Stephanie Hemphill, reporting for MinnPost:
“Minnesota’s current standard to protect the iconic grain is ten milligrams of sulfate per liter. But industry has attacked that standard as unscientific. Mines, wastewater treatment plants, and other industries dispose of sulfate in rivers, and native groups have long complained the stands they rely on have been declining.
The research shows that bacteria convert sulfate into sulfide in the sediments in which wild rice typically grows. Researchers found strong correlations between the amount of sulfide in the porewater (water that flows in and around the sediments) and the amount of sulfate in surface water.
The agency concluded that the range at which sulfide limits the plants’ ability to grow corresponds to a range of sulfate in the surface water of 4 to 16 milligrams per liter – neatly bracketing the current standard.”
