Minnesotans are intelligent, compassionate, brave people. With a bit more information about our state's sulfate standard, they will see beyond the mining industry's bluster, as in a recent commentary ("It's time for the MPCA to raise the state's sulfate standard," Dec. 14). Minnesotans will realize that it's time for the Minnesota Pollution Control Agency to uphold our existing limit on sulfate pollution as reasonable and necessary to protect wild rice and the water quality of lakes and streams we all hold dear.

Let's start with the science. Even in the 1940s, when field research on thousands of Minnesota lakes found that wild rice beds thrived only when the water had 10 milligrams or less of sulfate, scientists suspected that the chemistry affecting wild rice was complicated. Recent groundbreaking studies by University of Minnesota researchers supported by $1.5 million of taxpayer funds have proved how sulfate harms wild rice.

Sulfate becomes toxic to wild rice when it turns into sulfide in the mucky bottom of lakes and streams where wild rice grows. Sulfide can harm nearly every part of the wild-rice life cycle — from stunting seedlings to reducing viable seeds for next year's plants. Sulfide is toxic to wild rice in very small amounts. Minnesota research shows that when sulfide in the rooting area of wild rice is only 0.165 milligrams per liter — less than 2 percent of our 10-milligrams-per-liter limit on sulfate in water — virtually no wild rice will survive.

After Minnesota's recent wild rice studies were completed (but before mining industry pressure went into overdrive), the MPCA concluded: "The 10 [milligrams per liter] sulfate standard is needed and reasonable to protect wild rice production from sulfate-driven sulfide toxicity."

If an industry lobbyist tries to tell you that Minnesota's wild rice sulfate limit isn't needed because wild rice can survive a couple of weeks in a test tube with lots of sulfate in it, tell them you know better.

Next, let's look to what we value in Minnesota. Many of us care that wild rice is Minnesota's state grain and that it is vital to Ojibwe tribes as well as to the ecosystem that supports fish and wildlife.

In addition, as a result of the same chemistry that harms wild rice, sulfate from mining and other industrial pollution increases the release of phosphates, turning clear lakes into eutrophic green, slimy waters. Sulfate pollution also increases methylation of mercury, allowing mercury to concentrate in the food chain up to a million times and contaminate the fish we eat. Although we are all at risk, the developing brains of unborn children are most vulnerable to mercury toxicity. In Minnesota's Lake Superior region, 1 out of 10 infants is already born with mercury in the blood exceeding safe levels.

Finally, along with brains to understand why the sulfate standard is needed and heart to care, we need to help the MPCA find the courage to stand up to the mining industry and defend the existing sulfate limit of 10 milligrams per liter. Pollution already has decimated wild rice, degraded some northern Minnesota streams and lakes so they can't support fish, and harmed Minnesota's children. It is bad policy and just plain wrong to let the mining industry decide what limits should be placed on sulfate and other pollutants.

It is time to pull away the curtain of corporate self-interest and protect Minnesota's wild rice, fish, lakes, streams and the developing brains of our next generation.

Paula Goodman Maccabee is advocacy director and counsel for the nonprofit group WaterLegacy.