Then what are they?

I’d be a bit concerned about drinking tap water as well, particularly if yours comes from a surface source.  I track a lot of these type of articles and the frequency of new instances of effects on fish and amphibians is stunning:

http://www.denverpost.com/Stories/0,1413,36~53~2442899,00.html

http://www.medicalnewstoday.com/medicalnews.php?newsid=13688

Thus far no one has come out with anything that looks at human effects, but I imagine studies are being done.