IOWA CITY — More than 6000 Iowans die from cancer every year and the state leads the nation in the number of new cases. Now researchers are investigating some unexplored sources. Iowa is among the nation’s leaders in lung, breast, colorectal and skin cancer and the number of new cases is falling more slowly than nearly every other state.
University of Iowa Professor Peter Thorne says the state’s cancer registry is trying to find answers but often doesn’t take into account the millions of pounds of manure that run into groundwater near corporate animal confinements. “Because we do have private wells that exceed safe levels for nitrate, but we also have public drinking water supplies where the nitrate level is a challenge, particularly in sometimes a year when there’s runoff from farm fields of fertilizer and animal manure.”
Cancer experts say Iowans are also exposed to known carcinogens in the air they breathe, often polluted by pesticides and other chemicals used by corporate ag producers. Water treatment plants will often remove chemicals to meet the legal standards but still leave toxins at dangerously high levels and Thorne says Iowans exposed. “If you’re exposed at levels below 10 milligrams per liter, there’s still an elevated risk of cancer, the stomach, colorectal cancer, thyroid, bladder cancer, associated with nitrates.”
Ammonia, which is present in natural and synthetic fertilizers, is converted by soil bacteria into highly water-soluble nitrate, which finds its way into drinking water.
