October 17, 2011
Health agency completes first season of Lake Superior beach monitoring
Majority of water quality problems occur at a few beaches
The vast majority of beaches along Minnesota's Lake Superior shore had no days of closure or use restrictions due to poor water quality during the 2011 recreational water use season, state health officials reported today. A few beaches accounted for most of the health advisories.
The Minnesota Department of Health (MDH) concluded its first year of the Minnesota Lake Superior Beach Monitoring Program on Sept 30. MDH regularly sampled 37 beaches along the shore of Lake Superior this summer after assuming operation of the program from the Minnesota Pollution Control Agency (MPCA). The purpose of the program is to monitor beaches for E. coli levels and to notify the public when the waters exceed an acceptable level of E. coli bacteria.
The beach monitoring program reported that 22 beaches had no advisory events and 10 had 1 advisory event in 2011. In 2009, 24 beaches had no advisory events, 7 had 1 advisory event. Health advisories were posted at beaches when bacteria measured too high for safe water contact.
Fewer beaches in 2011 had two or more advisory events than in 2009 (2010 was a transition year between programs so limited data are available). In 2011, only 5 beaches had 2 or more advisories posted. In 2009, 8 beaches had 2 or more advisories. However the total number of advisory days (the total number of days each beach had a sign posted on it) was more in 2011 than in 2009: 169 in 2011 compared with 76 in 2009.
"Interestingly, the beaches that had more elevated levels of E. coli bacteria in 2009 are not necessarily the same ones that had high numbers in 2011," said Amy Westbrook, MDH district epidemiologist in Duluth. In 2009, for example, Clyde Ave. boat landing (located on the St. Louis River estuary) had 32 advisory days, but in 2011 there were only 9 at that site.
Two Duluth beaches accounted for 129 advisory days, or 73 percent of all health advisories.
"From these data, it's clear that the majority of repeat closures occurred at just a few sites," Westbrook said. "We are working with our many partners in water quality in the state and the Northeast region to investigate what might be done to determine the reasons for the repeat problems at these few beaches and then what might be done to improve the water quality at those beaches."
Under the Minnesota Lake Superior Beach Monitoring and Notification Program, staff checks the water quality primarily for the presence of E. coli bacteria, which can be a health risk and are also an indicator of the presence of other potentially harmful pathogens or contamination. The most heavily used beaches, in the Duluth area, were tested twice weekly, the others once a week. The results were posted immediately on a telephone information line and the program's website.
Of the 755 samples taken in 2011, 86.5 percent were found to have safe levels of bacteria, compared to 93.5 percent in 2009.
For more information on the program, visit www.MNBeaches.org. Staff are available to speak at community meetings about the program. Contact the MDH Duluth District Office at 218-723-4642.
MDH District Epidemiologist