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.
“We 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 Mary Skopec who coordinates the beach monitoring program for the Iowa Department of Natural Resources.
Skopec said blue-green algae can release mycrosystins in the water that can make people and pets ill.
“We don’t want to scare people, as this is a naturally occurring event. It happens every year in our lakes and rivers,” Skopec said. “We just want people to be aware that if the mycrocystins are present, it can cause problems for people or pets.”
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.