Does it matter that pharmaceuticals are turning up in water supplies?

Suspecting that they might have found the pesticide in an early stage of degradation, Hans-Rudolf Buser and Markus D. Müller probed further. To their surprise, the pollutant turned out to be clofibric acid, a widely used cholesterol-lowering drug.

Immediately, the pair began scouting for the drug elsewhere -- and they found it everywhere, from rural mountain lakes to rivers flowing through densely populated areas.

The ubiquity of clofibric acid, which is not even manufactured in Switzerland, argued against the possibility that the contamination stems from some industrial accident or spill. The only reasonable explanation is that it comes from human wastes.

Though the body tends to break down any medicine it uses, how effectively it does so can vary widely -- by individual and by drug. As a result, in some cases, 50 to 90 percent of an administered drug may be excreted from the body in its original or its biologically active form. In other cases, partially degraded drugs are converted back into their active form through chemical reactions with the environment.

Like the Swiss team, the Berlin scientists went on to find clofibric acid throughout local waters. It also turned up in all the Berlin tap water they sampled.

When it comes to waterborne drugs, however, clofibric acid is just the tip of the iceberg. Heberer and Stan are part of a Berlin research team that has found drugs for regulating concentrations of lipids in the blood and analgesics (including ibuprofen). Other researchers have detected chemotherapy drugs, antibiotics, and hormones in bodies of water that supply drinking water.

What do low concentrations of these drugs in water mean? Do they pose a health risk to people? Can they harm wildlife or substantially alter aquatic ecosystems? Do they foster the buildup of resistance to antibiotics?

For now, there are no answers.

Drugs, however, have come to be regulated by health departments, which possess little expertise in protecting natural ecosystems and water supplies. Moreover, they tend not to look at pharmaceuticals as potential pollutants -- even though up to 90 percent of a delivered drug may leave the body in urine and feces.

Regulators have attempted to cope with this problem by asking manufacturers to model a new drug's projected concentration in public water supplies.

In the United States, an environmental assessment containing such estimates would be submitted to the Food and Drug Administration as part of the approval process for a new drug, explains Dabial C Kearns of the FDA in Rockville, Md..

So seldom did an environmental assessment for a new drug suggest a hazard, however, that the FDA decided last July to reduce a manufacturer's environmental reporting requirements. The agency concluded that excreted drugs "are probably not having a significant environmental effect, so unless modeling data suggest a drug's concentrations would reach 1 ppb, a manufacturer no longer must submit an environmental assessment.

When asked whether FDA requires any monitoring of water supplies to see whether concentrations in the real world match the predictions of drug manufacturers' models, Kearns said no.

Thomas A. Ternes, a chemist with the municipal water research laboratory in Wiesbaden, launched a water-monitoring project to look for drugs in sewage, treated water, and rivers. He detected 30 of the 60 common pharmaceuticals for which he tested. These included lipid-lowering drugs, antibiotics, analgesics, antiseptics, and beta-blocker heart drugs. He has even found residues of drugs to control epilepsy and ones that serve as contrast agents for diagnostic X rays. .

Ternes detected parts-per-billion concentrations of these drugs in both raw sewage and the water leaving treatment plants. "We also found these compounds in nearly all streams and rivers in Germany," he says.

These findings are not all that surprising," observes James F. Pendergast, acting director of the Environmental Protection Agency division that regulates what comes out of sewage treatment plants. For quite a while, he notes, water quality engineers have recognized that one of the highest-volume contaminants emerging in effluent -- especially early in the morning -- is caffeine, a drug excreted by all those people who down a cup or two of Java to jolt their bodies awake.

Although he was unfamiliar with the new European studies documenting drugs in water, Pendergast says that he has no reason to doubt their findings or the possibility that they might herald what could be found in U.S. waters, if anyone were to look.

The issue of drugs in water, he concludes, "is certainly an area where we could use a lot more science." To date, he notes, "information on hazards at the nanogram level just hasn't been developed."

A few laboratories stand poised to try. Snyder's assays, for instance, indicate that estradiol in water can reach 20 ppt -- a concentration that can cause some male fish to produce an egg-making protein normally seen only in reproductive females.

Parts-per-trillion concentrations of these drugs can affect Escherichia coli and other bacteria. The 1,000 times higher concentrations reported in German wastewater suggest "these antibiotics may be present at levels of consequence to bacteria -- levels that could not only alter the ecology of the environment but also give rise to antibiotic resistance."

By quantifying the potential ecological effects of individual compounds, he says, "we may get information that's useful for decision making.