History
Construction and maintenance activities have been ongoing at the Corps’ Bonneville Lock and Dam for over 70 years. Many of the early maintenance and waste management practices took place at the east end of Bradford Island in areas off limits to the public. These areas include a historic landfill, a sandblast area, a pistol target range, and an area where waste was disposed directly into the Columbia River.
Landfill
Until about 1982, the landfill on Bradford Island was used to dispose of project waste materials like oil and grease, paint and solvents, scrap metals, mercury vapor lamps, cables and sand blast grit. Some electrical transmission components like switchgear, insulators and possibly light ballasts were also placed in the landfill. Household waste came from a small community of homes used by construction workers and later project personnel until 1976.
The total landfill area is about one-half acre in size (about one-third of a football field in area), and is estimated to hold about 8,800 cubic yards of material, including soil used to fill and cover the landfill. It is on the northeastern portion of Bradford Island, and is not in a public area.
Sandblast Area
The sandblast building was used for sandblasting and painting from about 1958 to 1995. The area impacted by sandblast grit includes the sandblast area and the transformer release area. A burn pit located southeast of the sandblast building and a septic system, not currently in use, northwest of the building are additional potential sources of contamination within the sandblast area. In addition, an area of previously unknown contamination was discovered in the course of soil sampling.
Findings of a 2006 investigation conclude that the area contains an estimated 1500 cubic yards of contaminated material.
Pistol Range
A small area, approximately 95 cubic yards, on the south side of the island was used for small arms target practice through the 1970s. Lead concentrations have been detected.
In-water
Hydrographic and underwater dive surveys in late 2000 led to the discovery of light ballasts on the Bulb Slope area off Bradford Island, impacting an area estimated at 100 cubic yards. Mercury is present, but the sediment has not been greatly impacted.
The dive survey also revealed power transmission components containing significant levels of PCBs (polychlorinated biphenyls).
Corps Response
In the late 1980s and early 1990s, the Corps began efforts to bring Bonneville Lock and Dam into compliance with new hazardous waste regulations. The Corps during that time was also developing the Environmental Review Guide for Operations program. ERGO is a comprehensive self-evaluation and program management system for achieving, maintaining and monitoring compliance with environmental laws and regulations at Corps of Engineers projects and facilities.
- 1990: The ERGO program was given a pilot test.
- 1991: Portland District's ERGO program became operational.
- 1992: The first internal ERGO audit of the Bonneville project was held.
The Corps was still learning what was needed to bring the project into compliance with hazardous waste regulations. The landfill was listed as a “minor finding” because the ERGO team did not at that time have information about contaminated items in the landfill (such as mercury vapor lamps).
- 1995: Retired and current employees were interviewed about the landfill.
- 1996: Contaminants were confirmed in the landfill and letters were sent to the Environmental Protection Agency and the Oregon Department of Environmental Quality, notifying them of a CERCLA Release.
- 1997: The Corps signed a Voluntary Cleanup Agreement with the Oregon DEQ.
- 1998: The Corps conducted a landfill site investigation.
- 2000: An underwater dive survey discovered equipment containing PCBs.
- 2002: Divers removed in-water electrical equipment.
- 2002: Specialists conducted a preliminary assessment and inspection of the sandblast area.
- 2003: Divers collected samples of in-water sediments and clams.
- 2004: The Corps completed an ecological and human health risk assessment.
- 2005: The Corps completed a draft engineering evaluation and cost analysis for the landfill and in-water areas.
- 2006: Divers conducted additional fish sampling.
- 2007: The Corps removed 65 tons of sediment from an 0.83-acre area along the shoreline of Bradford Island. 2.2 million gallons of water and sediment were suctioned from the river bottom and filtered to remove contaminants. The resulting filtered water that was returned to the river was non-detectable for PCBs at five parts per trillion. The captured sediment that was taken to a licensed landfill was non-detectable for PCBs at 80 parts per billion. The sediment results seem to indicate that the average contamination level in the river was far lower than originally estimated.