High Level of PCBs Taints Lake Washington FishSep 1, 2004 | Seattle Times
Some of the most popular sport fish in Lake Washington contain surprisingly dangerous levels of toxic chemicals called PCBs, state health officials said yesterday, warning anglers to limit their consumption.
People should not eat large perch or cutthroat, which are among the most commonly caught fish in the lake, more than once a month, officials said. For cutthroat under 12 inches, the recommended maximum is three meals a month, and for perch under 10Â½ inches, no more than four meals monthly.
The Washington Department of Health also warned people never to eat the lake's northern pikeminnow, also known as squawfish. Though not favored by many anglers, pikeminnows collected in the lake contained up to 1,000 parts per billion (ppb) of PCBs â€” the highest level ever measured in any Washington fish species, said health department toxicologist Dave McBride.
PCBs are suspected human carcinogens, and consumption of tainted fish has been linked to learning deficits in children.
At least one sport species did get a clean bill of health from the preliminary testing, he added: Levels of PCBs in sockeye salmon were very low and pose no health risk.
The pikeminnows, yellow perch and cutthroat tested also were tainted by lower levels of mercury and pesticides, including DDT.
"It all came as a surprise," said McBride. "This is definitely old stuff, because PCBs and DDT have been banned for several decades."
Officials don't know where the contaminants are coming from, though they suspect a combination of urban runoff and pollution from industries once located around the lake.
"There's no single hot spot, or source," McBride said. "But historically, there have been a great number of different activities on or near the lake, from industry to shipbuilding, aerospace, military facilities, solid-waste disposal."
PCBs, DDT and mercury all can persist in the environment for long periods of time and tend to concentrate in animals higher up the food chain.
That's why the levels in pikeminnows were so high, said Dave Beauchamp, a University of Washington fisheries professor who was involved in collecting the data with graduate student Jenifer McIntyre.
"They're top predators and they can live up to 20-plus years."
Cutthroat contained an average of 375 ppb of PCBs, while yellow perch averaged 191 ppb, McBride said.
All are well above the generally accepted safe levels of 50-100 ppb, which is why health officials decided to issue the warning, even though the total number of fish sampled was very small, McBride said. McIntrye collected and analyzed 82 fish.
The PCB concentrations are for the whole fish.
"We realize the concentrations we are seeing are probably more elevated than what we would see if people were eating only fillets," McBride said.
Jerry Beppu, who for 40 years has operated Linc's Fishing Tackle on Rainier Avenue, said he is skeptical of the warning and doubts anglers will heed it.
"I have guys that go down there and catch their fish and eat it daily, especially perch," said Beppu, whose shop is a regular bait stop for many Lake Washington anglers. "I don't think they're going to stop because of somebody telling them there's PCBs in there."
Last year, the state warned pregnant women and children to limit consumption of smallmouth and largemouth bass from all state lakes, including Lake Washington, because of mercury contamination.
The Health Department is asking other agencies, including the federal Environmental Protection Agency, to help pay for a more thorough examination of contaminant levels in Lake Washington fish.
Last year, the Legislature cut funding for a state Ecology Department program to measure toxin levels in fish.
Each PCB analysis costs $500-$1,000, McBride said, and the agency hopes to test at least 100 more fish.