored on the bituminous concrete pad. Two transformers and several electrical switches were leaking at that time. Past leakage of oil was also evident. Most drums were stacked on wooden pallets. Drums with PCB labels were covered and bound with plastic sheeting. All of these materials have been properly disposed of of site. There are no written records regarding storage of materials on the concrete pad. All available information regarding use of the pad is based on th survey and interviews with Subase personnel.
In recent years, sand bags and contractor supplies and equipment have been store over the former landfill. Several transformers, crane weights, excavated underground storage tanks, and other equipment were stored on the bituminous concrete pad in the southwest portion of the landfill. The specific items store in this area change over time. A gravel-covered, long-term vehicle parking lot also exists on the former landfill.
The sources of contamination detected at the Area A Landfill are predominantly the materials discarded at the landfill. Documented soil contaminants detected, based on investigations performed, include the following: volatile organic compounds (VOCs), predominantly toluene, ethylbenzene, and xylene; semivolatile organic compounds (SVOCs), including polycyclic aromatic hydrocarbons (PAHs); pesticides, predominantly DDT, DDD, DDE; polychlorinated biphenyls (PCBs); and inorganic constituents of concern (heavy metals), including beryllium, barium, cadmium, copper, nickel, zinc, chromium, and lead.
|Remedy:||This remedy is the first of two operable units for the site and addresses source control. Management and migration of contaminants in the groundwater will be addressed as a separate operable unit. The major components of the selected remedy include: capping of the site with a multi-layer cap; landfill gas control to manage landfill gas migration; surface controls to minimize erosion and manag runoff; use of fencing and institutional controls to control site access and future site use; provisions for conducting additional studies, including determining if additional measures, beyond capping, such as a leachate/groundwater collection system, must be taken to further contain contaminants and enhance stability; a leachate/groundwater collection system may be installed to further contain landfill wastes and stabilize the cap if pre-des|
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