Toxic Algae Bloom Confirmed in Western Lake Erie

Julie Mida Hinderer is a research assistant at the NWF Great Lakes Regional Center, working on a report on nutrients and harmful algal blooms.

Algal bloom at dock
A harmful algal bloom in western Lake Erie. Photo by NOAA GLERL.

It’s official – western Lake Erie is experiencing its first toxic algae bloom of the year. The bloom consists of a species of algae, Microcystis, which pumps out toxins that can cause severe illness, liver damage, and even death in humans and wildlife. Harmful algal blooms like the current one are a symptom of eutrophication, a phenomenon caused by excess nutrients such as phosphorus that wash into streams and eventually the Great Lakes from cities and farms.

Current policy proposals and Federal spending cuts endanger programs that protect and restore water quality in Lake Erie. Take action today and urge your federal officials to protect our nation’s conservation laws.

The harmful algal bloom in western Lake Erie was first reported by the National Oceanic and Atmospheric Administration’s Center of Excellence for Great Lakes and Human Health using satellite imagery in mid July. By July 28, the Center’s in-lake sampling confirmed that “…a very high level of toxins has been observed near the Toledo Light #2 (>1000 ug/l).”

For comparison, World Health Organization guidelines state that concentrations of Microcystis toxins higher than 1 ug/l are unsafe for drinking water, and concentrations above 20 ug/l pose moderate recreational risk from contact with contaminated water.

There is no cause for alarm just yet, however. According to the Ohio Environmental Protection Agency, the current Microcystis bloom is not near any beaches or drinking water intake locations. In addition, toxin concentrations have declined and no toxins have been detected in the finished water supplies of utilities currently monitoring in western Lake Erie. Despite these good signs, the bloom may be headed for the Bass Islands, a popular tourist destination.

Although algae and associated toxins are usually successfully removed during the drinking water treatment process, blooms of blue-green algae can cause taste and odor problems that persist after treatment.

In Lake Huron’s Saginaw Bay, an area prone to large blue-green algae blooms, utilities are currently struggling to rid drinking water of an unpleasant “musty” flavor caused by a compound released during algae removal. So far this year, no taste and odor problems have been reported in finished water from western Lake Erie.

Blue-green algae are naturally present in Lake Erie. When conditions such as temperature and nutrient levels are just right, however, large blooms can form rapidly.

In recent years, harmful algal blooms have become more common across the Great Lakes, especially in western Lake Erie, even though the total amount of phosphorus entering the lake has not increased. The underlying cause of the explosion of algae blooms in western Lake Erie is uncertain, but agricultural practices may be contributing larger amounts of biologically useful phosphorus than in the past. In addition, researchers suspect that invasive zebra and quagga mussels have altered nutrient cycling, concentrating phosphorus near shore and converting it to forms readily used by toxic algae.