News Release
| Release Number: | 01-142 |
| Dated: | 10/11/2001 |
| Contact: | Public Affairs Office, 503-808-4510 |
Portland, Ore.-The U.S. Army Corps of Engineers will resume environmental impact investigations next week in an historic landfill on Bradford Island at Bonneville Lock and Dam.
These investigations will be done by URS Corporation, Portland, Ore., under an existing $744,000 contract. The original work plan (Supplemental Site Inspection, 1999) was developed by the Corps in coordination with the Oregon Department of Environmental Quality (DEQ) and URS. Landfill work at the project on the Columbia River 40 miles east of Portland was put on hold last fall after the discovery of electrical components in the Columbia River, adjacent to the landfill site. Since last fall, attention had been focused on the in-water site where as recently as last June, sediment, water and tissue samples of various kinds were collected by divers for analysis.
"The in-water site was unexpected," stated Mark Dasso, Corps project manager. "When we identified electrical components in the water, we needed to quickly get a handle on what we were dealing with, so we committed all our available resources for in-water work. When the final report on the dive comes in we'll coordinate with federal and state agencies to decide what comes next as far as in-water work. In the meantime, we have work to do in the landfill."
The intended work in the landfill will supplement previous investigations by filling in data gaps and will conclude with a final Site Investigation Report by the spring of 2002. That report will include a human health risk assessment, an ecological risk assessment, an analysis of any specific contaminated areas found, and a remediation alternatives analysis. Remediation actions, if needed, would follow when the report is completed.
On-site work will include groundwater sampling from three new monitoring wells and five existing wells to help determine water quality and hydraulic conditions such as flow, gradient, seepage and permeability in and around the landfill. Also taken into account to make this analysis as accurate as possible will be amounts of rainfall, evaporation, vegetation use, surface runoff and groundwater recharge which will help determine whether water (ground or surface) follows a path to the Columbia River.
A survey measuring vibrations (seismic refraction) will be used to measure the differences between the landfill and surrounding bedrock. This work will provide information to accurately assess the boundaries (including depth) of the landfill, and will help URS place new groundwater monitoring wells correctly.
During the investigation some known contaminants will be removed and test pits will be dug in areas where there could be other contamination. Mercury vapor lamps discovered in the landfill will be excavated and properly disposed. Soil and water samples will be taken to confirm removal of all mercury contamination from those lamps. A backhoe will be used to search the northwestern and west end of the landfill for any evidence of buried electrical components. Any found will be removed and properly disposed. Soil and water samples will be taken to verify removal of any contaminants that originated from those components.
Additional soil samples will be taken to detect areas of specific contamination ("hot-spot analysis"). This is an Oregon DEQ requirement. Contaminants of concern are lead and mercury. Also, site investigations will begin in three smaller sites on Bradford Island. Soil samples will be taken from a former waste storage area, a former pistol range and an area that was once used for sandblasting operations to find any contamination in those areas or on adjacent grounds.
The Corps identified the landfill site, used to dispose of household and project waste materials from 1942 until about 1982, as an area of concern during routine internal inspections in the mid-90s. A primary concern was contaminant migration from the landfill into the sediments or water of the Columbia River. In 1996, following further internal investigations and confirmation of landfill contents, the Corps notified DEQ about the landfill and the Corps' intent to investigate potential contamination at the site. To assure the landfi ll investigation would comply with regulatory agency requirements, a Voluntary Cleanup Program (VCP) agreement was signed in 1998 between DEQ and the Corps. The VCP makes the two agencies partners in the investigation, and any necessary cleanup or remediation, of the Bradford Island landfill. The landfill is in a part of Bradford Island that is not open to the public. It is forested and managed as wildlife habitat.
That agreement extends to the in-water site adjacent to the landfill. Thus, in spring 2001, divers placed membranes (lipid sheets or polyethylene sheets) in the river to determine PCB levels in the water column, took sediment samples in and around three known debris mounds and downstream by drains from a sandblast area, and mapped debris mounds to estimate the quantity and types of materials present. Because living organisms feed on materials that could contain PCBs that accumulate in tissue, divers also gathered freshwater clams and crawfish for tissue analyses.
The final report on work done during that dive will be completed in late October.