You might be surprised what might be in our rivers. I haven't studied the details pro or con, but there is concern about estrogen from birth control making it's way past water treatment plants and back into rivers.
The International Institute for Sustainable Development-Experimental Lakes Area (IISD-ELA) and the University of New Brunswick today release the findings of a study that show that the birth control pill has unexpected effects on aquatic ecosystems.
www.iisd.org