JOHNSON COUNTY, Iowa — Trista Lynner of Mount Vernon sat on the sand at Lake Macbride beach as her 3 kids played in the water nearby. She brings them here often during the summer.
“Probably once every other week, a couple times a month,” Lynner said. For her, water quality isn't a concern. “It's one of the nicer ones,” she said of the beach.
Even so, Mary Skopec with the Iowa DNR is testing the water to make sure it's safe to swim in. She's looking for concentrations of a blue-green algae that, when it breaks down, releases a dangerous toxin into the water.
“The toxin is in the cell walls of the blue-green algae, and so what happens is when that cell dies, it releases that toxin,” Skopec explained. “We do ankle-deep water, because this is where kids are playing, and so we're most concerned about toddlers in here,” Skopec said, dipping a collection jar into the water.
She takes other samples at knee-deep and waist-deep. She's also measuring wind conditions, because they factor into when and where the blue-green algae blooms appear. Symptoms of contact with the toxin sound like a list of drug side-effects: rashes, liver reactions, nausea, and asthmalike symptoms. Skopec says it can also act as a neurotoxin, possibly causing seizures. The toxin can cause symptoms upon contact with skin, being ingested, and when it's inhaled.
“Because it does essentially get aerosol particles,” Skopec told us, “so then you breathe it in, and you could have asthma or respiratory distress as a result of that.”
Skopec said in lakes with high concentrations of algae, it can form clumps that look like streaks of bright paint. Sometimes, just looking at the color of the water can be a dead giveaway. Water with a green or blue-green cloudiness can be an indicator of the presence of algae.
She says heavy rains earlier this summer washed nitrogen and phosphorus into many lakes, helping the algae grow. She's guessing blooms will show up in more lakes if the warm, still weather keeps up.
“These things can set up quickly, which is why we advise people to just use your eyes.”
For beach monitoring information, you can visit the DNR's website at http://www.iowadnr.gov/Recreation/BeachMonitoring.aspx, or call their hotline at 319-353-2613.