A toxin produced by a kind of cyanobacteria contaminated Toledo's water supply over the weekend. It left 400,000 people without drinking water.
Blooms of cyanobacteria (sometimes referred to as blue-green algae) like these happen when excess nutrients — mostly phosphorus — run off into Lake Erie from farms and sewage treatment plants.
The International Joint Commission is an independent organization that gives advice to the U.S. and Canada on Great Lakes issues. Earlier this year, the IJC put out a report on how to prevent these blooms.
Raj Bejankiwar, of the Commission's Great Lakes Regional Office in Windsor, Ontario, is the lead scientist on that report.
Cyanobacteria blooms were a problem in the '60s and '70s, but then they went away and in the 2000s they started coming back. Bejankiwar says it's because of runoff, mainly from farms.
"We have to stop feeding algae their food, which is phosphorus. We use that extensively in the agriculture land and Toledo is right in the ground zero zone for algae, especially the Maumee River watershed." Bejankiwar adds that in the past few years, heavy storms have washed phosphorus-filled fertilizer from farms. "It ends up in the Maumee River and then finally in Lake Erie."