State environmental officials yesterday relaxed their warning about eating fish caught in the upper Potomac River, saying there have been "substantial decreases" in dioxin contamination downstream from the Westvaco Corp. paper mill in Luke.
The move was immediately criticized by environmentalists, who contend that Maryland's limits on dioxin, a suspected human carcinogen, are too lax.
Citing new sampling results, the Maryland Department of the Environment dropped its nearly 2-year-old advice to limit consumption of bass and most other surface-feeding sport fish caught in the 40-mile stretch of the Potomac between Luke and Paw Paw, W.Va.
Fishermen are still being urged to avoid eating any bottom-feeding fish, such as channel catfish or bullheads, and to eat no more than 14 meals of sunfish in a year. Bottom-feeding fish are suspect because dioxin is concentrated in the mud of the riverbed.
No sunfish were caught for testing, and the advisory on them has not been eased.
Sampling of fish in the river last year below Westvaco revealed that dioxin levels in fish tissue have dropped considerably since June 1990, when the state first issued its health advisory. That warning came after unacceptable levels of dioxin were discovered in the skin and fatty tissue of fish caught there.
In the latest fish samples, taken in May and October, none of the sport fish contained detectable levels of dioxin, according to a statement issued by Environment Secretary Robert Perciasepe.
The sampling was conducted by a laboratory hired by Westvaco, but it followed procedures set by the state, environmental officials said.
Dioxin is a common byproduct of using chlorine in the paper bleaching process. But Westvaco, after making $15 million in modifications to the Luke mill, has reduced the amount of dioxin in its wastewater by more than 90 percent since 1988. The chemical has not been detectable in the plant's discharge into the Potomac since late 1989.
David Bailey, a lawyer with the Environmental Defense Fund in Washington, called the easing of Maryland's fish advisory "absurd."
Five environmental groups, including the Environmental Defense Fund, filed suit last year challenging the Environmental Protection Agency's approval of dioxin pollution limits set by Maryland and Virginia. The groups contend the states should not allow 100 times more dioxin to be discharged into rivers and streams than the EPA recommends.
The dioxin standard in Maryland and Virginia is 1.2 parts of the chemical per quadrillion parts of water. A quadrillion is 1,000 billion. EPA guidelines recommend a limit of 0.013 parts per quadrillion.