Two veteran U.S. senators said Monday they plan to hold hearings in response to an Associated Press investigation into the presence of trace amounts of pharmaceuticals in the drinking water supplies of at least 41 million Americans.

Also, U.S. Rep. Allyson Schwartz, D-Pa., has asked the EPA to establish a national task force to investigate the issue and make recommendations to Congress on any legislative actions needed.

Sen. Barbara Boxer, who heads the Senate Environment and Public Works Committee, and Sen. Frank Lautenberg, chairman of the Transportation, Safety, Infrastructure Security and Water Quality Subcommittee, said the oversight hearings would likely be held in April.

Boxer, D-Calif., said she was "alarmed at the news" that pharmaceuticals are turning up in the nation's drinking water, while Lautenberg, a New Jersey Democrat who said he was "deeply concerned" by the AP findings, both represent states where pharmaceuticals had been detected in drinking water supplies, but not disclosed to the public.

"I call on the EPA to take whatever steps are necessary to keep our communities safe," said Boxer in a statement.

Added Lautenberg, whose subcommittee has jurisdiction over drinking water issues: "Our families deserve water that is clean and safe. Our hearing will examine these problems and help ensure the EPA and Congress take the steps necessary to protect our residents and clean up our water supply."

EPA spokesman Timothy Lyons said the agency is "committed to keeping the nation's water supply clean, safe and the best in the world. We encourage all Americans to be responsible when disposing of prescription drugs."

The Lautenberg-Boxer announcement came just 24 hours after the AP's release of the first installment of its three-part series, titled PharmaWater.

The five-month-long inquiry by the AP National Investigative Team found that while water is screened for drugs by some suppliers, they usually don't tell their customers that they have found medication in it, including antibiotics, anti-convulsants, mood stabilizers and sex hormones.

The series shows how drugs - mostly the residue of medications taken by people, excreted and flushed down the toilet - have gotten into the water supplies of at least 24 major metropolitan areas, from Southern California to northern New Jersey. The stories also detail the growing concerns among scientists that this pollution has adversely affected wildlife, and may threaten human health.

In a letter to EPA administrator Stephen Johnson, Schwartz said, "Like many Pennsylvanians, I was especially taken aback by the finding of 56 different pharmaceuticals discovered in the drinking water for the City of Philadelphia.. . . The Associated Press report raises serious questions about the safety and security of America's water system."