04-05-2004, 06:42 PM
DENTON COUNTY, A small number of male fish in Denton County, Texas, are developing female characteristics because estrogen from prescription drugs is finding its way into local waters.
Traces of estrogen--from birth-control pills, hormone replacement therapy and other sources--that aren't absorbed in the body, flow through wastewater treatment plants and into the area's lakes, rivers and streams. The drugs could reduce the fish population by rendering some males unable to breed, researchers say. Others contend that fewer breeding males won't hurt the population.
The issue has raised worldwide interest as the U.S. Environmental Protection Agency now lists 477 research projects in the United States, and many more are under way in Europe.
University of North Texas researchers have found that some male fish now harbor compounds that are typically secreted by female fish before the production of egg yolk.
Investigators also found lower levels of testosterone in those male fish, says Brian Brooks, a Baylor University environmental science professor who conducted the research.
But most species can thrive without large numbers of males, says Jon Hemming, one of the authors of another study that appeared in the March issue of the Journal of Ecotoxicology and Environmental Safety.
Studies have also shown that the effects seem to lessen during the summer, when Denton's two universities are relatively unpopulated.
One theory is that the processes used by the treatment plant to scrub the wastewater free of contaminants work better during the summer, when more heat is added to the reactions. Hemming says this theory holds the most scientific weight.
The other theory is that the people excreting the prescription drugs on these unsuspecting fish and other aquatic life go elsewhere during the summer, lessening the concentrations of prescription drugs in the wastewater.
Although the EPA monitors several compounds considered hazardous to people and the environment, pharmaceuticals aren't on the list.
Research shows that only trace amounts of pharmaceuticals have been found in drinking water supplies. That research has shown that the concentrations would have to be much higher to cause a problem for people.
The Fort Worth water department has the city's wastewater checked periodically by an outside company to determine if the water has become toxic to wildlife, says Mary Gugliuzza, public education coordinator for the Fort Worth water department. The monitors determine whether the fleas and minnows have stunted growth patterns or reproductive cycles and whether they can remain alive in the environment.
New research into the problem will likely focus on streams and rivers that receive most of their water from sewage treatment facilities.
[signature]
Traces of estrogen--from birth-control pills, hormone replacement therapy and other sources--that aren't absorbed in the body, flow through wastewater treatment plants and into the area's lakes, rivers and streams. The drugs could reduce the fish population by rendering some males unable to breed, researchers say. Others contend that fewer breeding males won't hurt the population.
The issue has raised worldwide interest as the U.S. Environmental Protection Agency now lists 477 research projects in the United States, and many more are under way in Europe.
University of North Texas researchers have found that some male fish now harbor compounds that are typically secreted by female fish before the production of egg yolk.
Investigators also found lower levels of testosterone in those male fish, says Brian Brooks, a Baylor University environmental science professor who conducted the research.
But most species can thrive without large numbers of males, says Jon Hemming, one of the authors of another study that appeared in the March issue of the Journal of Ecotoxicology and Environmental Safety.
Studies have also shown that the effects seem to lessen during the summer, when Denton's two universities are relatively unpopulated.
One theory is that the processes used by the treatment plant to scrub the wastewater free of contaminants work better during the summer, when more heat is added to the reactions. Hemming says this theory holds the most scientific weight.
The other theory is that the people excreting the prescription drugs on these unsuspecting fish and other aquatic life go elsewhere during the summer, lessening the concentrations of prescription drugs in the wastewater.
Although the EPA monitors several compounds considered hazardous to people and the environment, pharmaceuticals aren't on the list.
Research shows that only trace amounts of pharmaceuticals have been found in drinking water supplies. That research has shown that the concentrations would have to be much higher to cause a problem for people.
The Fort Worth water department has the city's wastewater checked periodically by an outside company to determine if the water has become toxic to wildlife, says Mary Gugliuzza, public education coordinator for the Fort Worth water department. The monitors determine whether the fleas and minnows have stunted growth patterns or reproductive cycles and whether they can remain alive in the environment.
New research into the problem will likely focus on streams and rivers that receive most of their water from sewage treatment facilities.
[signature]