Sunday, May 4, 2008; N04

By now you've probably heard this bit of eco-news: Whether or not you take prescription drugs, you're drinking them anyway.

A host of U.S. studies have found pharmaceuticals in drinking water and in the waterways and reservoirs that supply it. The Associated Press recently found that the D.C. area's supply includes trace amounts of such drugs as ibuprofen, naproxen and antibiotics.

Though a glass of water from the tap won't harm you -- "concentrations are thousands of times lower than therapeutic doses," says Edward Bouwer, chairman of the Department of Geography and Environmental Engineering at Johns Hopkins University -- more research is required to determine the cumulative effects of pharmaceutical exposure.

"It's certainly not alarming," Bouwer says. Still, it leaves you wondering how this happened and what you should do. Some things to consider:

Dispose of medicines properly. Most municipal wastewater treatment plants are not equipped to filter out pharmaceuticals, which enter the sewer system when people flush unused medications down the toilet (which has been the norm for decades in hospitals) or excrete them. Sending medications to the landfill, while a better option than flushing, still could cause the drugs to seep into groundwater. Seal the medication thoroughly and place it within multiple layers of other materials before tossing it in the trash.

Try to turn in your pharmaceuticals. Some communities have implemented take-back programs in cooperation with pharmacies, notably in Northern California. Locally, things aren't as easy or clear-cut, and agencies vary in helpfulness; contact your city or county household hazardous waste service for details. You could also ask -- and urge -- your pharmacy to begin a take-back program.

Don't switch to bottled water."Since our bottled water comes from the same aquifers and municipal water systems as our tap water, and since [most] bottled water is not even tested for these chemicals, switching to bottled water makes no sense," says Colin Beavan, who writes the eco-blog No Impact Man. Besides, residue from the bottles themselves may be worse than whatever lurks in tap water, not to mention the carbon footprint and plastic waste created in their manufacturing.

Keep it in perspective. Prescription drugs in water, says Susan Bruninga, director of legislative and public affairs for the National Association of Clean Water Agencies, "have always been there; we just have better methods of detecting them now." It's also worth keeping in mind that chemicals, including bad ones, lurk in air, food and furniture -- not just water. "Whatever poisons and chemicals we put in the habitat are eventually going to end up in our bodies," Beavan says. "It is not separate from us."

-- Eviana Hartman