Up a chemical creek. (Water Pollution).

A federal agency's survey of 95 chemicals in U.S. rivers and streams has unveiled what the survey's leader calls "a real cocktail of various compounds." The chemicals studied included antibiotics, other prescription drugs, pesticides, and household chemicals such as detergents and fragrances. The U.S. Geological Survey (USGS) found median concentrations that usually were relatively low, but some maximum concentrations were high and occasionally exceeded regulatory guidelines for the few such chemicals that have them. This study of everyday products in U.S. waters, the most extensive conducted so far, adds to the growing body of information on the topic, which includes work published in EHP Supplements in December 1999.

The sample sites aren't necessarily representative of the country's waterways. Most samples were taken immediately downstream from suspected pollution sources, such as wastewater treatment plants, urban areas, or agricultural operations. However, eight were taken in less-polluted settings.

The chemicals chosen for the USGS study were known to be used in significant quantities, were suspected of being in the environment and affecting environmental health, and could be cost-effectively evaluated at low concentrations. The study, which ran through 1999 and 2000 and was published in the 15 March 2002 issue of Environmental Science & Technology, focused on establishing the first snapshot of concentrations of the selected chemicals; it made no attempt to assess the implications of the findings regarding human health or ecologic systems.

At each of 139 sites in 30 states, one composite sample was drawn from 4-6 strata within a cross-section of the waterway. Of the 95 chemicals evaluated, 82 showed up in at least one sample. A mixture of 7 or more showed up in 50% of the streams, and 34% of the streams revealed a mixture of 10 or more.

The chemicals found most frequently were steroids (from plant and animal sources), caffeine, and components of insect repellent, disinfectants, and fire retardants. The median concentration detected for each group of chemicals was always less than 1.0 [micro] g/L, but some individual samples were much higher. The maximum reading for detergent metabolites was 55.6 steroids reached a peak of 18.3 [micro] g/L, and plasticizers topped out at 17.4 [micro] g/L.

While little is known about the environmental health effects of many of the chemicals, 46 are known to be pharmacologically active, and 33 are known to be hormonally active. That's a particular concern to Rebecca Goldburg, a senior scientist with the advocacy organization Environmental Defense, because she says such substances can have a biologic impact at very low doses. But Mark Grayson, senior director of public affairs for the Washington, D.C.-based Pharmaceutical Research and Manufacturers of America, says his organization maintains its position that no adverse environmental effects have ever been proven at these concentrations. U.S. Food and Drug Administration spokesman Brad Stone says the study causes his agency no immediate concern, but that the agency is reviewing the findings to determine if any targeted follow-up studies are needed.

USGS researchers are analyzing their data to better understand their nuances, such as the differences between urban, agricultural, and more naturalistic sites, and hope to publish their findings by the beginning of 2003. Two of their parallel studies, one of chemical contaminants in wells and another of surface and groundwater drinking sources, also are under way and may be published in the same time frame.

The USGS has a five-year plan for similar studies, looking at many of the issues that were ignored or only touched upon in this study. Potential topics include specific pathways of contamination, daily and seasonal variations in concentrations, degradation products of chemicals, and concentrations in sediment and the atmosphere. In addition, Dana Kolpin, the study's project chief and a research hydrologist with the USGS Toxic Substances Hydrology Program, says his team already is able to test for more than two dozen additional chemicals.

But President Bush's fiscal year 2003 budget cuts the entire $13.9 million budget for the Toxic Substances Hydrology Program. "It's possible this project may get terminated," Kolpin acknowledges. The potential trade-off is a $10 million boost in research through the National Science Foundation. But USGS insiders think government agencies are unlikely to use those monies, because federal salaries aren't covered by such funds. However, Congress may reinstate the USGS funding, as it did last year.

Other organizations are picking up the ball on some of the angles covered in this study. Researchers at The Johns Hopkins University announced in April 2002 that with a three-year $525,000 grant from the U.S. Environmental Protection Agency they are beginning to look at the environmental fate of 200 of the most commonly used drugs.