MATTOON, Ill. (WAND) - A warning has been issued discouraging swimming in Lake Mattoon due to a toxic algae bloom.
The City of Mattoon has issued a “Do Not Drink” advisory for all residents connected to the city’s water supply after tests revealed the presence of microcystin, a harmful algae toxin.
Lake Mattoon Marina and Campground posted to Facebook telling people not to swim in the lake until further notice.
According to officials, samples taken from the Mattoon Water Treatment Plant detected microcystin levels at 0.35 parts per billion (ppb)—exceeding the state’s advisory threshold of 0.3 ppb. The toxin is linked to harmful algal blooms and can pose serious health risks if consumed.
Residents should not drink tap water, only use bottled water for drinking, preparing food and baby formula, brushing teeth, washing dishes, and making ice. They should also not attempt to treat the water. Boiling, freezing, filtering, or adding disinfectants will not remove the toxin.
People are urged to continue to use bottled water until further notice.
In an advisory, the city said it will notify the public once tests confirm that the water is safe to drink again.
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