Blue-green algae was detected Friday at Lake Afton, prompting a warning to lake-goers: Stay out of the water.
Lake Afton, a popular weekend destination about 20 miles west of Wichita, is closed for water contact activities, including swimming and water skiing, according to a statement from Sedgwick County. Pets should also be kept out of the water.
“People should take warnings very seriously,” said Mark Schneegurt, a biology professor at Wichita State with a deep background in the study of cyanobacteria, like blue-green algae.
“Intoxication with these poisons can kill you and your pets,” Schneegurt said. “Some folks will be more sensitive than others, but these are such powerful toxins, that people should stay away from waters with an active cyanobacterial bloom. Over time, as the bloom dies out, the toxins are naturally degraded, and the water will become safe again.”
Ten bodies of water in Kansas were under blue-green-algae warnings Friday. Besides Afton, Atchison County Park Lake, Carbondale West Lake, Central Park Lake (Pond) in Shawnee County, Clarion Woods Park Lake, Jerry Ivey Pond, Melvern Outlet Pond, Melvern Swimming Pond, Rooks County State Fishing Lake and Webster Lake were all under warnings.
Contact with blue-green algae can be harmful, causing skin irritation, stomach cramps, vomiting, nausea, diarrhea, fever, sore throat, headache, muscle and joint pain, blisters of the mouth and liver damage. Swimmers in water containing toxins from blue-green algae may suffer allergic reactions, such as asthma, eye irritation, rashes, and blisters around the mouth and nose, according to the World Health Organization.
Fishing is still permitted at Lake Afton, but anglers wishing to eat their catch should follow Kansas Department of Health and Environment guidelines, the statement said. The guidelines include washing hands and arms and catch with clean, potable water after fishing. Only skinless fillets of fish caught in a lake with blue-green algae should be eaten.
Kate Flavin, a spokeswoman for Sedgwick County, said the Kansas Department of Health and Environment regularly test lakes across Kansas, and earlier this week Afton tested positive for blue-green algae.
What is commonly called blue-green algae is not algae at all — it’s actually a bacteria that can produce fatal toxins.
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Here’s how blue-green algae blooms work, according to Schneegurt.
A population of blue-green algae live in a lake. The bacteria growth is limited by the availability of an energy source — either a limited amount of nitrogen or other nutrients, like soluble iron or phosphorus — in the water.
During the growing season, farmers and homeowners fertilize their crops and lawns, which often place a lot of nitrogen and other energy sources for blue-green algae close to the lake. All it takes is a good rain for these nutrients to flow into the lake, or they can show up through groundwater and runoff.
Once the bacteria have an available energy source, they bloom wildly.
Blue-green algae blooms often look like spilled green paint floating on the surface.
Eventually, the bacteria use up all of the nutrient and start to die, called bloom and bust. Their corpses are eaten by other bacteria, which can grow rapidly and remove oxygen in the water, causing fish to die and the lake to stink.
“There will be signage at all of the entrances and the bait shop and the swimming area and boating docks with warnings, so people will know not to go in the water,” Flavin said.
Flavin said there is staff assigned to the lake, but did not say whether they would be patrolling the area on the weekend.