Ohio To Combat Harmful Algae Blooms In Lake Erie

Ohio EPA has released the draft 2020 water quality report that outlines the general condition of Ohio’s waters and includes a list that identifies impaired waters that are not meeting their federal or state water quality goals, as well as waters that have improved to meet their goals.

Despite millions of dollars spent to reduce toxic algae in Lake Erie, research has shown no decrease. Lake Erie's shallower and warmer western basin has been classified as impaired since March 2018, not meeting federal or state water quality goals.

For 2020, Ohio EPA is placing a high priority on Lake Erie’s Western Basin (from the Michigan/Ohio state line to the Marblehead Lighthouse) for impairments to recreation and drinking water due to harmful algae and microcystin.

Ohio EPA had previously designated the Western Basin as impaired for these reasons in 2016 and 2018. As a result of the new high priority designation, Ohio EPA will develop a Total Maximum Daily Load (TMDL) for the Western Basin over the next two to three years.

Since the late 1990s, Lake Erie has been plagued with blooms of toxic algae that turn its waters a bright blue-green. These harmful algae blooms are made up of Cyanobacteria that produce the liver toxin Microcystin. The blooms have led to public warnings to avoid water contact, and entire community water supplies can be shut down.

In late summer, Cyanobacteria called Microcystis are found in Lake Erie's open waters. From spring through fall, another Cyanobacteria genus, Planktothrix, blooms closer to shore. Nutrients that fuel Cyanobacteria blooms usually come from the nitrogen in agricultural runoff; the runoff makes its way into streams and rivers, eventually flowing into large waterbodies such as lakes.

Areas near shore are prone to nitrogen loss as summer progresses and the amount of rainfall - and runoff - decreases. Nutrients from spring rains spark Planktothrix blooms, but their persistence through late fall is due to the ability of the Planktothrix Cyanobacteria to "scavenge" nitrogen from their environment better than Microcystis can.

Nitrogen seems to be the common driver for toxic blooms of Planktothrix not only in Lake Erie, but worldwide. The size of a bloom isn’t necessarily an indication of how toxic it is. For example, the toxins in a large bloom may not be as concentrated as in a smaller bloom. Each algal bloom is unique in terms of size, toxicity, and ultimately its impact to local communities.

Harmful algal blooms (HABs) of Cyanobacteria (blue-green algae) in Lake Erie can produce toxins that can pose a risk to drinking water, cause skin irritation, and negatively affect wildlife, companion animals and livestock.

Ohio EPA will present information about the draft impaired waters list through a webinar on March 2, 2020, at 2 pm. The webinar may be viewed at Ohio EPA’s Central Office in the Center for Excellence, 50 West Town Street, Suite 700, Columbus, or by joining online.