There are traces of sedatives in New York City’s water. Ibuprofen and naproxen in Washington, D.C. Anti-epileptic and anti-anxiety drugs in southern California.

A 2,550 word article from The Associated Press is drawing attention to the widespread problem of trace amounts of pharmaceutical chemicals turning up in the drinking water supply of millions of Americans, but no one seems to know how to react. The report itself culminated with a doctor offering a tried-and-true deduction for the Ages: “That can’t be good.”

But how bad is it, exactly? The answers range in degrees of confidence and alarm, though no one was ready to predict imminent doom.

”We recognize it is a growing concern and we’re taking it very seriously,” said Benjamin H. Grumbles, the Environmental Protection Agency’s water chief. But the government has not established any safety limits for pharmaceutical drugs in drinking water, as it has for many other chemicals; the agency is just learning how to detect low concentrations of drugs in water, let alone assess the risk posed by them.

The American Water Works Association, a trade group representing thousands of water utilities, seemed to suggest that the problem is the testing data, not the water. A California water official warned The A.P. before it published the article that that the public “doesn’t know how to interpret the information” from the tests.

Tom Curtis, the deputy executive director of the association, explained. “Today’s advanced technology has allowed scientists to detect more substances — at lower levels — than ever before,” he said. He called for calm, saying there was no research demonstrating “an impact on human health” from the detected levels of drugs in public water supplies.

So why has this burdensome fact of life been dropped on the shoulders on Americans? The lack of scientific proof of a threat does not rule one out, of course. Little study has been devoted to the long-term effects of low-concentration exposure on humans. But as the A.P. relates, research on the effects on wildlife has yielded some scary examples: Pharmaceuticals in river and lake water are being blamed for “feminized” male fish and other changes observed in earthworms and zooplankton.

So how are all these drugs getting in the water in the first place? Some fraction of every dose a person takes passes through unmetabolized and is evacuated by the body and flushed into sewage systems. Sewage treatment plants are meant to remove the more familiar kinds of pollutants, and typically do not remove pharmaceuticals from waste water as it is cleaned up and released back into the environment, eventually to find its way into other water supply systems. In some places, treated sewage water is reused directly for drinking water after several filtration processes to make it safe, although none of the systems in wide use effectively remove pharmaceuticals.

That Brita filter in your kitchen is not likely to do the trick, either. As for bottled water, it, too, may come from a tap, rather than some remote mountain spring. And the trade group representing bottled-water sellers told The A.P. that they aren’t testing for the presence of trace drugs anyway.

RELATED: Last April, Cornelia Dean covered drugs in the water in Science Times: Drugs Are in the Water. Does It Matter?