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By RUSTY DENNEN

New pollutants brewing in the Potomac River basin are creating fish with both male and female characteristics, and may be playing a role in fish kills.

As a result, more regulation of new chemicals is needed, along with study of the potential effects of "endocrine disrupters" on humans who are drinking the water.

Those are a few of the findings the Potomac Conservancy's State of the Nation's River report, released yesterday in a conference call with reporters.

The report, in its third year, focuses on the troubling discovery of intersex fish--mostly smallmouth bass--in the Potomac and Shenandoah rivers in Virginia and the Monocacy River in Maryland.

Vicki Blazer, a fish pathologist with the U.S. Geological Survey, was among scientists looking into fish kills in 2002 when male fish with eggs and female fish with reduced reproductive function turned up in the research.

"Since that finding, we've worked with West Virginia, Virginia and Maryland to address fish kills and intersex fish. More and more, as we look at it, both are associated."

She said that intersex fish also tend to have diminished immune systems, but she said that's not the whole picture.

"It is just one of the indicators, and the one that has attracted a lot of public attention. I don't believe we're going to find just one chemical or one source. What we're seeing is complex mixtures," Blazer said.

The contaminants enter waterways in the form of pesticides and fertilizers, industrial byproducts, agricultural and veterinary products, pharmaceuticals, per- sonal-care products and biosolids.

John Peterson Myers, chief scientist with Environmental Health Services in Charlottesville and co-author of a book on the subject, "Our Stolen Future," said the problem extends beyond fish and aquatic life.

"To put it in a broader context, first, it is clear that the patterns of contamination are important for wildlife," he said. Research is showing how "contamination, even at remarkably low levels, affect wildlife and is likely to be affecting people." That's significant because 90 percent of those living in the Washington area get their drinking water from the Potomac.

Plants that treat wastewater and filter drinking water are currently not removing many of the contaminants from water intakes or discharges into the river, the conservancy says.

Meanwhile, Myers said, methods of testing the safety of new compounds "are proving wholly inadequate," though government policy changes are on the horizon.

"This is the canary in the coal mine," said Potomac Conservancy President Hedrick Belin. "What's so challenging is that you don't see a river on fire. There's nothing washing up on the shore. It doesn't smell," and the problem is all but invisible.

"We feel the prudent course of action is to keep these pollutants out of the water, rather than trying to get them out after the fact."

He said the conservancy, a nonprofit land trust formed in 1993, is recommending:

Limitations on the introduction of new compounds.

Studying their effects on human health, including children.

Updating regulations to deal with the new pollutants in area rivers.

And requiring states and localities to adopt more stringent stormwater-management regulations.

Rusty Dennen: 540/374-5431
Email: rdennen@freelancestar.com

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