Late summer is peak season for harmful algae, Iowans encouraged to stay safe at area lakes

Update (8/5/2013):  The Council is maintaining a list of algae-related swimming advisories on our website.

Big Creek Lake was one of several Iowa lakes were public advisories concerning algae blooms were issued in summer 2012.

Big Creek Lake was one of several Iowa lakes were public advisories concerning algae blooms were issued in summer 2012.

Ensuring a safe, enjoyable visit to Iowa lakes this summer means keeping track of water conditions and being aware of potentially harmful algae blooms.

Algae, which are tiny aquatic plants, are abundant in many Iowa lakes because Iowa’s waters frequently have high levels of nitrogen and phosphorous.  In the late summer, when conditions turn hot and sunny, algae growth can increase dramatically, or “bloom,” threatening recreation and causing public health concerns.

“We are especially concerned about algae blooms this year because high levels of nitrogen and phosphorous in runoff from farmland reached Iowa’s waters this spring and early summer,” said Susan Heathcote, the Council’s water program director.  “Now, the sunny and hot conditions in late summer could spur rapid, widespread algae growth.”

Image shows a thick mat of green algae with the text "Let's clean this up!"Algae blooms are a nuisance, resulting in green, murky water and visible surface scum.  However, certain forms of blue green algae can produce toxins that can make people sick and have been documented to kill dogs, livestock, and other animals. Laboratory analysis is needed to determine whether toxins are present, so Iowans should use caution around any algae bloom they encounter.

“Harmful algae blooms can emerge quickly, and they may affect different parts of a lake differently,” Heathcote said.  “At any lake, visitors should rely on their own judgment in addition to posted advisories.  Avoid bright blue or green colored water, thick scums that look like spilled paint, or areas that smell bad.”

According to the Iowa Department of Public Health, health impacts of blue-green algae exposure can occur through swimming, drinking, or breathing airborne toxins from affected areas.  Symptoms include breathing difficulties and skin rash, and children are at greater risk than adults.

The Iowa Department of Natural Resources (DNR) monitors beach safety at 39 state-owned beaches with once-weekly water testing.  Iowans planning to visit a state-owned beach can call a DNR hotline, (319) 353-2613, to hear weekly beach water quality monitoring information.

Through July 16 this year, DNR has detected potentially unsafe toxin levels and issued safety advisories at five state-managed beaches:

  • Crandall’s Beach, Big Spirit Lake, Dickinson County (Water sample on 6/11/2013)
  • Viking Lake Beach, Viking Lake, Montgomery County (Water sample on 6/11/2013)
  • Lake of Three Fires Beach, Lake of Three Fires, Taylor County (Water samples on 7/2/2013, 7/9/2013, and 7/16/2013)
  • Brushy Creek Beach, Brushy Creek Lake, Webster County (Water sample on 7/15/2013)
  • Green Valley Beach, Green Valley Lake, Union County (Water sample on 7/16/2013)

Last year, potentially dangerous toxin levels prompted 20 weekly swimming advisories at 11 state park beaches, or about one quarter of state beaches DNR monitors.

Unlike state-owned beaches, water monitoring practices vary at local beaches around the state and water quality advisories are issued at the discretion of local authorities.

While the timing and severity of algae blooms in Iowa depends on many factors, Heathcote said reducing the amount of nitrogen and phosphorous pollution entering lakes is the best method available to reduce or prevent harmful algae blooms.

“Additional conservation practices to reduce erosion and fertilizer runoff from farmland along with additional wastewater treatment by cities and industries would help ensure lakes will be safe for swimming, fishing, and watersports.  Unfortunately, too often, investments in conservation practices necessary for clean water are not a priority in Iowa,” Heathcote said.

Heathcote said in addition to protecting public safety, investing in clean water for Iowa boosts local economies.  Data from Iowa State University shows lake recreation in Iowa generates nearly $1.6 billion in annual spending and supports more than 14,000 jobs.

“We hope Iowans will recognize the important connection between completing conservation actions on the land and ensuring safe summer recreation in the water,” she said.

Additional resources about this story are available in the Council’s online press room.

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