Traces of antidepressant found in bluegills in Texas creek

October 17, 2003
by Scott Streater
Fort Worth Star-Telegram
Knight Ridder Newspapers


FORT WORTH, Texas-(KRT) - Researchers at Baylor University have found traces of a pharmaceutical antidepressant in the livers, muscles and brains of bluegills in a Denton County, Texas, creek, raising concerns about the welfare of the popular sports fish and the people who eat them.

The chemical is fluoxetine - the primary component in Prozac. It likely came from a city of Denton wastewater treatment plant, which discharges into Pecan Creek and flows into Lake Lewisville in North Texas. Traces of the drug that are not absorbed into the body can flow down the toilet and through wastewater treatment plants, which are not designed to filter out pharmaceuticals.

Fluoxetine and other antidepressants affect fish in roughly the same ways they affect people, said Bryan Brooks, a Baylor toxicologist who led the study.

It relaxes them.

"Maybe it makes you a happy fish and you're kind of hanging out," Brooks said. "But how does that influence your ability to capture prey? Do you instantly become candy for large-mouth bass because you're accumulating large amounts of Prozac in your system? These are areas where more research is needed."

Brooks will present the results of his study next month in Austin, Texas, at the annual meeting of the Society of Environmental Toxicology and Chemistry.

It's believed to be among the first studies to show that antidepressants in the water can accumulate in biological tissue, raising the possibility of long-term health and behavioral problems in fish, said Marsha Black, an aquatic toxicologist at the University of Georgia at Athens.

"That's really a significant finding," said Black, who's using a federal grant to study the health effects of fluoxetine and other antidepressants in fish. "This opens up the door and says these things are important."

Brooks' latest research comes on the heels of recent studies he helped conduct while a graduate student at the University of North Texas. That research found that some male fish in Denton County are developing female characteristics because estrogen from prescription drugs is winding up in the water. The estrogen - from birth control pills, hormone replacement therapy and other sources - could reduce the fish population by rendering some males unable to breed.

The issue has garnered national attention in the last few years. A U.S. Geological Survey study last year found that 80 percent of the 139 streams it sampled in 30 states, including Texas, contained small amounts of pharmaceutical drugs, hormones, steroids and personal-care products like perfumes.

"It's very common," said Herbert Buxton, coordinator of the Geological Survey's Toxic Substances Hydrology Program. "What this tells us is that these wastewater pathways are worthy of a lot more study."

Brooks' study raises more questions than answers. Among them:

Can these pharmaceuticals pollute drinking water supplies?

What are the health effects of eating fish contaminated with pharmaceuticals?

If fluoxetine is in the bluegills in Pecan Creek, might it also be in the biological tissues of other species in other waterways?

Brooks said he has already expanded the research to include catfish and black crappie.

He said Pecan Creek was chosen as the site of his study because it receives as much as 13 million gallons a day of treated wastewater from Denton's Pecan Creek Water Reclamation Plant.

During the dry summer months, the wastewater from the plant comprises all of the creek's water flow, said Kenneth Banks, Denton's water resources programs manager.

Brooks said the pharmaceuticals in the creek are coming from the wastewater plant.

"I think it's got to be," he said.

Pecan Creek drains into Lake Lewisville, which supplies drinking water to the cities of Dallas, Denton and Lewisville. But researchers say it's extremely unlikely the antidepressant could get into drinking water wells, in part because the wastewater plant is several miles from the lake.

"After that distance it's virtually impossible that it would show up in potable water supplies," Banks said.

Federal and state environmental regulators do not regulate pharmaceuticals in water. The reason is that it has not yet been proven to harm fish and other aquatic life.

The results of research by Brooks and other scientists could change that. The Environmental Protection Agency is currently studying whether to develop formal recommendations for disposing old drugs to keep them out of the water. And the Food and Drug Administration is considering similar action.

If it can be confirmed that pharmaceuticals are moving untreated through wastewater plants, sewer plant operators may soon be required to begin controlling these discharges. This could necessitate adding new technology costing millions of dollars.

That could have a tremendous impact in North Texas.

The Trinity River basin, which runs from north of Fort Worth-Dallas to near the Houston metropolitan area, is the most developed watershed in the state, with numerous large wastewater treatment plants.

The Trinity River Association, a public utility created by the Legislature in 1955, operates four large wastewater treatment plants in North Texas that discharge into the watershed.

"It's very early, but the implications are potentially serious," said Richard Browning, senior manager of the Trinity River Association's planning and environmental management division.

"If they come out with a clear connection, then everybody will be looking at how to get it out of the water, then the regulations would flow very quickly."