ST. PAUL — Minnesota regulators have released proposed rule changes meant to protect wild rice from sulfate pollution.

The Minnesota Pollution Control Agency outlined the proposal Monday. MPCA Commissioner John Linc Stine says the agency believes the proposed changes “are an innovative and precise approach to protecting wild rice” while allowing for flexibility in permitting for facilities that discharge into wild rice waters.

Native Americans consider wild rice a food source both sacred and crucial to their cultural identity.

The existing rule limits sulfate discharges into wild rice waters to 10 milligrams per liter. But based on new research, the agency is proposing limiting sulfide in the sediment in which wild rice grows to 120 micrograms per liter.

American Indian tribes and environmentalists say the proposal is inadequate.

Public hearings begin in October.