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State gets data on sulfates and wild rice; will consider changing standard

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Two years worth of data on sulfates and wild rice have landed in the offices of state officials. Now they'll consider whether Minnesota should change its sulfate standard – a decision that has implications for the mining industry.

The Duluth News Tribune reports the $1.5 million dollar project involved field and lab work by scientists at the University of Minnesota campuses in Duluth and the Twin Cities. One of the lead scientists tells the newspaper their work corroborated research from the 1940s that found rice does not grow as well in water high in sulfates. Now it it will be up to the state to decide how much is too much.

Sulfates, the article explains, are ions that come from decaying plants and animals but are also released in mining discharges. The News Tribune says several existing taconite operations do not meet today's standard limiting sulfates to 10 milligrams per liter in wild rice waters. With new copper-nickel mines proposed for northeastern Minnesota, regulators are under pressure to relax the standard. But critics say more sulfates would hurt rice beds and cause other environmental harm.

Minnesota Public Radio says the existing standard dates to 1973 but was largely unenforced until 2010.

The Pollution Control Agency tells the Associated Press its recommendation on whether to change the standard will come by the end of next month. That will open a rulemaking process that will involve public input and will be overseen by the Environmental Protection Agency, the News Tribune says.

The PCA has a page that provides a summary of the U of M's study along with next steps in the process.

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