I disagree with your editorial last week and your assertion that the effort to re-define the sulfate standard is just about mining.

 According to the Minnesota Pollution Control Agency (MPCA) the sulfate standard applies to “both natural stands and commercial rice fields.” This 10 mg/liter sulfate upper limit protects water used for production of wild rice during periods when the rice may be susceptible to damage by high sulfate levels. These wild rice stands can be existing stands in a water body, or they can be previously documented stands present within a water body dating back to Nov. 28, 1975.”

While I am sure that mining opponents were licking their lips in anticipation of the MPCA declaring that the 10 mg/L standard should continue to be the norm, the study actually showed that there are variables that come into play when deciding where the 40-year-old standard should be enforced.

 One of those variables happens to be the presence of iron the water, and gee, PolyMet happens to be on the Iron Range.  According to MPCA Commissioner John Linc Stine, “Sulfide in sediment porewater is affected by the amount of sulfate in the water column and the amount of iron in the sediment. The presence of iron has a strong role in controlling the level of sulfide in the sediment porewater.  If the iron supply is greater than the production of sulfide, then iron can precipitate sulfide as it is produced yielding lower sulfide levels.”

 The Department of Natural Resources has a great interactive map showing where known wild rice stands are in the state as well as test sites for sulfates.

 While navigating this map I found the following:

 In Champlin, where 169 crosses the Mississippi River, the sulfate value measures 19.45 mg/L.  Just a quarter mile downstream, where the Rum River enters the Mississippi is a known wild rice stand.

 In Redwood County, Timms Creek shows a sulfate value of 218 mg/l while less than three miles downstream there is a known stand of wild rice and another three miles downstream of the wild rice, sulfate was measured at 113 mg/L.

 Bostick Creek, in Lake of the Woods County, measures sulfates at 34.60 mg/l yet just about three miles downstream the MPCA has identified a wild rice bed.

A test site on Lake Vermilion’s Big Bay showed a sulfate standard of 14.60 mg/l while less than a mile away is a 250-acre wild rice stand.

 Bob Bay, in Birch Lake, is notorious in mining opponent circles because of the famous Dunka Pit. Yet, less than three miles downstream, in the Kawishiwi River, the sulfate value is measured at only 1.50 mg/l.  The Dunka River runs right through the still-operating North Shore Mine, however, the sulfate measurement a mere three-quarters of a mile from where Dunka enters Birch Lake is 6.42 mg/l and another three-quarter of a mile downstream is a 381-acre bed of wild rice.

 You claim in your piece that the standard will be enforced on a case by case basis, but that is not what the rule says.  And if there are exceptions to the rule in Blue Earth, Anoka and Redwood counties and if in fact, as the studies show, the amount of iron in the water can change whether sulfates turn into sulfides, than the Range delegation was right in asking for clarification on the MPCA study before recommendations were offered.

 Again, according to Commissioner Stine, “There are many questions and considerations yet to be discussed about protecting the health of our state’s wild rice. These questions cannot be answered definitively today.”

Mary Tome

Fall Lake Twp., Minn.

Editor’s Note:

Ms. Tome is correct that the presence of iron in the water has the potential to mitigate the impact of sulfate levels above 10 mg/l. That’s why MPCA enforcement officials have stated to me that the standard, if ultimately set at 10 mg/l, will be assessed on a case-by-case basis depending on the particular chemistry of the receiving waters. If waters on the Iron Range are high in iron, as seems likely, the receiving waters could receive higher sulfate discharge without impact to wild rice. Thus a higher discharge would very likely be permissible, and allowable under the law. M.H.