Bass in Columbia Highly Contaminated, Tests Findby Michael Milstein
The Oregonian, March 17, 2008
New tests of smallmouth bass from the Columbia River near Bonneville Dam found fish with concentrations of industrial chemicals up to 26,000 times higher than what state officials consider safe for human consumption.
Officials warned against consuming fish from the area.
The fish were collected in 2006 near Bradford Island, an area where Bonneville Dam workers historically disposed of electrical equipment by dumping it in the river. Some of the equipment contained polychlorinated biphenyls, or PCBs, which is known to have contaminated the area.
The U.S. Army Corps of Engineers collected the 19 smallmouth bass in 2006 before using diver-operated suction hoses to vacuum some of the most contaminated sections of the river bottom. Testing of the fish found concentrations of PCBs ranging from a low of 32 parts per billion to a high of 26,000 parts per billion, with an overall average for all the fish of 3,000 parts per billion.
Click here to read the test results, and a second group of results.
The levels are much higher than the concentration of 1 part per billion that the Oregon Department of Environmental Quality considers safe for human consumption by someone eating large amounts of the fish over many years.
Officials tested the bass because they are generally considered resident fish and would be among the species most likely to be exposed to the contamination, said Scott Clemans of the Corps of Engineers. Salmon and other species that migrate through the area should not be at risk from PCB contamination, officials said.
Clemans said it's not clear that the source of contamination in the bass was the scrapped electrical equipment in the Bradford Island area, because the concentrations of PCBs in the fish did not seem to correspond to the age, size and location where the fish were collected.
Agencies are also testing clams, crayfish, sculpins, sediment and water from the area, but those tests are not complete yet.
The state Office of Environmental Public Health is reviewing the test results prior to issuing public fish consumption warnings for the Bradford Island area. Until then, anglers and consumers should refer to an advisory for the Portland Harbor, where similar levels of PCBs have been found in fish.
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