State officials say all Utah Lake fish species should be tested for PCBs because carp in the lake are testing high in the toxin.

PCBs are Polychlorinated Biphenals, carcinogens that cause cancer in laboratory animals. Dennis K. Shiozawa, a BYU professor in the Integrated Biology department, said there are two major factors that could play in to the carp's toxicity, and both have to do with carp's diet.

"Because they are feeding along the bottom, they are ingesting more sediment," he said.

Once ingested by fish, PCBs accumulate in the fish's fatty tissues where they remain throughout the course of the fish's life. This further complicates the situation for carp because, in addition to eating aquatic plants along the lake bottom, carp also eat other fish and absorb whatever PCBs were present in the tissue of those fish.

"That's bioaccumulation," Shiozawa said.

Shiozawa said fish with longer life spans tend to accumulate more toxins than their short-lived counterparts. This presents a risk to the endangered June sucker, which is native to Utah Lake. The sucker often lives between 20 and 30 years and, if their food is tainted, they grow more and more contaminated with every meal.

State officials said in an advisory various fish species will be collected and analyzed this summer to determine PBC levels.

Jason Scholl, a toxicologist from the Department of Health, said the department has posted advisories at Utah Lake urging anglers to limit their consumption of carp from the lake to one serving per month.

Scholl said the carp tested low in Mercury and other chemicals. He said members of the June Sucker Recovery Implementation Program first realized the carp were high in PCBs when they were investigating ways to be rid of the fish. The recovery program was testing the carp to see if they were suitable for human consumption, animal feed or other uses. Scholl said carp are non-native and have depleted the June sucker population.

Scholl said the manufacture of PCBs has been outlawed since 1977 but residuals from previous decades have made their way into Utah Lake. He said PCBs come from man-made materials and are found in old electrical transformers and other industrial equipment.

Scholl said the risk to humans is if a person were to eat a lot of the fish often, they may increase the risk of cancer later on in life.

Laboratory research has shown PCBs cause cancer and neurological defects in laboratory animals that consume a toxic level of the substance, but it is unclear whether PCB toxicity will affect fish's ability to feed, function or reproduce.

Copyright Brigham Young University 24 May 2006