For decades, the MPCA has had a water quality standard of less than 10 parts per million for sulfate released into waters where wild rice grows. The standard has rarely been enforced and few studies have been conducted to determine whether or not this standard is appropriate.
The Star Tribune and MPR both report that the expansion of mining in northern Minnesota, which could release sulfate at much higher concentrations, has created a controversy on this issue. As higher levels of sulfate seep into wild rice beds, environmentalists are calling for the MPCA to enforce its standards, while mining and business interests are asking the MPCA to revise the standards. If the standard is enforced, wastewater treatment facilities could be significantly impacted by the high cost of treating this chemical.