Carl Zauche of Hiawatha, Iowa heard our show about traces of pharmaceuticals being discovered in rivers and groundwater. Carl, if you flush them down the toilet or wash them down the drain, they'll eventually end up somewhere in Earth's water. If you throw your expired drugs into the trashcan, they'll probably end up in a landfill where they can leach out. The fact is, there's no definitive answer at this time. Another possibility is to dispose of pharmaceuticals with your other hazardous substances.
Many communities have a household waste drop program.
We're Block and Byrd for Earth and Sky.