District Health Department #2 staff samples & monitors certain public bathing beaches for levels of Escherichia coli (E. coli) bacteria during the summer season. Many bathing beaches along the Great Lakes shoreline, and at inland lakes are sampled to determine if E. coli are within safe levels established under Michigan law. Funding to conduct the bathing beach monitoring program comes from the Michigan Department of Natural Resources and Environment in the form of a grant and also by way of contractual arrangements.
What is E. coli?
E.coli is an indicator organism that is found in the intestinal track of warm blooded animals, such cattle, deer, dogs, waterfowl, and humans. It may be present in high levels due to contamination from wastewater from human activities, or from animal waste that has been deposited into the lake or nearby stream.
What are the Health Effects of E. coli?
High levels of E. coli in bathing beach waters has been associated with gastrointestinal illness and also with respiratory illness.
What is the Michigan Standard for E. coli Levels at Bathing Beaches?
There are two different standards for E. coli in bathing beach waters: one is a single day sampling event and the other is the 30 day average. A “sampling event” is the geometric average of three (3) samples collected at a bathing beach location.
1) Single day sampling event standard: 300 E. coli colonies per 100 ml.
2) 30 day average of at least 5 sampling events: 130 E. coli colonies per 100 ml.
What if Bacteria Levels are High?
Typically E. coli levels are low at Great Lakes and inland lakes beaches in the four counties of District Health Department #2. However sampling experience has shown that certain naturally occurring events may cause high levels of E. coli in bathing beach waters. Storms may result in runoff water laden with fecal material from farming activity, waterfowl, or sewage discharges. Additionally, on shore winds may concentrate contaminated storm runoff against the beaches where algae and other debris may concentrate bacteria resulting in high levels of E. coli.
Should water samples indicate that the E. coli standards have been exceeded District Health Department #2 staff will then contact the beach operator, post the beach area with an advisory to avoid full body contact, re-sample until safe sample levels are obtained, and review the site to try and determine the cause of the high bacteria levels.
Where to Find Results of Bathing Beach Samples?
All sample results for bathing beaches, for both Great Lakes and inland lakes, can be found at the DEQ Beachguard website for beach monitoring. Advisories due to high levels of E. coli will also be posted at this same site. (See the link to the right)