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.
1992: The first internal ERGO audit of the Bonneville project was held.
1996: Contaminants were confirmed in the landfill and the Environmental Protection Agency and the Oregon Department of Environmental Quality notified of CERCLA release.
1998: The Corps conducted a landfill site investigation.
2000: An underwater dive survey discovered equipment containing PCBs, which was removed in 2002.
2003: Divers collected samples of in-water sediments and clams. Additional sampling was conducted in 2006.
2004: The Corps completed an ecological and human health risk assessment.
2005: The Corps did a draft engineering evaluation and cost analysis for landfill and in-water areas.
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 water returned to the river was non-detectable for PCBs at five parts per trillion. The captured sediment 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.
2011: The Corps collected sediment and clams in the area dredged in 2007 and additional fish to compare with the fish collected in 2006. Results published in 2012 showed the contaminant levels have not been reduced by the dredging.
2012: The Corps published the Remedial Investigation report that summarizes all work to date.
2014: Complete the Feasibility Study for the river.
2014: Complete the Risk Assessments for the upland areas.
This information was last updated Oct. 3, 2013.