DULUTH, MN (KDAL) – According to recent research, steel structures in inland lakes and rivers in northern Minnesota are seeing similar corrosion as was documented in the Duluth-Superior harbor.
The corrosion of steel pilings was first noted in the Twin Ports harbor in 1998. Research funded by the Minnesota and Wisconsin Sea Grant programs identified microbes that interacted with water and steel as the cause of the corrosion that leaves pockmarks and holes in underwater steel structures.
Although initially thought the issue was specific to Lake Superior, the problem has become widespread with gates on the St. Louis River and docks on Fish Lake, Island Lake, Grand Lake and others showing bio-corrosion.
Professor emeritus at UMD, Randall Hicks, doesn’t think it is just a regional problem and says it has been happening for a long time in places where conditions are right. He says those conditions include the presence of sulfate reducing and iron oxidizing bacteria and low oxygen in the water.
Previous research has identified coatings that can protect the steel and now Hicks is working on a lactonase enzyme treatment that would reduce the biofilm that accelerates the corrosion.
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