Latest WICOLA Water Quality Report includes focus on metals and sulfate

June 21, 2024: Every five years, the White Iron Chain of Lakes Association issues a report on the series of lakes at the edge of Minnesota’s Boundary Waters Canoe Area Wilderness. WICOLA has just released its 2023 Water Quality Report, with some important additions from previous years: a focus on metals and sulfate levels. 

That’s because Birch Lake, the southernmost of the chain, is newly listed as impaired for sulfate.  As indicated by orange and brown dots on this map, high sulfate levels were measured at the points of inflow from Dunka River and Unnamed Creek, which carry discharge from mining operations. The yellow dots show areas that still exceed the state standard of 10 parts per million, the standard for wild rice waters.  

The waters in this chain flow to the east and north. North of Birch Lake, the other four lakes– White Iron, Farm, Garden, and Fall Lakes– have not been listed as impaired for sulfate.  

However, the report notes that “All lakes in the WICOL are impaired because of the accumulated methylmercury in fish tissues.”  It also notes the relationship between sulfate and mercury methylation.

The report can be read on the WICOLA website.  See the sections on mercury (pp. 33–40) and sulfate (pp. 40–41).

Map source:  WICOLA Water Quality Report, 2023, p. 41.