Sheila Wegman
One of Minnesota’s biggest sources of climate pollution and one of our biggest sources of water pollution comes from the same source: agriculture.
Nitrates from fertilizer and feedlots pollute surface and groundwater in Minnesota and create nitrous oxide, a greenhouse gas 300 times more harmful to the climate than carbon dioxide.
Nitrates are especially dangerous in geologically sensitive areas like Minnesota’s southeast Karst and Central Sands regions, where they infiltrate surface and groundwater. Drinking water in these regions is poisoned with nitrates and linked to colon cancer, bladder cancer, and birth defects. Nitrates also kill fish and cause toxic algal blooms, which hurt fish habitat and make lakes unsafe for swimming.
In 2010, the legislature told the Minnesota Pollution Control Agency (MPCA) to create an enforceable nitrate standard that would protect aquatic life. Fifteen years later, there is still no standard, and the problem keeps getting worse.
Bad News: Poor Management Leaves Contaminated Water Left Untreated
Even though we know that pollution from fertilizer and manure is degrading our drinking water, aquatic life, and climate, stage agencies have failed to take real action.
The Clean Water Act essentially exempts agriculture discharges from federal enforcement (Laitos & Ruckneigle, 2013), and state rules on manure from feedlots and Minnesota’s Groundwater Protection Rule on fertilizer application have enforcement provisions that are rarely used. Minnesota agencies tell us that they prefer to use technical and financial assistance to encourage the farming community to voluntarily prevent nitrate pollution (Minnesota Department of Agriculture, n.d.; G. Schwindt. MPCA, personal communication, October 7, 2024). But that approach is not working.
Although wells in southeast Minnesota have long been known to be contaminated with nitrates, clean-up attempts were so ineffective that in 2023, the Minnesota Center for Environment Advocacy (MCEA) and other parties successfully petitioned the US EPA to require state action. State agencies are now identifying contaminated wells and providing alternate water sources for those affected. With this action plan due to expire, and ever more nitrate pollution being discovered, MCEA is now suing state agencies to force them to better manage nitrate pollution in fields and feedlots.
What More Needs to Be Done?
Several tools can decrease both nitrate water pollution and nitrous oxide emissions.
- Precision fertilization. One technique is to use less fertilizer by increasing fertilizer fees and using precision agriculture, a technique for providing fertilizer exactly as the plant needs. These and other best practices should be mandated. Members of the Sierra Club are meeting with legislative personnel and seeking the introduction of a bill focused on these strategies.
- Treatment of tile drainage. Drain tiles are the pipes buried under farm fields to remove water. They also transport agricultural chemicals. Tiling accounts for 37% of nitrate pollution in Minnesota’s water. We are working on community outreach and legislation to mandate the treatment of tile drainage in MN.
- Expand water quality monitoring. It is not enough for farmers to claim that they are controlling pollution by using best practices; they should prove it.
- And most importantly, enforce existing laws. We strongly believe that the state should use existing enforcement authority in the MPCA Feedlot Permit program and the Groundwater Protection Rule. Monitoring and enforcement authority should be added to voluntary programs such as the Agricultural Water Quality Certification Program.
The Chapter is a leading organization in the People Not Polluters Campaign, which is seeking to holistically address the problem of agencies not enforcing existing laws, as is exemplified here.
Sheila Wiegman is a lifelong environmentalist, Waters and Wetland Stewards member, former USEPA environmental engineer and now works as a nurse practitioner. She loves walking, lakes, and new challenges.