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Green Valley Lake microcystin levels high

Published: Monday, July 17, 2017 10:49 a.m. CDT • Updated: Monday, July 17, 2017 10:52 a.m. CDT

The Iowa Department of Natural Resources has identified a hepatotoxin, called microcystin toxin, in Green Valley Lake near Creston in Union County. Microcystin toxin is released by blue-green algae or cyanobacteria.

Cyanobacterial blooms can form in warm, slow-moving waters that are rich in nutrients such as fertilizer runoff or septic tank overflows. Blooms can occur at any time, but most often occur in late summer or early fall. 

Both humans and animals can get microcystin poisoning from exposure to contaminated water. People can get microcystin poisoning from being exposed to contaminated waters, either by intentionally or accidentally swallowing water, by having direct skin contact (as when swimming, wading or showering) or by breathing airborne droplets containing microcystins, such as during boating or waterskiing. Microcystin poisoning can’t be spread from one person to another nor from an animal to a person.

Symptoms may take hours or days to show up in people, but normally show up within one week after exposure. 

Symptoms of microcystin exposure/poisoning include: 

• Rash, hives or skin blisters (especially on the lips and under swimsuits). 

• Gastrointestinal symptoms such as stomach pain, nausea, vomiting, diarrhea, severe headaches and fever. 

• Runny eyes and nose, cough and sore throat, pleuritic pain, asthma-like symptoms or allergic reactions. 

• Exposure to large amount of microcystin can cause liver damage.

Signs will be posted when tests exceed safe levels. 

If there are any questions, contact Union County Environmental Health at 1701 Commerce Road in Creston or call 641-782-7803.

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