The state of California has a warning for its 36 million residents: Do not flush pharmaceuticals down the toilet or drain, or they may end up in a river near you.
Or, it turns out, even in the drinking water.
Researchers have found evidence that even extremely diluted concentrations of pharmaceutical residues harm fish, frogs and other aquatic species in the wild. Related research reports that human cells fail to grow normally in the lab when exposed to trace concentrations of certain drugs.