Drug residue in water stirs concerns

Several 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.

Utilities insist their water is safe. And indeed, the concentrations of the pharmaceuticals are tiny, measured in quantities of parts per billion or trillion, far below the levels of a medical dose.

But the presence of so many prescription drugs, and of over-the-counter medicines such as acetaminophen and ibuprofen, in so much of the nation's drinking water is heightening worries among scientists of long-term consequences to human health.

In the course of a five-month inquiry, the AP discovered that drugs have been detected in the drinking water supplies of 24 major metropolitan areas, from Las Vegas and Southern California to New Jersey.

How do the drugs get into the water?

People take pills. Their bodies absorb some of the medication, but the rest of it 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.

And while researchers do not yet understand the exact risks from decades of persistent exposure to random combinations of low levels of pharmaceuticals, recent studies 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.

The federal government does not require any testing and has not set safety limits for drugs in water. Of the 62 major water providers contacted, the drinking water for only 28 was tested.

Some providers screen only for one or two pharmaceuticals, leaving open the possibility that others are present.

And rural consumers who draw water from their own wells are not in the clear either, experts say.

Even users of bottled water and home filtration systems do not necessarily avoid exposure. Bottlers, some of which simply repackage tap water, do not typically treat or test for pharmaceuticals, according to the industry's main trade group. The same goes for the makers of home filtration systems.

Contamination is not confined to the United States. More than 100 different pharmaceuticals have been detected in lakes, rivers, reservoirs and streams throughout the world. Studies have detected pharmaceuticals in waters throughout Asia, Australia, Canada and Europe.

"People think that if they take a medication, their body absorbs it and it disappears, but of course that's not the case," said EPA scientist Christian Daughton, one of the first to draw attention to the issue of pharmaceuticals in water supplies.

Recent laboratory research has found that small amounts of medication have affected human embryonic kidney cells, human blood cells and human breast cancer cells.

Also, pharmaceuticals in waterways are damaging wildlife across the nation and around the globe, research shows. Notably, male fish are creating egg yolk proteins, a process usually restricted to females.

Pharmaceuticals also are affecting sentinel species at the base of the food chain such as earth worms in the wild and zooplankton in the laboratory, studies show.

Some scientists emphasize that the research is extremely limited, but the documented health problems in wildlife are disconcerting.