Great lakes algae blooms causing havoc with water supply

Great lakes algae blooms are causing havoc with water supply in surrounding states. Most algae blooms are not toxic, but some algae secrete toxins are are therefore classified as "HABs" i.e. harmful algae blooms. The U of Michigan article below explains

"The most dominant blue-green algae in the Great Lakes is Microcystis which can produce Microcystin, a liver toxin and skin irritant."

This site gives a good explanation. It explains that toxic algae blooms occur both naturally and also due to a variety of factors including excessive fertilizer runoff and invasive species.

Harmful algae blooms in the Great Lakes
http://www.miseagrant.umich.edu/explore/coastal-communities/harmful-algal-blooms-in-the-great-lakes/

A branch of NOAA called the Great Lakes environmental research Laboratory is working on the problem and surrounding states have passed legislation.
http://www.glerl.noaa.gov/res/waterQuality/