vast array of pharmaceuticals ? including antibiotics, anti-convulsants, mood stabilizers and sex hormones ? have been found in the drinking water supplies of at least 41 million Americans, an Associated Press investigation shows.
The concentrations of the pharmaceuticals are tiny, measured in quantities of parts per billion or trillion, far below the levels of a medical dose. Utilities insist that their water is safe.
But the presence of so many prescription drugs ? and over-the-counter medicines like acetaminophen and ibuprofen ? in so much drinking water is heightening concerns among scientists about the possible long-term consequences to human health.
During a five-month inquiry, the AP discovered that drugs have been detected in the drinking water supplies of 24 major metropolitan areas ? from southern California to northern New Jersey and from Detroit to Louisville, Ky.
Austin was one of three metropolitan areas reporting that no such drugs had been detected in its water.
Water providers rarely disclose results of pharmaceutical screenings unless pressed to do so, the AP found.
How do the drugs get into the water?
People take pills. Their bodies absorb some of the medication, but the rest passes through and is flushed down the toilet. The wastewater is treated before it is discharged into reservoirs, rivers or lakes. Then, some of the water is cleansed again at drinking water treatment plants and piped to consumers. But most treatments do not remove all drug residue.
Waste from animals that had been given veterinary drugs also plays a role.
Researchers do not yet understand what exact risks come with decades of persistent exposure to random combinations of low levels of pharmaceuticals. But recent studies, which have gone virtually unnoticed by the public, have found alarming effects on human cells and wildlife.
"We recognize it is a growing concern, and we're taking it very seriously," said Benjamin Grumbles, assistant administrator for water at the U.S. Environmental Protection Agency.
Members of the AP National Investigative Team reviewed hundreds of scientific reports, analyzed federal drinking water databases, visited environmental study sites and treatment plants, and interviewed more than 230 officials, academics and scientists. They also surveyed the nation's 50 largest cities and a dozen other major water providers, as well as smaller community water providers in all 50 states.
Here are some of the key test results obtained by the AP:
? Officials in Philadelphia said testing discovered 56 pharmaceuticals or byproducts in treated drinking water, including medicines for pain, infection, high cholesterol, asthma, epilepsy, mental illness and heart problems.
? Epilepsy and anxiety medications were detected in a portion of the treated drinking water for 18.5 million people in Southern California.
? Researchers at the U.S. Geological Survey analyzed a Passaic Valley Water Commission drinking water treatment plant, which serves 850,000 people in northern New Jersey, and found a metabolized angina medicine and the mood-stabilizing carbamazepine in drinking water.
? A sex hormone was detected in San Francisco's drinking water.
? The drinking water for Washington and surrounding areas tested positive for six pharmaceuticals.
