Photo: MPCA

By Laura Durenberger-Grunow - Boreal Community Media - December 22, 2025

Last week, the Minnesota Pollution Control Agency (MPCA) announced the launch of two new scientific projects to better understand sulfate levels in the state’s waters. These studies will look at how sulfate occurs across Minnesota and review the latest research on its specific impacts on wild rice, or manoomin, in Ojibwe. Sulfate is a mineral naturally found in surface waters everywhere in Minnesota, though levels are typically much higher in the southern part of the state than in the north.

Wild rice is a native plant that holds significance in this region and beyond. It is a vital cultural and spiritual resource for the Dakota and Ojibwe Tribal Nations. According to the MPCA, the plant is a "cultural resource to many" and serves as an "important economic resource to those who harvest and market it." 

Wild rice is highly sensitive to its environment and thrives best in low-sulfate waters. As a result, the state adopted a 10 mg/L sulfate standard in 1973. However, since that rule is now decades old, various groups have called for an updated analysis. 

The first project will document the variation in sulfate levels across Minnesota. Using statistical tools, scientists will filter out sulfate from human sources, such as industrial sites or runoff, to determine the amount that would exist on its own. The MPCA says this will lead to more accurate maps of naturally occurring levels across Minnesota.

In the second project, the organization will work with independent researchers to analyze peer-reviewed science on how sulfate affects wild rice ecosystems. While current studies already show that sulfate can turn into sulfide, which is toxic to the plant, the MPCA wants to integrate the most up-to-date data into its policies.

Both studies are expected to be finished by late 2026, according to the MPCA. Until then, the existing 10 mg/L sulfate standard remains in effect and will be enforced under the Clean Water Act. The U.S. Environmental Protection Agency (EPA) will have the final say on any permits issued during this time.