Drugs in Drinking Water: Are antibiotic-resistant superbugs evolving? (EH Update).

Approximately 20 years ago, researchers from the U.S. Environmental Protection Agency (U.S. EPA) were examining sludge from a wastewater treatment plant and discovered that it contained excreted aspirin, caffeine, and nicotine. A short time after that, the cholesterol-lowering drug clofibric acid was detected in a groundwater reservoir in the Phoenix, Arizona, area.

Now, new studies indicate that water throughout the United States and the world contains traces of prescription antibiotics, painkillers, anti-inflammatory compounds, anti-convulsive medications, cancer-treatment agents, psychiatric remedies, and oral contraceptives. In some cases, from 50 to 90 percent of a pharmaceutical drug is excreted from the body in its biologically active form.

The American Chemical Society addressed the issue of pharmaceuticals in water at a symposium in September 2000. Christian G. Daughton, chief of chemistry at U.S. EPA's National Exposure Research Laboratory in Las Vegas, spoke at the event and said that water polluted with drugs is a "newly emerging issue" for the agency.

Currently, scientists do not have enough information to predict the effects of these drug traces on human health or the ecosystem. They do, however, have great concerns about antibiotics. Many scientists believe that overprescription, patient misuse, and agricultural overuse are the primary factors driving the growing resistance of bacteria to antibiotics.

Some experts believe that even low levels of antibiotics in water supplies may lead to superbugs--microorganisms that have evolved to survive antibiotic assault. Public-health officials have already found that the recent rise in infections cannot be stopped with the usual arsenal of antibiotics.

Not only has U.S. EPA found antibiotics in numerous waterways, but the U.S. Geological Survey also has found antibiotics in many water samples taken from streams across the nation.

These findings "raise a big red flag," says Stuart Levy at Tufts University in Boston. Even though the antibiotics aren't harmful on their own, Levy and others fear that water laced with these drugs might breed microorganisms that shrug off the effects of wonder drugs such as penicillin.

According to Abigail Salyers, an expert on antibiotic resistance at the University of Illinois at Urbana-Champaign, "Superbugs may be causing tens of thousands of deaths in the United States each year."

For more information about drugs in drinking water, readers can contact U.S. EPA's Safe Drinking Water Hotline at [phone]. (Adapted, with permission, from On Tap, Vol. 1, No. 2, 2001.)