The Impacts of Harmful Algal Blooms on Human Health in the Great Lakes

J. Dyble1, G.L. Fahnenstiel1, S. Joseph1, P.A. Tester2, R.W. Litaker2 and D.F. Millie3

1 NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI  48105
2 NOAA, Center for Coastal Fisheries and Habitat Research, Beaufort, NC 28516
3 Florida Institute of Oceanography, St. Petersburg, FL  33701

A significant threat to the water quality in many regions of the Great Lakes is the recent resurgence of cyanobacterial Harmful Algal Bloom (HAB) species.  Of particular concern is freshwater HAB genera Microcystis, which can form thick surface blooms and produce the hepatotoxin microcystin.  Microcystin can have detrimental impacts on multiple levels, from disruption of zooplankton grazing to illness and mortality in animals and humans.  Human exposure to microcystins can be through drinking water, recreational exposure and potentially fish consumption.  Microcystin concentrations exceeding the World Health Organization’s recommended limit for drinking water (1 µg L-1) are frequently present in western Lake Erie and Saginaw Bay (Lake Huron) during the summer months and concentrations exceeding the recommended recreational exposure limit (20 µg L-1) can often be found in surface scums.  As part of the Oceans and Human Health Initiative, the NOAA Great Lakes Environmental Research Laboratory (Ann Arbor, MI) has been established as the Center of Excellence for Great Lakes and Human Health, with the goal of using ecosystem forecasting as a means to minimize risks to human health in the Great Lakes associated with beach closures, HABs and drinking water quality.  Current research includes mapping Microcystis cell densities, measuring microcystin concentrations in the water column, zooplankton and fish and using genetic markers to identify the presence of toxic Microcystis strains in recreational and drinking waters.