Via Wired, it seems that bottled water has some contaminant issues (like that whole scare about polycarbonate water bottles). I still think that leachates are not so great a concern as people think, but most things that will get people to stop drinking bottled water are good ideas in my book.
The study referenced used snails to measure the effects of sex hormone analogues (probably pthalates) that are used as plasticizers in all kinds of things these days. Snails grown in bottled water tended to have a lot more little snails. That is an indicator that there might be some hormone analogues coming out of the plastic.
I doubt the effects on humans will be so easily determined.