The scientists are now analyzing water samples from the South Branch and the Cacapon River -- a nearby Potomac tributary where intersex bass were also found. The chemicals they're looking for now are not the well-known pollutants that the state already tests for, such as nitrogen and phosphorus from manure and metals from mine runoff.
Instead, the culprit is probably in a class called "emerging contaminants," which includes everything from caffeine and prescription drugs to hormones excreted by livestock or humans.
The Potomac's South Branch in Moorefield, W.Va. The bass problem was found after reports of many fish dying with lesions.
(Ricky Carioti -- The Washington Post)
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Some of these pollutants have been linked to developmental problems in wildlife. Scientists believe that fish, especially, absorb hormones from other animals, as well as other chemicals that their bodies mistake for hormones.
One recent study near sewage plants in Colorado found male fish whose bodies were trying to produce eggs and some females whose reproductive systems were out of sync. Other studies have found similar effects from the hormones in cow manure and from chemicals from a wood-pulp plant.
"It is certainly an alarming situation that we're seeing more and more gross effects," said David O. Norris, a professor who worked on the Colorado study.
These emerging contaminants were hard to detect without the finely tuned equipment developed recently. The first nationwide survey, conducted in 1999 and 2000, found hormones in about 37 percent of the streams surveyed and caffeine in more than half.
The only testing in the Potomac, done in Washington in 2002, found low levels of caffeine, plus the insecticide DEET and chemicals produced when a body breaks down nicotine. There were also a few suspected endocrine disruptors, including chemicals found in hand soap and household cleaners.
As of now, little is done to test for these chemicals -- either in river water or in drinking water. The U.S. Environmental Protection Agency has not set standards, saying more research is needed to determine which contaminants are harmful and what levels are unsafe.
West Virginia, Virginia, Maryland and the District do not test river water regularly for drugs or hormones. The same goes for drinking water after it is processed by the Washington Aqueduct, supplying the District, Arlington County and Falls Church, and the Washington Suburban Sanitary Commission.
Still, the West Virginia study has spurred scientists to look for more information. Researchers at the U.S. Fish and Wildlife Service are seeking money for a much larger study across the Potomac watershed. They want to look for intersex bass and potentially disruptive chemicals in sites including the Blue Plains sewage plant in Southwest Washington.
Another federal study is underway in Rock Creek, looking for intersex symptoms and other health problems in a species of fish called white suckers.
Scientists across the region stressed that their work is just beginning. "We really don't know what's going on," said Vicki S. Blazer, a researcher for the geological survey in West Virginia.
