NOAA Center of Excellence for Great Lakes and Human Health: Making strides in Forecasting, Partnerships, and Public Awareness

A glass of bright green water with high concentrations of bluegreen alga

High concentrations of Microcystis cells can at times turn the surface waters bright green. (photo by T. Bridgeman, U. of Toledo)

With the summer months speedily approaching, residents of the Great Lakes Basin, as well as thousands of visitors from around the United States, are looking to the cool, refreshing waters of Great Lakes to relax, recreate, and rejuvenate. With over 600 recreational beaches in the Basin, and home to the largest freshwater body in the world, the Great Lakes are recreational paradise.

With the warmer weather, however, also comes a potential risk. At times when these shallow waters are stratified, the surface becomes coated with green paint-like flecks. These are blooms of the microscopic blue-green algae (cyanobacteria) Microcystis and are common in parts of western Lake Erie, Saginaw Bay ( Lake Huron ) and some inland lakes. Of particular concern is the production of the hepatotoxin microcystin by some strains of Microcystis. Microcystins have been shown to be detrimental to the health of humans, animals and the ecosystem, leading the World Health Organization (WHO) to set a recommended guideline of 1 µg L^-1 for drinking water supplies and 20 µg L^-1 for recreational exposure causing moderate risk.

Map of Saginaw Bay showing concentrations of microcystin toxin above the WHO limit for drinking water.

Microcystin concentrations (in µg L^-1) in the surface water of Saginaw Bay (Lake Huron) during August 2004. Black dots indicate sampling stations and all of the shades of orange indicate microcystin concentrations above the WHO's recommended 1 µg L^-1 limit for drinking water consumption.

Researchers at the Center of Excellence for Great Lakes and Human Health (CEGLHH) , located in NOAA's Great Lakes Environmental Research Laboratory in Ann Arbor, MI, have been investigating the distribution of Microcystis and microcystin in the shallow, eutrophic regions of the Great Lakes and the factors (physiological, environmental and genetic) controlling the production of these toxins. Surveys of microcystin concentrations in August 2004 and August 2005 have shown that surface water microcystin concentrations frequently exceed this WHO limit. Concentrations as high as 58 µg L^-1 were measured in surface scums in western Lake Erie near South Bass Island.

In May 2005, CEGLHH launched a Harmful Algal Bloom Event Response website to raise public health hazard awareness after harmful algal blooms occurred on southeastern Lake Michigan and western Lake Erie. The website was created with results of NOAA's research program that focuses on understanding factors affecting toxic algal bloom growth in the Great Lakes region.

A listserv “Habcomm” was also created in an effort to foster communication among people interested in learning about algae blooms in the Great Lakes region. Members of this e-mail service include the public health community, researchers, and concerned citizens.

Alga is visible on the water surface at South Bass Island

An alga bloom with high concentration of microcystin toxin is visible at the shore line.

(Left) Microcystis cells visible on the surface of the water at South Bass Island in August 2004.

(Right) Microcystis bloom in which microcystin concentrations of 58 µg L^-1 were measured in August 2004. (photos by J. Dyble, GLERL)

This summer, the Centers for Disease Control and Prevention (CDC) is planning to conduct an epidemiological study to complement the microcystin research being conducted by the Principal Investigators (PIs) of the Great Lakes and Human Health center, Dr. Gary Fahnenstiel and Dr. Juli Dyble. The center will be working with the CDC to develop informational pamphlets to disseminate to the public at the sites where the epidemiological study will take place to raise awareness on potential health risks associated with harmful algal blooms. Researchers with CEGLHH will continue to use a multidisciplinary approach to understand and forecast coastal-related human health impacts, including those resulting from Microcystis and other cyanobacterial HABs in the Great Lakes.