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Are Our Medicines Tainting the Environment?

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WebMD Health News

June 2, 2000 -- To those schooled in the ways of water purification, it makes perfect sense. But it's a fair bet many Americans will find distressing the notion that residues from therapeutic drugs may be afloat in the nation's drinking water sources -- and that they could be coming from sewage.

Italian researchers discovered that might be the case in their country. They found a variety of drugs showing up in river water and sediment, and a few even drifting into sources of drinking water -- in all cases, just tiny concentrations. The results of their research appear in the British medical journal The Lancet and confirm studies done elsewhere in Europe during the past 10 years.

Perhaps the most striking thing about the latest research is that about half of the 16 drugs the researchers tested for shared a single characteristic: excretion from the human body in an unchanged form, which could mean they came from sewage. Other drugs that were included in the analysis are known to undergo breakdown in the body; their presence in the water supply suggests possible additional sources for the pollution -- improper disposal, for example.

Either way, the results suggest that the widespread use of therapeutic drugs isn't being lost on the environment, though experts say it's not clear what it all means. "My personal opinion is that any risk to humans is much less than for aquatic [plants and animals]," says Christian Daughton, PhD, chief of the Environmental Protection Agency's National Exposure Research Laboratory in Las Vegas. "There's practically nothing known about what can happen with aquatic life. Is it possible they are having an effect, but we're really not noticing it at this time?"

In other words, are drug residues causing subtle, but potentially devastating, effects on marine life? One example of a drug that might have such effects is verapamil. Daughton says the drug, used for cardiovascular ailments in humans, might harm the primary line of defense that some organisms have against water pollutants. Similar drugs might also affect animals' sperm viability, he says, while the class of antidepressants that includes Prozac has actually been found to increase spawning.

Daughton says some might ask: Aren't drug residues degradable? "Sure, they might be," he says. "But you're constantly introducing them. So these aquatic organisms are exposed 24 hours a day to these chemicals for their entire life span."

And even very small amounts of some drugs might make a difference, experts say. "The interesting thing about pharmaceuticals is that sewage treatment plants don't do anything to remove them," says Bob Morris, MD, PhD, an environmental epidemiologist and associate professor in the department of family medicine and community health at Tufts University in Boston. "And second, these are chemicals specially designed to have an effect on humans at low levels -- and that's what makes this story interesting."

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