Six years later, gender-bending fish in our water supply remain a mystery

By David A. Fahrenthold
Washington Post Staff Writer
Tuesday, November 24, 2009

KEARNEYSVILLE, W.VA. -- What's the problem with the Potomac River -- and could whatever it is spell problems for those of us who drink its water?

In 2003, scientists discovered something startling in the Potomac, from which at least 3 million Washington area residents get their drinking water: Male fish were growing eggs. But six years later, a government-led research effort still hasn't answered those two questions. Scientists say they still aren't sure which pollutants are altering the fish, or whether the discovery poses any threat to people's health.

The job is not easy: Scientists are looking for wisps of hormone-mimicking pollutants in the Potomac's vast, moving soup.

But the effort has also been held back, according to environmentalists and a federal researcher, by sparse funding and a lack of government focus.

The most tangible sign of the slow progress might be a frost-lined freezer at a government lab here in West Virginia. Inside are hundreds of samples of fish tissue collected from the Potomac in recent years, potential evidence that a federal scientist says she hasn't yet found the money to test.

"We'd be a couple years ahead" if the tissue had been tested, said Vicki S. Blazer, a biologist with the U.S. Geological Survey, who helped discover the Potomac's intersex fish.

There is still no evidence that whatever's affecting the Potomac's fish is a threat to humans who drink the river's tap water, which drinking-water authorities in the area say is filtered and safe.

Environmental activists have said they're surprised that such an attention-grabbing mystery -- gender-bending fish in the capital's water supply -- has languished so long without answers. On Wednesday, the nonprofit Potomac Conservancy spotlighted concerns about the fish in its annual "State of the Nation's River" report, saying the river held a "toxic stew" of chemicals that could mimic natural hormones.

"There's been some work done, but the pace of the research has been too slow," said Hedrick Belin, the group's president. "This canary in the coal mine, meaning the intersex fish, tells us that something isn't right with the water."

Which is exactly the kind of thing activists said after the first abnormal smallmouth bass were discovered in a West Virginia tributary in 2003. These fish don't look different on the outside, so the first ones were found by accident, as researchers investigated massive fish kills.

Under a microscope, they found that some male fish had nonfertile eggs inside their testes.

Since then, similar fish have been found all around the Potomac watershed. They have also been found across the United States. In a survey of nine other rivers this year, an average of 33 percent of male smallmouths were abnormal.

On the Potomac, the number is 82 percent.

Tests on Potomac water found it is contaminated with all kinds of chemicals that might be "endocrine disruptors," similar enough to natural hormones that they could confuse an animal's -- or a person's -- system of chemical signals. Some of them come into the river with treated sewage: human hormones, birth-control pills, chemicals in antibacterial soap.

Others wash off farm fields, such as the herbicide atrazine, the pesticide dieldrin, and cow and chicken hormones excreted in manure.

Blazer, the Geological Survey researcher, has a suspicion: that some of these pollutants accumulate in the tiny yolk sacs that are a baby fish's first food. If that's true, then male fish might be taking in chemicals similar to female hormones at a crucial time in their development.

But Blazer has not been able to test hundreds of pieces of dissected fish in the freezer to see whether pollutants, or mixtures of them, show up in crucial organs.

"It's $400 a tissue" to analyze them, she said, and so only about a third have been submitted for testing.

The Senate appropriated money specifically for this work in fiscal 2008, but it was dropped in conference committee, Geological Survey officials said. Last fiscal year, $400,000 was budgeted by the Geological Survey for analyzing intersex fish in the Potomac. One-third of that money went to Blazer; two-thirds went to other parts of the country, where scientists were doing research on similar problems with intersex fish in laboratories.

"To imply that the money is not being spent on issues related to the Potomac would be inaccurate," said Patti Bright, an official at the Geological Survey.

But Rep. James P. Moran Jr. (D-Va.) said the Potomac has been shortchanged. He is pushing for a doubling in Blazer's funding for the next fiscal year.

"It's kind of a Catch-22. Until we can have the resources to determine where it's coming from and how dangerous it is, it kind of stays on the back of the shelf," Moran said.

Until the mystery of the fish is solved, what -- if anything -- this problem means for people seems certain to remain uncertain.

Water from the Potomac is filtered and used for drinking in the District, Arlington County and Falls Church, and it provides at least some of the water in areas served by Fairfax Water, the Washington Suburban Sanitary Commission and the Frederick County water utility. These agencies say their treatment methods remove many potential endocrine disruptors. But a study of District tap water has found minute traces of some, including atrazine.

Water agencies say they don't think their customers need to filter their tap water.

"At Fairfax Water, we already have that filter in place for you" with treatment at the utility's plant, spokeswoman Jeanne Bailey said. "I drink our water every day." No home water filter has been certified to remove endocrine disruptors, but a spokesman for a national certifying organization has said reverse-osmosis and activated-carbon filters seem "promising."

One problem, water utilities say, is that the Environmental Protection Agency hasn't told them which chemicals might be endocrine disruptors or how much of them is enough to cause effects in humans.

The EPA has been charged with doing this since 1996. But the agency says it was slowed by the difficulty of the science: These chemicals are not as simple as poisons, since they might be harmful in very tiny quantities and their effects on a human body might not show up for months or years.

This fall, the EPA took a key step, describing for the first time how chemicals should be tested for endocrine-disrupting effects. But it might be two years before the first results come back.

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