Even drinking tap water may cause cancer, according to a University of Iowa study. The study of 22-thousand women in 400 Iowa communities analyzed long-term exposure to nitrates in drinking water from municipal supplies and private wells. The study’s lead author, Dr. Pete Weyer, is associate director of the U-of-I’s Center for Health Effects of Environmental Contamination. Women who drank municipal water over at least ten years had a higher risk of bladder cancer. Dr. Weyer says he’s not trying to frighten anyone, but wants to make them better informed. Dr. Weyer says farmers and homeowners should consider ways to cut nitrate levels in the groundwater, like reducing the amount of fertilizers or nitrogen used on their crops or lawns.