Who cares about sulfate and wild rice? Everyone

By John Myers
Duluth, Minnesota (AP) September 2012

In canning jars, cattle troughs and 100 lakes across Minnesota, scientists are working at breakneck speed to unravel the relationship between the state’s iconic wild rice plant and something called sulfate.

As wild rice enthusiasts in canoes harvest this year’s crop across northern Minnesota, researchers are looking to see how much sulfate is too much for wild rice. The results will help determine whether the state should relax its longstanding limit on sulfate for lakes and rivers where rice grows.

The sulfate limit may help plot the future of the state’s mining industry – both for planned expansions of taconite mining and processing and development of one of the world’s largest deposits of copper and nickel, the Duluth News Tribune reported (http://bit.ly/PGMw8f).

Some taconite mining operations, wastewater treatment plants and proposed copper mining operations might not be able to meet the current sulfate limit of 10 parts per million in wild rice waters, experts say.

“Yeah, it’s not a very big deal, is it?” joked John Pastor, University of Minnesota Duluth researcher who is heading the laboratory research of the sulfate study.

Wild rice is the state’s most important wild food crop. Throw in Indian culture – manomin, or wild rice, is a sacred staple for Ojibwe people – add politicians, environmentalists and the Minnesota Chamber of Commerce all watching, and there’s real drama in the outcome.

And, by the way, everyone wants the results a little more than a year from now.

The $1.5 million study – Minnesota’s largest involving wild rice – started slowly last year, expanded this summer and will conclude after the 2013 growing season, when state funding is scheduled to run out. All of the research is getting input from a 32-person “advisory committee” representing taconite companies, business groups, environmentalists, Indian resource agencies and research universities.

“There’s a lot of interest, for sure, but I wouldn’t call it pressure,” said Mark Tomasek, the PCA’s supervisor of water quality standards, who will help decide the new sulfate standard based on the research. “With that interest comes the money to do the research, so that’s the benefit of how this all happened.”

Pastor is looking at wild rice plants in his lab, grown in individual Ball canning jars subjected to varying degrees of sulfate and other tightly controlled substances.

Pastor also has wild rice growing in large plastic cattle tubs outside at the UMD’s experimental farm on Jean Duluth Road north of town. There, he’s able to recreate actual ecosystems and tweak the water chemistry to simulate elevated sulfate levels.

Researchers at the farm will soon be testing wild rice reaction in water with less than 10 parts per million of sulfate, but also with 50, 100, 150 and 300 parts per million, to see what happens.

“We have 105 little lakes here where we can reproduce all sorts of impacts on the rice,” Pastor said.

Meanwhile, University of Minnesota-Twin Cities limno-geologist Amy Myrbo has crews surveying actual lakes and streams across the state, conducting an intensive study of the water and sediment on lakes with wild rice and lakes that might or could have rice at some point.

They hit 50 lakes last summer and hope to get to 100 this summer, picking spots that are likely to be high in sulfate – areas in western and southern Minnesota with naturally higher sulfate levels, and areas near the Iron Range where sulfate levels are increased due to mining, she said.

Crews are taking samples of water squeezed out of the roots and sediment core samples, and measuring nutrients and water chemistry where the rice is growing, or where it might be growing. They use a Hula-Hoop to measure rice density in each location. If no rice is present, crews look for water lilies that grow in very similar conditions.

“We want to characterize what the roots of the rice are seeing,” Myrbo said. “We don’t want to miss anything.”

Mike Robertson, environmental consultant for the Minnesota Chamber, noted his group has paid experts on the advisory committee monitoring and suggesting ideas for the study and that, so far, the project is developing well.

“There’s been a good conversation on the protocols as they start their work,” Robertson noted. “This is all unique. No other state has a sulfate standard for wild rice.”

Pastor already knows a little bit about sulfate and wild rice. He’s been studying wild rice in cattle watering tubs at UMD’s field station on Jean Duluth Road for eight years under a more than $1 million project funded by the National Science Foundation.

