Study of Mine Waste Impacts on Wild Rice Released

Wild rice, photo by Eli Sagor
Wild rice (photo by Eli Sagor)

The Minnesota Pollution Control Agency has published the results of a two-year project looking at the effects of sulfate—a byproduct of both iron and sulfide mining—on wild rice. The research was mandated by the legislature, to inform a possible change in water quality standards for mining companies.

Minnesota adopted a sulfate standard of 10 parts per million in 1973, based on research conducted in the 1940s. The Chamber of Commerce sued the state in 2010 on behalf of the mining industry after enforcement of regulation was increased. The lawsuit was dismissed, and subsequent efforts at the Capitol to change the law also failed. But the challenges did largely lead to the current study.

This week’s release of information does not include final conclusions or a recommendation on whether or not the state should consider changing the standard. The MPCA says over the next two months, it will integrate the reports, analyze the data, review existing data and other information, and the original basis for the standard. This process will help determine whether a change to the standard is warranted.

Last year, one of the scientists said the research so far was correlating with the original study in the 1940s. “We’re sort of confirming Moyle’s original empirical evidence that there is a correlation between sulfate and wild rice, there may be many reasons for that, but we’re having trouble finding sites that are high wild rice and high sulfate,” University of Minnesota researcher Amy Myrbo told Minnesota Public Radio News.

Wild rice is deeply important to the state’s Ojibwe people. It is seen as a gift by their creator, and the reason they settled in what is now Minnesota and Wisconsin after traveling west several centuries ago. It is also the state of Minnesota’s official grain.

According to scientists studying the issue, the sulfates harm wild rice by feeding bacteria which create harmful hydrogen sulfide. John Pastor, a researcher at the University of Minnesota—Duluth who is leading the study, told the Conservation Volunteer magazine last year that he believes sulfides affects root growth and block nutrients from getting into plants.

Sulfates have already been blamed for destroying wild rice downstream of existing mine operations. The Fond du Lac Band of Lake Superior Chippewa have traditionally harvested rice in the St. Louis River and upper Mississippi River watersheds. The band’s water resource policy director, Nancy Schuldt, MPR News, “The poster child would be Sandy and Little Sandy lake, at the toe of the Minntac Tailings basin. A generation ago, band members from Grand Portage for instance, were having rice camps there, and there would be familial gatherings and it was a meeting place. And now there’s no rice to harvest.”

The published reports are available to download on the MPCA’s website.

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