Boston (AP)  -- Beacon Hill lawmakers are hearing testimony on steps the state is taking to protect its drinking water supply from pharmaceuticals.

State Department of Environmental Protection Commissioner Laurie Burt told a special legislative committee Tuesday that the state is conducting studies to try to determine the presence of pharmaceuticals in the water and what health risk they may pose.

She also says the state is trying to prevent drugs from entering the water supply by encouraging people to discard unused prescriptions in the trash rather than by flushing them down the toilet.

Burt says more federal oversight is needed.

The hearing comes on the heels of an Associated Press investigation that discovered a vast array of pharmaceuticals in the drinking water supplies of at least 41 million Americans.