Minuscule amounts of medicines in rivers and streams can alter the biology and behavior of fish and other marine animals.

The findings, published online Thursday in the journal Science, add to the mounting evidence that minuscule amounts of pharmaceuticals are environmental contaminants can alter the biology and behavior of fish and other marine animals. ‘‘I think people are starting to understand that pharmaceuticals are environmental contaminants,’’ said Dana Kolpin, a researcher for the U.S. Geological Survey who is familiar with the study. Read more