Top five things you need to know about nitrate pollution in our water

Thousands of Minnesotans in southeastern Minnesota and beyond can’t trust the water from their kitchen sink because nitrate levels in public and private wells exceed the federal human health standard. MCEA is committed to pushing our local, state, and federal authorities to make the changes necessary to ensure all Minnesotans have drinking water that’s safe from nitrate pollution. We have the expertise and experience to be successful, and we won’t stop until every Minnesotan has water that is safe to drink.

Keep reading to learn more about this pressing issue. 

1. Industrial agriculture is the main source of the problem

The biggest contributor to nitrate pollution in southeast Minnesota is industrial agriculture – specifically excessive nitrogen from commercial fertilizer and animal manure applied to cropland. Nitrogen is a nutrient that comes in many different forms and exists in the atmosphere, in our soils, and in the water. When applied at reasonable rates, it’s critical for plant growth. However, too much of it is dangerous for public health, as well as the health of fish and other aquatic life. Excess nitrate levels in both commercial fertilizer and animal manure leach through the soil into our groundwater. In areas of the state that are heavily drain-tiled, like the Minnesota River Valley, agricultural drain tile carries that nitrate to streams and rivers. In fact, nitrogen from cropland groundwater and agricultural drain tile accounts for more than 70% of the nitrogen found in Minnesota’s waters. 

Animal feedlots are also a big part of the problem. Today, there are approximately 24,000 feedlots in Minnesota that generate about 50 million tons of manure a year. Large Concentrated Animal Feeding Operations (CAFOs) – feedlots with 1,000 or more animal units – are just 4 percent of feeding operations in Minnesota, but they produce nearly a third of the manure. And the number of CAFOs in Minnesota continues to rise: in fact it has tripled since 1991. 

2. Minnesota’s Karst region is the geological canary in the coal mine for a wide-spread issue

Nitrate-contaminated drinking water has reached crisis proportions in the karst region of southeast Minnesota, where the thin layer of topsoil and “swiss-cheese-like” porous limestone bedrock allows nutrient runoff from manure and fertilizer to quickly infiltrate groundwater supplies. Nitrate levels in the karst routinely exceed federal and state drinking water standards, putting the health of approximately 380,000 area residents at risk – private well owners are particularly impacted. 

The sensitivity of the region to groundwater pollution has been well documented. From 2016 to today, the Minnesota Department of Agriculture has tested private wells for nitrate contamination. Of the over 32,000 wells tested statewide, about 9 percent exceeded the federal human health limit of 10mg/L. In southeast Minnesota, about 16 percent exceeded the health risk limit. In some townships, such as Utica and Fremont, the number was 40 percent. 

Public water supplies in the region have exceeded the health risk limit as well. Most recently, Utica in Winona County has had to increase water rates to help pay for a $2 million project to dig a deeper well to circumvent the problem.

3. Nitrates impact human health at very low levels

One of the illnesses nitrate ingestion can cause is commonly known as blue baby syndrome, which prevents the hemoglobin in a newborn’s blood from carrying enough oxygen to the baby’s extremities, like hands and feet, turning them blue. It can also stop babies from breathing. Established in 1962, the current federal safe drinking water limit for nitrate - 10 milligrams per liter - was set to address the increase in cases of the syndrome, called methemoglobinemia.

But studies have linked even lower levels of nitrate contamination in water to cancer as well as birth defects and pregnancy complications. Levels as low as 5 milligrams per liter of water have been shown to lead to an increased risk of thyroid cancer, ovarian cancer, and bladder cancer. 

4. There are solutions

There are two primary types of solutions to the problem that could both support rural communities and address the persistent contamination of water supplies from agricultural practices. The first involves providing immediate public health support where needed. This would include education and outreach to inform residents of the health risks, hazard assessments of the most at-risk wells, free access to laboratory analysis of water samples, and free alternative water sources for people whose water is above the federal health limit.

The second, and equally critical type of solutions, involve prevention. This includes potential remedies under state law like more protective feedlot permits for the the karst region, a grant program to increase manure storage capacity and incentivize alternative manure management practices for small and mid-size feedlots, and a more widespread adoption of best management practices like cover crops.

On April 24th, MCEA and a group of ten local, state, and national environmental groups filed a petition to the U.S. Environmental Protection Agency (EPA) asking for emergency action to address the ongoing drinking water crisis in southeastern Minnesota. If you haven’t already, add your name to our petition today so decision makers feel the pressure to act. 

5. Residents in the karst region have been left to advocate for themselves 

Watch this video MCEA created to learn more about community members’ fight for clean water in the karst region.