By Julia Shanahan | June 20th, 2019
The Environmental Working Group released a study outlining a link between the amount of nitrates someone consumes through tap water to a higher risk of cancer. Nitrate pollution in U.S. drinking water potentially caused 12,594 cases of cancer in a year, according to the study.
The study attributed the large amount of nitrates in drinking water to agricultural runoff that contains fertilizer and manure. The EWG estimates it would cost about $1.5 billion a year in medical costs to treat those cases. Of those 12,594 cases, 54-82 percent are colorectal cancer cases. Additionally, the risk for bladder and ovarian cancers are increased in postmenapausal women.
The current federal limit for the amount of nitrates legally allowed in drinking water is 10 parts per million, but as outlined in the study, other serious health risks have been linked to nitrate-polluted water that is only one-tenth under the federal limit. Scientists from the EWG estimate that in order for there to be no adverse health risks, the nitrate level in drinking water should be 0.14 milligrams, which is 70 times lower than the EPA’s legal limit.
In Iowa, nitrate pollution remains a threat to tap water and well water in rural and urban cities across the farm state. The Iowa Department of Public Health tested 1,700 private wells and found 19 percent of them were at or above the legal limit for nitrates. In 2014 and 2015, the average nitrate levels in 45 Iowa public water systems were at least 5 milligrams – enough to increase someone’s risk of cancer.
More recently in 2018, the Des Moines River and combined Cedar-Iowa Rivers produced the nitrate equivalent of 56 million people. The total amount of nitrates in Iowa rivers in 2018 was 626 million pounds, and treated in sewer discharge amounted to 123 million people, or as blogger and IIHR Research Engineer Chris Jones compares to the population of Japan.