Clean Water Action said more aggressive testing, pollution prevention and upgraded treatment technologies are needed to assess and reduce a growing array of prescription and over-the-counter drugs flowing through the nation's water supply.

The environmental group was reacting to an Associated Press report yesterday that trace amounts of drugs, including antibiotics, anti-convulsants, mood stabilizers, heart medicines and sex hormones, have been found in the drinking water supplies of at least 41 million Americans.

Despite scientists' concerns about the effect of those trace drugs on human health, including reproductive functions and cancer, the Bush administration's 2009 budget proposal cuts $10 million from the water monitoring and research program.

"Pennsylvania has been a leader in studying pharmaceutical levels in rivers and streams across the state, but the federal government needs to do its share," said Myron Arnowitt, state director of Clean Water Action.

"In addition, both the state and federal government need to support not only monitoring, but also research into preventing this pollution and into the best possible treatment technologies for drinking water and sewage systems."

The pharmaceuticals get into the water supply when they pass through humans and farm animals that have ingested them, and when old or unused prescriptions are dumped into toilets.

The Pennsylvania Department of Environmental Protection and the U.S. Geological Survey's National Water Quality Assessment program have found small amounts of the pharmaceutical chemicals in many of the state's surface waters. Early studies show they are harming fish, reptiles and other aquatic species.

In Philadelphia, testing has discovered 56 pharmaceuticals or by-products in treated drinking water and 63 in untreated water in the city's watersheds.

Although the U.S. Environmental Protection Agency recognizes that pharmaceutical chemicals in the water supply are a growing concern, water suppliers and sewage treatment facilities are not required to test or monitor for such substances. Like those in most of the nation's largest cities, no Pittsburgh-area water suppliers conduct those tests.

"We haven't done any testing of those things at all and there's no EPA methods or lab to send such tests to," said Stanley States, water quality manager for the Pittsburgh Water and Sewer Authority, which draws its water from the Allegheny River. "We're really looking to the EPA for the lead on this because it's an issue of national concern."

Dr. States said the technology to test for the pharmaceutical contaminants, which can occur in very small concentrations is relatively new.

"Even if you could measure it, to link these things to human health effects will be very difficult. It could take awhile," he said.

Sharon A. Bruno, director of administration and spokeswoman for the West View Water Authority, which draws its water from the Ohio River, said the authority has no concerns about pharmaceuticals in the water supply and does all the tests required by law.

Art Tamilia, director of environmental compliance for the Allegheny County Sanitary Authority, said the treatment facility along the Ohio River in Woods Run is not looking for pharmaceuticals in its intake stream or treating its discharges to remove them.

"Our treatment is driven by regulations which are driven by environmental impacts and human health," said Mr. Tamilia, who added that any additional treatment to remove such drug residues would be expensive.

He said more research is needed to determine the impact of the pharmaceuticals and the extent to which they are harmful to human health. He said the best and least expensive method of control would be to educate the public not to flush unused drugs down the toilet and instead to throw them away in the trash.

Dr. States said home carbon water filters may provide effective controls because the pharmaceuticals are carbon-based chemicals. Treatment systems using reverse osmosis would also be effective but are expensive and complicated for home use, and waste a lot of water for municipal use.