U.S. Geological Survey - Environmental Health

Are Naturally Occurring Microbiological Toxins in Water Resources a Health Hazard?

Aerial photograph of a 2016 cyanobacterial bloom on Lake Okeechobee, Florida

Cyanobacterial blooms, such as the one shown that occurred in 2016 on Lake Okeechobee, Florida, can release toxins. Photo Credit: Nicholas Aumen, USGS.

A growing number of human gastrointestinal, respiratory, dermatologic, and neurologic effects, as well as dog and livestock illnesses and deaths, in the United States have been linked to exposures to algal blooms in recreational lakes and stock ponds. However, the connection between these illnesses and cyanotoxins known to be produced by algal blooms is largely anecdotal.

Abstract Art? Nope! It is a Photo of a Cyanobacteria Bloom

Abstract art? Nope! It's a photo of a cyanobacteria bloom on Elsian Lake, Minnesota. Photo Credit: Jennifer L. Graham, USGS.

USGS scientists retrieve sampler from a boat

USGS scientists retrieve and process samples from an ecological processing monitoring station. Photo Credit: Sean Bailey, USGS.

Our specialized teams of hydrologists, chemists, biologists, and geologists working in laboratories and at field sites have shown that cyanotoxins are present in rivers, lakes, and wetlands across the United States.

Map of the occurrence of microcystins in lakes in the U.S.

United States occurrence of microcystins in lakes in the contiguous 48 U.S. states categorized by World Health Organization relative probable health risk. WHO low, moderate, and high refer to the relative human recreational health thresholds for microcystin exposure. Map not shown to scale. Modified from figure 2 from Loftin and others, 2016.

Questions We're Working On:

USGS scientists are working to determine if cyanotoxins associated with algal blooms are causing a significant health hazard to humans, pets, livestock, or wildlife.

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Page Last Modified: 17-Apr-2018 @ 03:13:13 PM EDT