Hearth & Home

Down the Drain

Medicines and other chemicals are creating new headaches

By Joan Conrow

Most of us give little thought to what we’re washing down the drain and flushing down the toilet as we go about our daily ablutions. Over the years, it has been big industry’s products and byproducts–DDT, PCBs, and chlorinated dioxins–that captured our attention. But scientists are now discovering that our wastewater contains a whole host of chemicals found in the drugs, toiletries, and household products we use each day.

Don Wilkison, a U.S. Geological Survey hydrologist who has been monitoring streams in Kansas City, Missouri, regularly finds aspirin, nicotine, caffeine, antibacterial agents, and an array of other household chemicals and drugs in his midwestern water samples. Sewage treatment plants aren’t filtering out many of these contaminants, according to studies done in the United States, Europe, and Canada. And as wastewater is released into oceans, lakes, and streams, these chemicals–dubbed PPCPs (pharmaceuticals and personal-care products)–are dumped right along with it. Compounds like antibiotics also enter the environment through runoff from animal farming operations, the use of sewage sludge as fertilizer, and the practice of pumping treated effluent into the ground to replenish aquifers.

Advances in chemical analysis are enabling scientists to scrutinize water for a wider range of substances, and at lower concentrations, than ever before. They have detected PPCPs in locations as varied as alpine lakes, urban streams, and even drinking water. "We don’t make the connection between what we do on a day-to-day basis in our homes and the health of the nation’s rivers," says Wilkison. "Red flags should be going up." The toxicological and biological effects of these compounds are not well understood. "And when you think of aquatic organisms constantly being bathed in a pharmacopoeia of unknown and changing concentrations," he adds, "I think we should have some concerns."

Studies have been under way in Europe for a decade, but it wasn’t until 1999 that the U.S. Geological Survey launched a two-year nationwide water-sampling project. The study found prescription and over-the-counter antibiotics–as well as antibiotics used on farm animals–in waterways around the country. Such drugs can kill healthy and ecologically important bacterial organisms and contribute to drug-resistant bacterial strains. Wilkison says he was alarmed to find extremely low bacterial counts in streams that also showed high concentrations of triclosan, an antibacterial agent broadly used in soaps, detergents, sponges, and cutting boards.

Another area of concern is synthetic steroids and estrogenic drugs, which are used in hormone-replacement therapy, oral contraceptives, and athletic-performance enhancers and are frequently found in surface water fed by sewage effluent. Sexual changes have been noted in aquatic organisms exposed to these hormones.

Recent studies, such as those conducted by Chris D. Metcalf of Trent University in Ontario, Canada, and Ira Adelman of the University of Minnesota, indicate that such hormones can affect aquatic animals at extremely dilute concentrations, in the parts per trillion range. Even so, the Food and Drug Administration still doesn’t require a new drug to undergo an environmental assessment unless its manufacturer anticipates ecological concentrations of at least one part per billion.

Dana Kolpin, who coordinated the USGS survey, also suspects that second-hand exposure to these chemicals could affect human health, especially among children and pregnant women. He says new analytical tools will enable chemists to look at the cumulative and synergistic effects of some of these chemicals. "To fully understand the impacts," says Kolpin, "we will have to look at that broader picture."

Because of the sparse scientific data, it may be premature to tell people to stop using certain substances, says Christian Daughton, an ecotoxicologist with the EPA. Even so, Daughton and others agree that it’s wise to reduce the introduction of PPCPs into the environment. Government can help by upgrading outdated sewage-treatment facilities and developing better guidelines for disposing of pharmaceuticals. But most of it comes down to the choices we make at the drugstore and supermarket. It’s time to start perusing our medicine chests and reading the labels on our favorite toiletries and cleaning products. Sometimes we can substitute natural items; for example, a rock crystal sold in health-food stores can replace chemical-laden deodorant. Eco-friendly detergents and household cleaners are all readily available. Selecting free-range and organic meat and poultry discourages drug-dependent livestock farming. We can also stop using certain products altogether. Only you can decide if you really need fabric softener, shaving cream, perfume, antibacterial soaps, odor-eating shoe inserts, mouthwash, or any of the hundreds of other products that we have come to accept, often without questioning, as an essential part of everyday life.

Joan Conrow is a writer based in Kilauea, Hawaii.

You can read the USGS study "Pharmaceuticals, Hormones, and Other Organic Wastewater Contaminants in U.S. Streams, 1999—2000: A National Reconnaissance" at http://pubs.acs.org/journals/esthag/36/i06/pdf/es011055j.pdf.