MPR’s Stephanie Hemphill reports that a team of researchers has been trying to track down possible sources of the bacteria on the beaches of lake Superior in Duluth. What they've found so far is surprising, and it raises a big question about the standard way of testing for beach contamination.
For three years the Minnesota Pollution Control Agency has been warning swimmers and kayakers in Lake Superior when bacteria levels are dangerously high. The agency repeatedly posted a few Duluth beaches as being unsafe.