New warnings of water contamination from farm pollution in Wisconsin
While all eyes have been on Iowa this summer, where levels of harmful nitrate contamination of water supplies spiked well above federal safety standards, nitrate pollution has also been persistently plaguing water sources in other farm states as well.
On Thursday, Wisconsin environmental advocates issued a lengthy report detailing what the groups said is that state’s own “growing public health crisis from nitrate contamination in drinking water.”
Similar to the situation in Iowa, nitrate contamination stemming from agricultural practices is putting public health at risk and raising costs for water treatment efforts, according to the research released by the Alliance for Great Lakes nonprofit group and Clean Wisconsin advocacy organization.
When pregnant women are exposed to nitrates in drinking water, it raises the risks of problematic birth outcomes, including low birth weights and pre-term birth. Babies can suffer severe health problems when consuming nitrates in drinking water, and a growing body of literature indicates potential associations that include an increased risk of cancer. Iowa has the second-highest rate of cancer in the nation, and many attribute the rising rates there to agricultural pollution.
The new report cites data showing that many Wisconsin streams have shown elevated levels of nitrate at times that exceed 30 milligrams per liter (mg/l), three times the benchmark for allowable level of 10 mg/l set by the Environmental Protection Agency (EPA). The report notes that the 10 mg/l level was set decades ago, and new science indicates health risks occur at levels lower than the standard.
More than 90% of nitrate pollution of groundwater in the state is linked to agricultural sources – generated by farmer application of nitrogen-containing fertilizers, including manure, commercial fertilizer, and biosolids to farm fields, according to the Wisconsin report.
Farmers often apply an excess of nitrogen to their fields, researchers have found, adding to groundwater and surface water contamination. In Wisconsin, this excess totaled over 16 million pounds in 2022 alone, the report estimates.
“Nitrates are Wisconsin’s most widespread drinking water contaminant, with health risks even at low levels. The costs of treating our drinking water will only continue to rise, so we need to tackle this challenge at its source,” Sara Walling, Clean Wisconsin Water & Agriculture Program Director, said in a statement accompanying the release of the report.
“Agriculture needs to have a seat at the table if we are going to identify and implement workable, effective and widespread solutions to protect families, safeguard water, and sustain our state’s farming future. This report is a call to start those conversations in earnest,” Walling said.
The report calls for increased enforcement of polluters, updated state water standards, expansion of a program that reimburses costs for private wells and monitoring groundwater, as well as costs borne by public water systems.
The report states that as of 2024, estimates show municipal utility systems have spent over $40 million to try to remediate nitrate contamination and that the public water systems are increasing rates to consumers to pay for the remediation.
The report accuses state lawmakers of hindering efforts to protect public and environmental health from agricultural pollution.
“This report is a call to action for comprehensive changes in policy and practices that are necessary in Wisconsin – as well as other areas throughout the Great Lakes Basin – to protect our drinking water and stop the pollution at its source,” Angela Blatt, senior agricultural policy manager for the Alliance for the Great Lakes, said in a statement.
(Featured image of corn field in Wisconsin, provided in Nitrates on Tap report.)
