A popular late-night swimming spot in Lake Mendota near Memorial Union could pose a health risk due to blue-green algae, which appears to have sickened one person after an early morning swim last week, the Madison-Dane County Health Department said Tuesday.
Kirsti Sorsa, environmental technical services supervisor for the department, said the possible presence of the algae in a location frequented by nighttime swimmers “certainly could be ” a potentially serious situation.