Fake fish used to check PCBs in Lake Anna

Researchers deploy high-tech devices to test reservoir for pollutants absorbed by fish.

By RUSTY DENNEN

Date published: 10/28/2004

By RUSTY DENNEN

Scientists plumbing the depths of Lake Anna for PCB contamination are getting some help from fake fish.

Earlier this month, researchers with the Virginia Department of Environmental Quality submerged 10 of the sensors in the lake and several of its feeder streams. The devices, which look more like half-gallon thermos bottles than bass or catfish, absorb pollutants in the water for 28 days.

The equipment approximates fish tissue, and analysis of the faux fish may indicate the level of PCB contamination in real fish. Unlike most fish, the fakes rest on the bottom.

Researchers have used the canisters, known as semipermeable-membrane devices, in streams elsewhere in Virginia, but the technology is relatively new.

Polychlorinated biphenyls, used in electrical transformer oils, were banned in the 1970s after being linked to cancer and nervous-system disorders. PCBs remain in the soil and sediment for decades after being released into the environment.

In August, the DEQ, the U.S. Army Corps of Engineers and the Lake Anna Civic Association launched an in-depth study of the cancer-causing chemical in the lake on the Spotsylvania, Louisa and Orange county lines.

The DEQ took about 30 sediment samples from the lake to test for the presence of PCBs and metals such as copper and mercury. Researchers hope to locate spots with high PCB levels and eventually determine the source.

"This will help us to identify areas of the lake that are more contaminated than other regions," said Roger Stewart, a DEQ environmental scientist.

Initial test results indicated the presence of PCBs in lake soils and elevated levels of copper, lead and zinc in the Contrary Creek arm of the 13,000-acre lake.

More detailed data on PCB soil levels will be released later.

In June, the state Health Department issued a fish-consumption advisory for carp in Lake Anna.

It was the first-ever fish warning for the lake, which was completed in 1972 to cool nuclear reactors at North Anna Power Station.

Carp are susceptible to PCB contamination because they are bottom-feeders.

Tests conducted last year by the DEQ found PCB levels exceeding the 600-parts-per-billion limit. Tests on five carp from the lake showed levels of 857 parts per billion.

To reach RUSTY DENNEN: 540/374-5431 rdennen@freelancestar.com

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Date published: 10/28/2004