Although microscopic blue-green algae organisms are natural, common bacteria in many Kansas waterways, toxic blue-green algae (cyanobacteria) are a growing problem. The blooms were found in 11 lakes across the state, by fall 2023. Six lakes received warning status while five were at the ‘watch’ level.
Toxic blooms may discolor water or produce scum on the surface, rocks, shoreline, and watery depths, and wind can blow these algae into other areas of the water. The Kansas Department of Health and Environment has discouraged skin contact and allowing pets to eat dried algae, which may expose humans and animals to health risks such as rashes, vomiting, a sore throat, or a headache.
In Overland Park, Kan., the small South Lake, received warning status. Hoping to help combat toxic overgrowth, the city has installed floating wetlands in the lake. But untangling problems associated with blue-green algae is challenging, says Ted D. Harris, BSc, MS, PhD, assistant research professor at the Kansas Biological Survey & Center for Ecological Research at the University of Kansas.
“Blue green algae are technically available everywhere,” Harris says. “Toxic blue-green algae blooms may increase with higher temperatures, calmer wind days, and increased nutrients like nitrogen and phosphorus that run off home lawns and farm fields.
“Recent research has shown that toxins may be highest at water temperatures between 68 and 77 degrees. Blooms that form in spring or fall could contain the highest levels of toxins, but toxic blooms can still occur in the summer. “If you see a “paint spill” like scum in a pond, please keep your pets and yourself away.”
Such algae may also produce taste and odor compounds resembling musty earth. And Harris says the cost of creating drinkable water may as much as double to improve this condition, while compromising public confidence in the water supply.
He also says Kansas has a somewhat puzzling higher concentration of larger, more intense toxic blooms than surrounding states do. “It seems like this is becoming more prevalent. There seems to be more phosphorus in our systems, with increased blooms, and we think a lot comes from the water itself.
“Some people introduce zooplankton and largemouth bass [to affected waterways]. But with so many nutrients, there’s only so much the food web can do. In Kansas we do have a lot of wind, which can help decrease blue-green algae by mixing the lake water.
“We need long-term nutrient control from the watershed. There are chemicals we can use to decrease nutrients and algae, although most are very expensive. Hydrogen peroxide may be economically feasible against scum. But changes we make now won’t have an immediate effect. It might take decades.”
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ADDITIONAL SOURCES:
11 Kansas Lakes Impacted by Blue-Green Algae
https://fox4kc.com/health/blue-green-algae-warning-in-effect-for-johnson-county-lake/ (Sept. 2023)
The truth about toxic algae: How you can help combat this public health issue
Harmful Blue-Green Algae: Frequently Asked Questions
https://www.health.ny.gov/environmental/water/drinking/bluegreenalgae/faq.htm