Local catfish found to be missing genitalia
Dan Volz noticed something missing as he dissected channel catfish caught in the water off Point State Park -- their genitalia.
"It was kind of like a streak of tissue, and we couldn't tell whether it was male or female," said Volz, a University of Pittsburgh Graduate School of Public Health professor who is leading a project to test local fish for contaminants. About 25 percent of the catfish Volz dissected couldn't be categorized as male or female.
Extract from fish caught in Western Pennsylvania's rivers showed unnatural levels of materials that mimic the female hormone estrogen. When "fed" to breast cancer cells in the laboratory, the extract more than doubled the rate of cancer growth, according to a study presented Tuesday at the American Association for Cancer Research in Los Angeles.
One concern is that much of the region's drinking water comes from the rivers.
"We chose fish to look at because they're better at showing whether there is a problem in the river than actually even measuring chemicals in the water, because (fish) accumulate these chemicals," Volz said. "They can serve as sentinels for problems related to contaminants in our drinking water."
The U.S. Environmental Protection Agency does not require that drinking water be tested for estrogen or that the hormone be removed. Western Pennsylvania's drinking water is not tested for estrogen, said Stan States, the water quality manager for the Pittsburgh Water and Sewer Authority.
There is a statewide advisory against eating more than a half-pound of fish caught in Pennsylvania waters each week because of the risk of unidentified contaminants. Catfish from the Allegheny River in Allegheny County should be eaten only once a month, and catfish from the Ohio and Monongahela rivers in Allegheny County never should be eaten.
Fish with indistinguishable genitalia and unnatural estrogen levels have been found in many other rivers, including the Detroit River in Michigan and Potomac River in West Virginia.
The Pitt research is part of a larger project to look for contaminants in Western Pennsylvania's rivers. Local fishermen caught 132 channel catfish and white bass in the Ohio River near Point State Park, the Monongahela River near the Braddock Dam and the Allegheny River near the Highland Park Dam and in Kittanning.
Volz said industrial waste and municipal sewage -- which contains birth control and hormone replacement therapy drugs -- are likely sources for the estrogen-mimicking chemicals found in the fish.
A random sample of 25 of the fish caught were tested for estrogen and their effect on cells from a type of breast cancer that responds to the hormone. Extract from five of the 19 catfish sampled and six of the bass caused the cancer to grow.
"In some cases ... estrogen was present (in the fish) in levels similar to a woman's natural hormone levels," said Patricia K. Eagon, an associate professor in Pitt's School of Medicine, who tested the fish.