By Roberta Attanasio The problem of contaminated tap water in the U.S. goes well beyond Flint—and also beyond lead. There are many more toxic chemicals in our drinking water that we like to believe. Communities in New York, New Hampshire and Vermont recently found elevated levels of PFOA, a suspected carcinogen, in their water supplies. PFOA, or perfluorooctanoic acid, is a synthetic perfluoroalkyl chemical used to manufacture nonstick pan coatings and water-resistant clothing. And, even more recent is the finding that water discharged from Burlington’s wastewater treatment plant into Lake Champlain—the source of drinking water for tens of thousands of people in the Burlington area—contains concentrations of pharmaceuticals high enough to reflect…