In early August, residents of Toledo, Ohio, were told not to drink the water.
Toledo's drinking water comes from Lake Erie, where a harmful algae bloom that creates a toxin called microcystin had been growing. When ingested, that toxin can cause diarrhea, vomiting and liver-function problems. It can also kill dogs and other small animals that drink contaminated water.
Could it happen here?
Here in Minnesota, blue-green algae makes the news nearly every summer when conditions are ripe — hot and dry. So, could Minnesota end up with the same issues as Toledo?
The short answer, no. Most Minnesotans do not get drinking water from lakes, where this type of algae can flourish. Nearly 75 percent of our drinking water comes from groundwater. Most of the other 25 percent comes from rivers or reservoirs fed by rivers. Algal blooms thrive in calm, warm, shallower water bodies.
While not seeing the same impact on drinking water as Toledo, Minnesota and other Midwestern states are seeing an increase in these toxic blooms, which are driven by increased nutrients like phosphorus and nitrogen getting into our waters. Sources of phosphorus and nitrogen that are common to both Minnesota and Ohio waters include runoff from farms and urban yards, as well as discharges from wastewater treatment plants.
Climate change may also be contributing to algae blooms across the states. Warmer temperatures can lead to more blooms.
The Minnesota Pollution Control Agency studies the harmful of effects of phosphorus and nitrogen and has worked for decades to limit pollution from wastewater treatment plants and sewer pipes by creating tougher standards. That work is paying off as phosphorus from wastewater has decreased. So if phosphorus from wastewater is decreasing, that means we have to reduce the amount of phosphorus leaving farm fields, lawns, roads and urban stormwater. This is a bigger challenge, because some of these sources are not regulated like wastewater treatment plants.
It’s not an easy task to reduce the amount of phosphorus and nitrogen going into our waters, but Minnesota has shown progress. In 2008, Minnesota's voters showed their passion for the state’s water resources by passing the Clean Water, Land and Legacy Amendment. This gives additional funding to state agencies to monitor, assess, protect and restore our waters — this includes working with farmers, land owners, cities, wastewater treatment plants and many other organizations to find solutions to a very tough problem.
For more information
To find out more about harmful blue-green algae, visit MPCA's blue-green algae webpage.