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NPL Site Narrative for Hamilton Island Landfill (USA/COE)

North Bonneville, Washington

Federal Register Notice:  October 14, 1992

Conditions at Proposal (July 29, 1991): The Hamilton Island Landfill is in Skamania County in southwest Washington along the banks of the Columbia River adjacent to the Town of North Bonneville. A former river slough was filled in during the mid-1970s so that what was once an island is now part of the mainland. The site is owned and managed by the U.S. Army Corps of Engineers (USA/COE).

The 240-acre unlined landfill was used to dispose of material excavated during construction of a powerhouse for the Bonneville dam 1 mile upstream, as well as debris from the demolition of a nearby town. Approximately 19 million cubic yards of waste were disposed of at the site from 1977 to 1982, according to COE; paints, degreasers, and other chemical wastes were apparently also disposed of, presumably by COE contractors contrary to the terms of their contract.

A site inspection conducted by COE during 1987-89 found elevated levels of arsenic, cadmium, and various volatile and semivolatile compounds in surface soil, subsurface soil, ground water, leachate, and other discharges to the Columbia River. Discharges to the river from a culvert contained levels of copper above EPA's fresh water Ambient Water Quality Criteria established under the Clean Water Act. A wildlife mitigation area that receives site run-off contained elevated levels of toluene and zinc. COE fenced a portion of the site in 1987 to restrict public access.

Approximately 900 people obtain drinking water from wells within 4 miles of the site. The Columbia River, which eventually receives all run-off from the site, is a major recreation area used for fishing, boating, site-seeing, and wind-surfing. The Columbia River contains highly productive recreational and commercial fisheries adjacent to and downstream from the site. The site is within a Federally-designated National Scenic Area.

Status (October 1992): COE, EPA, and the Washington Department of Ecology will negotiate a Federal Facilities agreement under CERCLA Section 120 requiring COE to conduct a Remedial Investigation/Feasibility Study to determine the type and extent of contamination at the site and identify alternatives for remedial action.

For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet at ATSDR - ToxFAQs (http://www.atsdr.cdc.gov/toxfaqs/index.asp) or by telephone at 1-888-42-ATSDR or 1-888-422-8737.

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