- Joined
- Mar 11, 2001
- Messages
- 70,011
- Reaction score
- 1,007
May. 19, 2003
SOMETHING FISHY
Drugs seeping into water give male fish female characteristics
By Mitch Mitchell, Dallas Star-Telegram Staff Writer
Darla Herrin, left, and Bill Hansbury, watershed protection technicians with the City of Denton, look for fish in the wetlands behind the city's water treatment plant Friday. STAR-TELEGRAM/RICK MOON
Some male fish in Denton County may soon be swimming in an all-girls' school.
A small number of male fish are developing female characteristics because estrogen from prescription drugs is winding up in their water. Prozac is, too, but perhaps that could help the fish deal with their life changes.
"The male fish may be turning into females," Denton water resources manager Ken Banks said, "but at least they're pretty calm about it."
Stop laughing, this is serious.
Traces of estrogen -- from birth control pills, hormone replacement therapy and other sources -- that are not absorbed into the body, flow down the toilet, 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, some researchers say. Others contend that fewer breeding males won't hurt the population.
The issue has raised worldwide interest. The U.S. Environmental Protection Agency 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, said Brian Brooks, a Baylor University environmental science professor who conducted the research while he was a UNT graduate student. He also helped author a study on the effects of Prozac on aquatic organisms in Denton County.
"We are also seeing higher levels of secondary sexual female characteristics in these male fish," Brooks said. "The male fish are actually being demasculinized."
But most species can exist just fine without large numbers of males, said Jon Hemming, one of the authors of another study that appeared in the March issue of the Journal of Ecotoxicology and Environmental Safety.
"The fitness of the female population is much more important than the fitness of the male population," Hemming said. "You need only a few males to maintain biological diversity."
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 in the summer, when more heat is added to the reactions. This theory holds the most scientific weight, Hemming said.
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.
"We do have two major universities, and we do have a population that fluctuates depending on school being in or out," Banks said.
Although the EPA monitors several compounds considered hazardous to people and the environment, pharmaceuticals are not 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 that uses water fleas and flathead minnows to determine if the water has become toxic to wildlife, said 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, Gugliuzza said.
New research into the problem will likely focus on streams and rivers, such as the Trinity River, that receive most of their water from sewage treatment facilities, Brooks said.
Many investigators suggest it is a serious problem or, at the least, potentially serious, he said.
"But I think there is still some work that needs to be done before we can say that for sure," Brooks said.
--------------------------------------------------------------------------------
ONLINE: http:/epa.gov/nerlesd1/ chemistry/ppcp/images/green1.pdf
Mitch Mitchell, (817) 685-3807 mitchmitchell@star-telegram.com
SOMETHING FISHY
Drugs seeping into water give male fish female characteristics
By Mitch Mitchell, Dallas Star-Telegram Staff Writer
Darla Herrin, left, and Bill Hansbury, watershed protection technicians with the City of Denton, look for fish in the wetlands behind the city's water treatment plant Friday. STAR-TELEGRAM/RICK MOON
Some male fish in Denton County may soon be swimming in an all-girls' school.
A small number of male fish are developing female characteristics because estrogen from prescription drugs is winding up in their water. Prozac is, too, but perhaps that could help the fish deal with their life changes.
"The male fish may be turning into females," Denton water resources manager Ken Banks said, "but at least they're pretty calm about it."
Stop laughing, this is serious.
Traces of estrogen -- from birth control pills, hormone replacement therapy and other sources -- that are not absorbed into the body, flow down the toilet, 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, some researchers say. Others contend that fewer breeding males won't hurt the population.
The issue has raised worldwide interest. The U.S. Environmental Protection Agency 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, said Brian Brooks, a Baylor University environmental science professor who conducted the research while he was a UNT graduate student. He also helped author a study on the effects of Prozac on aquatic organisms in Denton County.
"We are also seeing higher levels of secondary sexual female characteristics in these male fish," Brooks said. "The male fish are actually being demasculinized."
But most species can exist just fine without large numbers of males, said Jon Hemming, one of the authors of another study that appeared in the March issue of the Journal of Ecotoxicology and Environmental Safety.
"The fitness of the female population is much more important than the fitness of the male population," Hemming said. "You need only a few males to maintain biological diversity."
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 in the summer, when more heat is added to the reactions. This theory holds the most scientific weight, Hemming said.
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.
"We do have two major universities, and we do have a population that fluctuates depending on school being in or out," Banks said.
Although the EPA monitors several compounds considered hazardous to people and the environment, pharmaceuticals are not 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 that uses water fleas and flathead minnows to determine if the water has become toxic to wildlife, said 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, Gugliuzza said.
New research into the problem will likely focus on streams and rivers, such as the Trinity River, that receive most of their water from sewage treatment facilities, Brooks said.
Many investigators suggest it is a serious problem or, at the least, potentially serious, he said.
"But I think there is still some work that needs to be done before we can say that for sure," Brooks said.
--------------------------------------------------------------------------------
ONLINE: http:/epa.gov/nerlesd1/ chemistry/ppcp/images/green1.pdf
Mitch Mitchell, (817) 685-3807 mitchmitchell@star-telegram.com
