CHICAGO (AP) - The realization that household medicines tossed into the garbage or flushed down the drain pose serious risks to groundwater, has caused government agencies to rethink disposal methods.

On Saturday, Cook County will join Will, Kendall and other counties in providing a safe way for residents to toss out their old prescription drugs. The county will hold its first medicine collection drive at the Metra commuter parking lot in the south suburb of Midlothian.

Dave Walters of the Illinois Environmental Protection Agency says the number of communities that are providing safe ways for residents to dispose of their old prescription drugs is growing every week.

Officials say the medicine that will be collected Saturday will not buried in landfills for fear the chemicals could seep into the water supply. Instead, the drugs will be incinerated.

On the Net: Illinois EPA Pharmaceuticals Disposal Fact Sheet