Earlier this month, Toledo was forced to ban residents from drinking or cooking with their tap water when unsafe levels of microcystin were detected at the Collins Park Treatment Plant. The toxin is produced by the green algae that grows in Lake Erie and is more potent than DDT, mercury and cyanide.
When rains hit the farms of Ohio, Indiana and Michigan, phosphorous is washed into the rivers and streams that flow into the Great Lakes. Lake Erie, the shallowest of the lakes, is the perfect environment for the algae to grow.
“Most water treatment plants are watching for the toxin,” says Don Scavia, the director of the Graham Environmental Sustainability Institute at the University of Michigan. “The options when it occurs are to treat it – very expensive – or to shut down.”
These blooms occur across the United States and the globe. In salt water environments, algal blooms lead to the creation of dead zones when microbes consume the algae and eat up all the oxygen in the water. This kills any marine life that lives in or swims through the area. In the Gulf of Mexico, the dead zone created by agricultural runoff from the Mississippi River is currently the size of Connecticut. Last year it was the size of Massachusetts.
The process of runoff contaminating water supplies is known as “eutrophication.” A 2008 article in Environmental Science & Technology calculates that the potential value losses from eutrophication in U.S. freshwaters – in recreational water usage, waterfront real estate, drinking water and spending on recovery of endangered species – could equal up to $2.2 billion per year. And this problem is likely to get much worse if current agricultural and environmental policies continue.
Warmer summers, stronger storms and longer growing seasons are ideal for growing cyanobacteria. These conditions are caused by climate change and lead to earlier and longer lasting algal blooms. But the amount of fertilizer and other additives used on farms is also increasing, and that has made the runoff that much more potent.
Currently, the only means of regulating agricultural phosphorous are voluntary ones and “[t]hey aren’t enough,” according to Rajesh Bejankiwar, leader of the International Joint Commission tasked with mitigating phosphorus pollution in the Great Lakes. Over 60 percent of the phosphorous entering the water is coming from farms within the Lake Erie Basin. In recent years, this has resulted in bigger and more toxic algal blooms.