That research dealt with Pastor’s career-long expertise on the effects of nutrients on plants. Pastor found that the single biggest factor determining successful wild rice crops is the plant’s ability to get adequate nitrogen. When sulfate is high, it appears that the plants don’t get enough nitrogen, he said.

Experts say it’s nearly certain that sulfate itself is not the issue. It takes a complicated interaction of microbes, or bacteria, to transform sulfate in the water into sulfides in the sediment, namely hydrogen sulfide, which becomes the culprit. In an oxygen-starved environment, the bacteria “breathe” sulfate, and they “exhale” hydrogen sulfide.

“If sulfate is having this negative effect on wild rice, it’s probably because it can be turned into hydrogen sulfide, which can be very toxic to plants,” said Ed Swain, PCA research scientist who is coordinating the mercury sulfate project.

Pastor said he’s already seen that in his work.

“The rice (grown) in high-sulfate water didn’t look like it had been poisoned. It looked like it has been starved,” Pastor added. “What we think is happening is that the sulfides are affecting the root growth so the plant can’t take in nitrogen. That’s the theory. Now we have to go out and see if we’re right.”

In 2008, tribal resource leaders asked Pastor to expand his work and look at sulfate’s impact on wild rice. What he’s found so far is that increased sulfate level in water appears to affect root growth in wild rice plants. Poor roots mean less nitrogen may be getting up into the plant. Earlier this year Pastor was encouraged by the PCA to apply for the state’s own sulfate study.

Scientists also will look at iron’s relationship to sulfate’s conversion to sulfide, the effects of changing pH and how sulfate can reduce copper, iron and zinc available for plants.

“You don’t just throw in sulfate, and the plant dies. It’s a whole ecosystem reaction that happens over years,” Pastor said.

The researchers aren’t sure what they will find as the work continues into 2013, after which the state money runs out.

“Will we have an answer next year? I don’t know,” said Pastor. “Will we know more? I think so. . We should have eliminated some of the possibilities and narrowed it down by then. I do know this is the most complete measure of a plant that I’ve ever done.”

Myrbo said she’s less certain that the research will lead to definitive results after just two or three seasons. Wild rice naturally waxes and wanes on roughly four-year cycles, which Pastor found to be related to the degree of decay from the previous year’s crop.

“I think we need to run through at least one full cycle, four years, and probably two cycles” to eliminate naturally occurring variability, Myrbo said.

Wild rice can be deeply affected by short-term weather phenomena, like June’s record rain and floods, which have nothing to do with the chemical makeup of the water. “We’ll get a data set,” Myrbo said. “But we really need more years – a larger data set.”

The Chamber’s Robertson said his group is still hopeful that the PCA can develop its standard soon after the data comes in next year.

“We hope it doesn’t go too much longer. We have (mining companies) permittees out there that need to have this standard decided before they can move ahead,” Robertson said. “And we hope what they come up with will last. We’re talking tens of millions of dollars for the companies to develop a protocol to meet the standard, so we certainly don’t want to see it become a moving target.”

In the end, it will be up to the PCA to interpret the findings and use them to justify keeping the current standard or change it.

“Science won’t be able to pick a line and say `that’s it.’ That’s going to be up to the PCA. It’s going to be a values decision, based on the science,” Pastor said. “If they simply wanted a protective standard for rice they could have kept what they have. But that wasn’t good for some people, so here we are.”

PCA officials are making it clear that the research must clearly justify a change or the old sulfate standard will not only remain in place, but it will be written into more industrial permits for water discharges into wild rice waters.

No matter what results the scientists get, even if they are clear-cut, it could be several years until any changes are made in the state regulations. Tomasek said the agency hopes to have a sense of the scientists’ work by late 2013 or early 2014. They could then make an internal decision and began the elaborate administrative law change effort, which would be late 2014.

But the change also would have to be approved by the federal Environmental Protection Agency, which would likely take several more months, well into 2015 according to a PCA timeline.

In the meantime, the old standard remains in place for industry to meet.

“EPA still has the final say on any changes to our water quality standards,” Tomasek noted. “We’re bringing them in early in the process . but it’s still going to be a long process.”
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