WASHINGTON, April 25 (TNSxrep) -- The Environmental Working Group issued the following research: * * * Drinking water of almost 1 in 5 Americans contains nitrates linked to cancer and birth defects Overview * Nitrate pollution of drinking water is mainly caused by fertilizer and manure from agriculture. * Even with nitrate's known health harms, about one-fifth of the U.S. population drinks water contaminated with elevated nitrate levels. * Climate change is making the problem worse and fed more PR