How safe is it to swim in the cold and clear waters of Lake Superior? It depends on where you take the plunge.
Last week, Minnesota Pollution Control Agency officials recommended no water contact at the Park Point New Duluth Boat Club/14th Street Beach in Duluth after E. coli was found there. The week before, an advisory was issued for Duluth’s Southworth Marsh Beach because of elevated levels of E. coli.
More than three dozen Lake Superior beaches in Minnesota are now monitored for contamination. Swimming advisories for the 14th Street location were issued five times last year, covering 69 days — practically the entire swimming season in Duluth. (The state of Minnesota does not close beaches, but only issues advisories. Cities and counties can close beaches.)
“In general, Lake Superior is very safe,” said Heidi Bauman, the MPCA official in charge of monitoring the beaches in Duluth. “My kids and I swim there — when weather permits, of course.”
Data on beaches and beach closings in the Great Lakes and elsewhere are compiled on websites maintained by the MPCA and the federal Environmental Protection Agency. The sites also contain information on current conditions.
In 2007, the EPA reported that 32 percent of monitored beaches around the country were closed or advisories were issued at least once because of contamination or as a precaution. The federal monitoring program began nationally in 1997, expanding to include Minnesota in 2003. The highest number of closings was reported in 2006 and 2007.
Also keeping tabs is the National Resources Defense Council, which crunches the numbers in a different way. Its 2007 report won’t be available for a few weeks, but it reported that in 2006, 14 percent of Superior-Minnesota beaches exceeded national E. coli standards in at least one sample.
Nationally, Minnesota was the fifth-worst among the 30 states surveyed. Ohio was the worst offender with 22 percent of its beaches exceeding E. coli standards, followed by New York and Indiana at 19 percent, Illinois at 15 percent, and then Minnesota.
In urban areas sampled, Duluth was the cleanest among Cleveland, Toledo, Milwaukee and Chicago.
Three beaches on the harbor side of Park Point in Duluth — 14th street, Southworth and Hearding Island — account for 80 percent of the Minnesota advisory days, Bauman said. The beaches are in an active harbor with a lot of ducks and geese (read: poop) and less cleansing wave action than the main lake, she said. “It just sits there and cooks.”
Using E. coli samples to justify advisories has become controversial, especially after recent studies by University of Minnesota-Duluth researchers and others indicated that a certain amount of the bacteria lives naturally on the beach.
“I always tell people not to swim in a metro lake for 24 hours after a good rain,” Bauman said. Possible contaminants wash into the lake without filtering through a sewage treatment plant and have not had a chance to break down via sunlight, she said.
Most of the time, federal and state officials can’t pinpoint the source of the contamination unless it is from storm water runoff, or less often, sewage leaks or overflows.
E. coli can cause gastrointestinal illness — anything from a stomach ache to severe vomiting and diarrhea — and can be dangerous to the very young, the very old, or those who are already ill.