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EPA’s Involvement at this Site

PNS consists of three dry docks, 6,500 linear feet of berthing, and 376 buildings and other structures. From 1945 to 1975, untreated acidic and alkaline wastes, waste battery acid and
lead sludge, wastewater and spent baths from an electroplating operation, and other wastes from various industrial shops were discharged into the Piscataqua River via industrial waste outfalls. From 1945 until about 1978, 25 acres of tidal flats between two of the islands were filled with wastes, including chromium-, lead-, and cadmium-plating sludge; asbestos insulation; volatile organic compounds (VOCs); waste paint and solvents; mercury-contaminated materials; sandblasting grit containing various metal wastes; and dredged sediments from the Piscataqua River.

In the late 1970s, dredged sediment samples collected near the industrial outfalls were found to be contaminated with elevated concentrations of metals, polychlorinated biphenyls (PCBs) and other contaminants. The Navy has indicated that the probable source of the sediment contamination is the industrial outfalls at PNS. Groundwater supplies drinking water to 10,000 people within four miles of the site. However, groundwater beneath the PNS (the island) is not hydraulically connected to the groundwater that supplies drinking water. The mainland on both sides of the river in the immediate vicinity is a thickly settled residential area with commercial and light industrial land use activities.

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What is the current site status?

The site’s long-term remedy includes capping of the DRMO Storage Yard, stabilizing the DRMO shoreline, removing underground storage tanks, and removing the mercury burial vaults. Work is currently underway at seven areas, or operable units (OUs), at the site. In addition, preliminary evaluations of several Screening Areas are determining whether a remedial investigation should be performed at these areas. Monitoring of the Off-Shore Areas (OU-4) sediments and biota is ongoing. All of the site’s remaining OUs are in the remedial investigation (RI)/feasibility study (FS) phase of work. In the Superfund process, a site’s RI identifies the nature and extent of a site’s contamination. The FS evaluates various remedies to address the contamination

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What's being done to protect human health and the environment?

The site is being addressed through federal actions. Capping of the DRMO Storage Yard, stabilizing the DRMO shoreline, removing underground storage tanks, and removing the mercury burial vaults has provided for the protection of public safety and the environment while investigations into the nature and extent of contamination at the site are completed.

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