PORTLAND DISTRICT

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Bradford Island

Bradford Island is the island in the Columbia River at Bonneville Dam between the spillway and the first powerhouse.

Until about 1982, a small 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 sandblast grit. Some electrical transmission components like switchgear, insulators and possibly light ballasts were also in the landfill. Some 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 a 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. Other nearby potentially impacted areas on Bradford Island are included in this project.

The sandblast building material was used for sandblasting and painting from about 1958 to 1995. The area impacted by sandblast grit includes the sandblast area and an area where transformer oil was released onto the ground in 1995. A burn pit to the southeast of the sandblast building and a septic system northwest of the building (not currently in use) are more potential sources of contamination within the sandblast area. In addition, an area of previously unknown contamination was found in the course of soil sampling. An investigation in 2006 concluded there is an estimated 1500 cubic yards of contaminated material in the area.

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.

The Corps began investigating the potential for contamination from these activities in 1998. In 2000, when electrical equipment was discovered submerged in the river adjacent to the landfill, the study was expanded to include the north shore of Bradford Island and potential impacts from that equipment. In 2002 we removed the electrical equipment from the river bottom and in 2007 dredged sediment from approximately one acre of river bottom to remove PCB contamination from the environment.

About this project

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Recent Bradford Island activity

Portland District released the final Remedial Investigation Report in 2012 that documents our investigation of upland and in-river contamination, identifies the sources, nature and extent of the remaining environmental contamination and identifies potential concerns to human health and the environment.

The report concludes that contaminants both on land and in the water exceed risk screening levels and proposes that we perform a feasibility study of the in-water area to identify remedial actions that will lower concentrations to an acceptable risk level. It also proposes that we perform either a feasibility study of the land areas or a site-specific baseline Human Health Risk Assessment or Level III Ecological Risk Assessment to determine if risks to human health or ecological receptors are unacceptable.

We are proceeding with the Feasibility Study for the in-river area and expanded risk assessments for the upland areas.

In 2012 we published results of samples collected in the river in 2011 of sediment, clam and fish tissue. The report was produced to determine whether contaminant levels had changed at the in-river area since the dredging project in 2007. The results showed that contaminant levels have not been reduced by the dredging project and the Feasibility Study is the appropriate next step.

Status and timeline

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.

Release mechanisms and transport media

Volatilization of contaminants in soil to air, or dust generation and release of contaminants in particulate form to air.
Leaching and infiltration of contaminants from buried debris and/or contaminated soil to groundwater.
Discharge of contaminants in the perched groundwater zone to surface water (via seeps.)
Overland runoff of contaminants in soil directly to surface water or via the stormwater drainage system outfalls.
Transport of contaminants via soil erosion to surface water.
Sorption/dissolution of surface water contaminants to/from sediments.
Contaminated sediment transported within the river.
Potential surface water communication to the deeper groundwater zone.

Public impacts

The Oregon Health Authority and the Washington Health Department released health advisories. The Corps continues to work with state and tribal health agencies to inform area anglers about the danger of eating contaminated fish.