The study found that the area has some of the highest nitrate and phosphorus pollution in the country. Iowa concentrations were higher than those in the surrounding states. Nitrates and phosphorus contribute to algae blooms that can leave rivers mucky, clog pipes, kill bottom plants and cut the number of fish in a lake. In effect, they kill lakes. Three-fourths of the river samples exceeded the limit suggested by the U.S. Environmental Protection Agency to keep algae from becoming problems.
Health is a concern, too.
The algae blooms can produce toxins capable of causing skin irritations and intestinal trouble. Iowa water utilities sometimes have to mix water from different sources to keep the nitrates at levels the EPA considers safe. A recent study by the University of Iowa found that women faced a higher risk of bladder cancer even if, for more than a decade, they drank water containing even smaller amounts of nitrate than the EPA safe levels. Des Moines Water Works operates the world's largest nitrate-removal system when summertime levels jump beyond the federal limit. The report raised the prospect of more health trouble.