Tag: runoff

Michigan public beach advisories increased in 2024

Published on December 11th, 2024 by - Blog Posts

Michigan public beach advisories were up during the 2024 season compared to 2023, with the difference likely due to the timing and intensity of storms that washed polluted runoff into rivers and lakes.

A total of 127 advisories and closures were reported for 106 beaches in thirty-eight counties, by twenty-eight local health departments in 2023. In 2024, 289 advisories and closures were reported for 167 beaches in forty-eight counties by thirty-three local health departments.

“Just my initial observation for 2024 was that beaches were significantly impacted by rain and storms,” said Dr. Shannon Briggs, coordinator of beach monitoring for the state Department of Environment, Great Lakes, and Energy (EGLE). “The dates of the closures are clustered for the beaches. It seemed the storms arrived early in the week and that is when most monitoring occurs.

“Beaches are typically monitored Mondays and Tuesdays. Followup samples are collected on Wednesdays and Thursdays. Most labs don’t take samples on Friday because they have to wait until Saturday for the culture-based results. However, there are some labs that use qPCR methods and can test beaches on Fridays.”

Beach advisories and closures are issued based on an unhealthy level of Escherichia coli (E. coli). In contrast to former testing methods, which took at least 24 hours to yield results, quantitative polymerase chain reaction (qPCR) can yield measurements or estimates of E. coli within several hours. Thanks to the quicker turnaround time, officials can post warnings or close beaches the same day.

When bacteria such as E. coli are present, other dangerous bacteria and viruses that are more expensive to measure may also be present. High levels of E. coli signal that microorganisms of concern to human health, such as Salmonella and norovirus, may also be in the water.

Statewide, 530 beaches in sixty-seven counties were monitored by thirty-seven local health departments in 2023. In 2024, 521 beaches in sixty-seven counties were monitored by thirty-seven local health departments.

The monitoring of beaches in Michigan is voluntary and is conducted by the local health departments. State law requires that a local health officer or an authorized representative of a local health department that conducts tests at bathing beaches is required to notify the department and other entities of the test results within 36 hours of conducting a test or evaluation. Owners of public bathing beaches must post a sign that states whether the bathing beach has been tested, and if so, the location of the test results.

Monitoring results for Michigan’s public beaches – roughly 600 Great Lakes and 600 inland beaches, are on EGLE’s Beachguard website.

Are the Great Lakes really “unsalted and shark-free” ?

Published on October 2nd, 2024 by - Blog Posts

A popular vehicle decal says the Great Lakes are “unsalted and shark-free.”

Is it true?

Not if you consider road salt and salt from water softeners. In 2021, scientific researchers estimated chlorides in Lake Michigan had risen from about 1-2 milligrams per liter before European settlement to more than fifteen milligrams per liter. Canadian researchers found levels ranging from 1.4 milligrams in Lake Superior to 133 milligrams per liter in Lake Ontario. Although these levels are well below the chloride concentrations in ocean water (about thirty-five grams per liter) and below the aesthetic standard for chlorides in drinking water (about 250 milligrams per liter) rising concentrations of chlorides may have ecological effects. These include killing or damaging aquatic plants and invertebrates.

The study of Lake Michigan salinity levels found that watersheds with a greater area of roads, parking lots and other impervious surfaces tended to have higher chloride levels due to direct runoff into streams and lakes.

Although road salt is likely the largest single source of chloride pollution of the Great Lakes, livestock, fertilizer, and water softeners also contribute. Still, the easiest solution to rising chloride levels in the Great Lakes is to use less road salt, and transportation officials have searched for ways to apply less salt on roads during the winter, while keeping roads clear and safe for motorists. The most direct way is to put salt on fewer roads. In some cases, sand or ash is used as an alternative to rock salt in lower-traffic areas.

As for sharks, well, there was a report of a bite taken out of a Chicago-area man by a bull shark on Jan. 1, 1955. The best guess of the Chicago Tribune is that it was a hoax published in 1975, the year the movie Jaws was released. So “shark-free” is accurate.