Green Valley Lake testing high for microcystins

Nearly every summer, the Iowa Department of Natural Resources sends out a series of press releases saying Green Valley Lake in Creston has tested positive for high levels of microcystins.

That has been the case again this year. Test results came back Friday indicating the lake still had high levels of microcystins.

The high levels of microcystins are the result of agricultural runoff entering the lake through tributaries or from natural nutrients in the lake. That, combined with warm, dry weather, causes the nutrients to bloom into blue-green algae.

The blue-green algae on the lake is dangerous for humans, pets and livestock if they come into contact with it.

The most common human symptom is a rash from the direct contact with the algae. But, more severe symptoms, such as upset stomach, diarrhea and nausea, can happen.

“For some people, it could be more severe,” said Amanda Husband, Union County environmental specialist. “I would expect to see those type of symptoms coming from the young, the old or the immune-compromised folks.”

With the dangers posed by coming into contact with the blue-green algae, both Husband and the DNR suggest people avoid swimming and other direct-contact activities at the lake.

That includes skiing and tubing. Fishing, however, is OK.

“As long as you’re in your boat where you’re not having direct-water contact or you’re fishing from the side,” Husband said. “And yes, you can eat those fish. They are safe. Just clean out the guts to them and rinse them off good.”

Husband also suggests keeping pets on a leash around the lake so they do not jump into the lake or come into contact with the dried algae near the shore.

The blue-green algae can have a deadly effect on pets.

“If that pet gets down into that water, they’re really highly susceptible to this because they can get that algae on their fur and their paws and they lick it off,” Husband said. “So, they’re getting a really high dosage of it and they can go into liver failure pretty quickly.”

Animal symptoms include lethargy, vomiting, diarrhea, convulsions, difficulty breathing and general weakness. Signs of poisoning may appear in pets within 30 minutes after ingesting toxins.

Pet owners should carry a water bottle with them when walking their pets around the lake, giving the pet drinks from the bottle as opposed to allowing the pets to drink from the lake.

“You’d have to drink quite a bit to go into liver failure as a human, and I think you would be grossed out before that,” Husband said. “But pets, they get that matte algae on them and they don’t know any better than to lick it off. They’re a lot smaller animal than we are by mass.”

The DNR tests the lake every week and results are often posted Friday afternoon. When microcystin levels are high, signs are posted near the lake warning people of the dangers.

“If we get cooler temperatures and we get some rain, I would expect (the levels) to dip back down,” Husband said. “It’s like every year, it gets in that warm, hot, dry period of summer and we’re going to test positive. That’s how that lake is going to be. People need to be aware of that.”

For up-to-date information on microcystin levels, visit www.facebook.com/UnionCountyEnvironmentalHealth or www.iowadnr.gov/Things-to-Do/Beach-Monitoring.