DES MOINES – Water samples taken throughout the last week indicate that toxins released from a blue-green algae bloom are declining at Big Creek Lake.
The presence of blue-green paint color in the water was not visible until early Sunday evening at Big Creek Lake prompting concerns about microcystin, a product of blue-green algae.
Water samples taken on Sunday and Monday indicated levels of microcystin above the World Health Organization’s recommendation of 20 parts per billion. Subsequent water samples drawn from the lake later in the week indicated levels below the recommended advisory level for all but a few isolated spots on the lake where wind had blown algae up against the shore.
“We still recommend that 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.
“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.”
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.