Salmon Show Alarming Levels of Illegal Chemicalsby Associated Press
Seattle Times - September 1, 2001
PORTLAND — Northwest salmon are testing positive for high levels of toxicants that were banned years ago, and federal experts don't know where the chemicals are coming from.
The National Marine Fisheries Service discovered industrial compounds called polychlorinated biphenyls, or PCBs, and the pesticide DDT in juvenile salmon over a testing period of three years.
Some of the chemicals, which were banned in the 1970s, are at concentrations high enough to damage fish immune systems, scientists said.
"We need to be cautious," said Tracy Collier, manager of the ecotoxicology program at the fisheries service. "We're close to the threshold where effects may begin to occur."
Experts are concerned salmon may pass the compounds along to predators that feed on them, such as cormorants, bald eagles and Caspian terns. All have tested positive for high levels of the compounds.
They aren't sure if the chemicals could harm humans who eat the adult fish.
The contamination could come from anywhere in the Columbia River system, including areas of past and present industrial pollution and farm and urban runoff, or from hatchery fish feed.
"They're going to have to look harder at the origin of those fish in order to answer those questions," said Larry Curtis, head of Oregon State University's Department of Environmental and Molecular Toxicology.
The National Marine Fisheries Service presented the findings in June to an independent panel of scientists mediating an impasse between the fisheries service and the Army Corps of Engineers. The two agencies are trying to agree about the environmental effects of a proposed dredging of the Columbia River navigation channel.
Scientists say they doubt the findings will stop the project. Fisheries-service officials, who must approve the deepening, are still negotiating with the corps about monitoring contaminant levels should the project go forward.
The National Marine Fisheries Service, charged under the Endangered Species Act with protecting threatened salmon, began systematically testing hatchery and wild juveniles for contaminants in 1998.
Tissue tests found PCB levels of 5 to 70 parts per billion. Salmon begin to show health impacts with PCB levels of 24 to 72 parts per billion, the fisheries service says.
The highest concentrations — more than 50 parts per billion — were found in fish from the Duwamish Estuary near Seattle; around Sand Island near the mouth of the Columbia River; in Yaquina Bay in Newport; and in the Salmon River, Alsea, Butte Falls and Cole M River hatcheries in Oregon.
DDT levels above 40 parts per billion were found in juvenile salmon from the Salmon River Fish Hatchery in Otis and around Sand Island in the Columbia River.
PCB and DDT-byproduct levels in bald eagles and cormorants are high enough to cause reproduction problems, said Jeremy Buck, environmental-contaminant specialist with the U.S. Fish and Wildlife Service.
Studies show bald eagles nesting along the first 60 miles of the Columbia River produce half as many young as other eagles in Washington and Oregon.
learn more on topics covered in the film
see the video
read the script
learn the songs