Male fish that are growing eggs have been found in the Potomac River in Maryland, a federal scientist said last week -- indicating that a troubling pollution mystery in West Virginia has spread downstream toward Washington. Nine male smallmouth bass, taken from the Potomac about 60 miles from the District, were found to have developed eggs inside their sex organs, said Vicki S. Blazer, a scientist overseeing this research for the U.S. Geological Survey.
News of the abnormal fish comes as authorities in West Virginia -- where the fish problem was first noticed in a Potomac tributary -- are investigating whether there is a link to higher rates of certain cancers in people there.
In both places, authorities say the Potomac's problems are likely related to a class of common but little-understood pollutants. These are spewed out by sewage plants, feedlots and factories, and they apparently are able to interfere with the natural hormone systems that guide all animals' development.
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The abnormal Maryland fish were caught near Sharpsburg in Washington County. Blazer, who works at a federal fish lab in West Virginia, said she examined their tissues on slides last week. "They all have intersex," Blazer said, using the scientific term for a condition in which animals have both male and female elements."
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http://www.washingtonpost.com/wp-dyn/articles/A10750-2004Dec18.html