Concerns raised over fish pollution

Friday, June 5, 1998 | 10:15 a.m.

Southern Nevada water experts say they won't issue a warning to Lake Mead fishermen on how much pesticides and chemicals appear in the striped bass or catfish until more studies are completed.

The experts meeting Thursday as the Lake Mead Water Quality Forum questioned an 18-month study by the federal Environmental Protection Agency and said they had not seen enough results from 60 sports fish taken from the lake to issue any advisories.

Toxicologists reviewing the EPA's work said pesticides such as DDT and DDE have been found in fish tissues, but results from PCBs (polychlorintated biphenyls) have not been studied enough.

DDT and PCBs have been found in many city water supplies. The insecticide DDT and its byproduct DDE can persist for decades in the fat tissues of fish. PCBs, banned by the EPA in 1977 because of their cancer-causing potential, do not dissolve in water, but concentrate in the fat of fish and in the people who eat the fish.

The advisors said they did not know how often people eat fish caught in Lake Mead.

Those fishing in the lake once a week don't need to worry, said National Park Service biologist Bill Burke. However, eating Lake Mead fish every day could expose people to higher levels of pesticides, he said.

One 7-pound catfish showed higher levels of every chemical tested, Burke said. "The older and bigger the fish, the more accumulates in the tissue," he said. "Maybe it would be wise to stuff and mount the big catches."

Biologist Larry Paulson asked for another study using fresh fish and an independent laboratory.

"My common sense tells me we should retest those fish if we are to have any credibility with the public," he said. In more than 25 years of biological testing, Paulson said he never heard of taking such a long time with tissue studies.

The forum experts agreed to wait until the experts reviewing the EPA's work issue a final report later this year.