Gov. Mark Dayton has vetoed a bill that he says would have unlawfully undermined Minnesota's water quality standard for protecting wild rice.

Dayton, who vetoed a similar bill earlier, says the revised version represented "some progress," but not enough to overcome its shortcomings.

He says the bill would have given a work group authority to take over the Minnesota Pollution Control Agency's responsibilities under state and federal law for protecting wild rice. He says that would have violated federal law and offended Native American tribes that depend on wild rice.

Instead, Dayton announced a task force that will review the science and make recommendations for how best to protect wild rice.

A largely unenforced 1973 state law limits sulfate discharges into wild rice waters to 10 milligrams per liter.