Fertilizer runoff threatens Midwest water
Forget the Gulf of Mexico or Chesapeake Bay, waters that conservation and environmental groups say are threatened by agricultural runoff. Thursday the Environmental Working Group released a report that documents threats to municipal water systems and private wells in the Midwest due to nitrogen and phosphorous fertilizer.
The report, “Troubled Waters: Farm pollution threatens drinking water,” is a thorough survey of work by the U.S. Geological Survey and other government agencies that monitor water quality. It focuses mainly on the data compiled from surface and ground water testing in Iowa, Minnesota, Wisconsin and Illinois, and Missouri.
“Water that runs off poorly managed fields that have been treated with chemical fertilizers and manure is loaded with nitrogen and phosphorus,” the EWG said when it released the report today. “These two potent pollutants set off a cascade of harmful consequences, threatening the drinking water used by millions of Americans.”
Some of the report’s findings will be familiar to Midwesterners in farm country, who likely are already aware that nitrate levels in drinking water above 10 parts per million can kill infants by causing a blood disorder known as blue baby syndrome (methemoglobinemia).
And some of the group’s brief suggestions for policy changes won’t surprise, either. Like many organizations, EWG in “Troubled Waters” calls for the elimination of direct payments in the next farm bill. And it’s among many conservation groups that want conservation compliance tied to crop insurance eligibility, a farm bill requirement that ended in 1996.
But the report cites new evidence of health risks, including a report released in February of this year by the National Cancer Institute that shows a significant tie between exposure to nitrates in drinking water and subclinical hypothyroidism in women. (Hypothyroidism is a condition in which the thyroid gland doesn’t’ produce enough thyroid hormone, which can lead to fatigue and more serious medical conditions.) Studies published in 2010 and 2011 also show a link between nitrate intake and thyroid cancer. Nitrate in drinking water competes with iodine uptake into the thyroid.
Thyroid effects may be a serious public health issue.
“That’s what scientists are increasingly concerned about,” said Olga V. Naidenko, a Ph.D. immunologist on the EWG staff who wrote much of the report.
Some municipal water treatment systems in the Midwest remove nitrates from drinking water, but Naidenko told Agriculture.com that farmers and rural residents who rely on shallow wells for drinking water are at higher risk.
“Even drilling deeper wells is not really a solution because the nitrates are going to get there,” she said.
Phosphorous runoff into streams is a cause of cyanobacteria blooms, which create toxins that can kill livestock or pets. The Cyanotoxins from water contaminated by these algal blooms can be removed, but at a high cost, ranging from $500,000 to $5.6 million in annual operating cost for a city of 100,000, according to a Water Research Foundation project. The capital costs to install the treatment ranges from $4.4 million to $56.6 million, depending on the method.