DES MOINES – The DNR is posting a swimming and water contact advisory at Big Creek State Park for the July 9 to 10 weekend, or until the lake can be tested, following a significant algae bloom discovered late Friday. A sign will remain at the beach until monitoring results show swimming is safe.
“If you are in an area where it’s visibly showing masses of algae or a blue-green paint color, you should avoid contact with the water and keep pets away from it,” said Greg VanFosson, DNR district parks supervisor.
Rapidly warming weather, water temperatures and the presence of blue-green paint color in the water at Big Creek have prompted concerns about microcystin, a product of blue-green algae.
“We don’t want to scare people, as this is a naturally occurring event. It happens every year in our lakes and rivers,” he said. “We just want people to be aware that if the mycrocystins are present, it can cause problems for people or pets.”
The DNR will take water samples at the lake and test for microsystins. The most recent test results from water sampled at Big Creek on July 5 showed less than 0.10 micrograms of microcystins per liter of water. This is well below the level of concern of 20 micrograms of microcystins per liter of water. However, water quality conditions can change rapidly and the presence of scummy water indicates possibly high levels.
Because the conditions are conducive to blue-green algae growth, people and pets should not be in contact with water that has a poor appearance. The appearance can be a pea-green or blue-green color, but also a reddish-brown. It may appear with scum, foam or as a thick mat on the water surface. Blue-green algae can grow quickly and become very abundant in warm, shallow, undisturbed surface water that receives a lot of sunlight.
The main risk to humans from microcystin is skin irritations and rashes, but if the water is swallowed or airborne droplets are inhaled during swimming, bathing or showering, symptoms could be worse. Those would include headaches, nausea, abdominal pain, seizures, liver injury and respiratory problems.
People can take the following precautions to prevent health-related problems due to harmful algal blooms:
- Don't swim, water ski or boat in areas where the water is discolored or if there is foam, scum or mats of algae on the water.
- If you come in contact with water that might have a harmful algal bloom, rinse off with fresh water as soon as possible.
- Don't let pets or livestock swim in or drink from areas where water is discolored, of if there is foam, scum or mats of algae on the water.
- Don't let pets (especially dogs) lick the algae off their fur after swimming in scummy water.
- Don't irrigate lawns or golf courses with pond water that looks scummy or has a bad odor.
- Don't drink the water. Boiling the water will not make it safe to drink.
When test results indicate swimming is safe, the DNR will remove the sign from the beach and issue a press release.
Test results for other state beaches can be found on the DNR website. Look under Environment and Water quality monitoring at www.iowadnr.gov
or go directly to www.igsb.uiowa.edu/wqm/Beaches/BeachMapState.htm
The beaches at Black Hawk Lake and Lake of Three Fires also had swim advisories posted this week after water samples collected July 5 and 6 showed 20 micrograms of microcystins per liter of water. The DNR will post the advisories until additional samples show the levels have dropped.