Blue-green algae blooms: stay informed, stay safe

Swimming was not advised at Rock Creek Lake on August 10 due to the presence of a harmful algae bloom.

Swimming was not advised at Rock Creek Lake in August 2013 due to the presence of an algae bloom.

UPDATE: As of Thursday, August 6, DNR has posted 23 beach advisories warning Iowans to stay out of the water at Iowa State Park Beaches due to high levels of microcystin, just one warning shy of the 24 warnings posted in 2013 – the most since DNR began monitoring for the toxin at State Park beaches in 2006. Warnings have been posted at 13 beaches, including five beaches brand new to the list.

Summer is in full swing, and many Iowans are heading to the state’s lakes to swim, paddle, relax and cool off with family and friends. However, many Iowans are being greeted by an unwelcome sight at their favorite swimming spots: toxic blue-green algae blooms.

This type of algae, caused by a combination of high levels of phosphorus pollution and increased temperatures can produce harmful microcystin toxins that can make people sick and be deadly for dogs, livestock and other animals.

The Iowa Department of Natural Resources (DNR) has posted more than a dozen swimming advisories cautioning Iowans to stay out of the water at State Park beaches throughout Iowa so far this summer due to high microcystin levels. Included on this summer’s list are Lake Darling, Pine Lake, Red Haw Lake and Twin Lake West beaches – all first time toxic blue-green algae offenders.*

“The threats posed by toxic blue-green algae blooms are serious,” said Water Program Director Susan Heathcote. “Iowans need to be aware of this problem, the health risks, and know how to recognize and respond to toxic blue-green algae blooms.”

Toxic blue-green algae blooms create green, murky water, visible surface scum and a foul odor. The blooms can spread across the water but tend to accumulate in shoreline areas. Beach warnings are posted by the DNR when microcystin levels exceed 20 ug/liter, a guideline established by the World Health Organization. Contact with water at or above this level can result in breathing problems, upset stomach, skin reactions, and even liver damage. Inhaling water droplets containing toxic blue-green algae can cause runny eyes and nose, cough, sore throat, chest pain, asthma-like symptoms, or allergic reactions.

After tracking microcystin poisoning cases in Iowa as part of a national pilot project, Iowa’s public health leaders recently announced plans to add “microcystin-toxin poisoning” to the list of conditions doctors must report to the Iowa Department of Public Health.

“To rid Iowa of toxic blue-green algae blooms and ensure our lakes are safe and healthy for our families and pets, we must improve our water quality and reduce phosphorus pollution caused by agricultural and urban runoff and wastewater treatment systems,” Heathcote said. “This pollution not only puts our health at risk, but also has negative economic impacts on communities that depend on lake tourism, as well as our environment.”

The DNR monitors 39 State Park beaches for microcystin on a weekly basis between Memorial Day and Labor Day, issues advisories and posts warning signs when conditions are unsafe for swimming. The weekly beach advisories can be found on their website. Last summer, the DNR posted 22 beach warnings for high levels of microcystin during the recreational season.

At this time, DNR only monitors State Park Beaches, so if you swim at other public or private beaches you need to be aware of the potential for toxic blue-green algae this time of year. Not all blue-green algae is toxic, but when in doubt, stay out of the water and call the DNR Beach Monitoring Hotline at 515-725-3434. If you think you or your pets may have been exposed to toxic blue-green algae, thoroughly wash it off with fresh water. If you or your pet are experiencing symptoms associated with high microcystin levels after suspected exposure, seek medical or veterinary care immediately.

Records showing State Park Beaches with documented Microcystin levels exceeding 20 ug/L dating back to 2006 are available on the Iowa Environmental Council’s website.

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