The extended heat wave has helped foster the growth of dangerous blue-green algae in lakes and ponds in Kansas, threatening boaters and swimmers.
The Kansas Department of Health and Environment on Friday issued warnings telling visitors at five lakes around the state to avoid contact with the water.
The warnings were issued for Milford Lake near Junction City; Santa Fe Lake in Augusta; Marion County Lake; Memorial Park Lake in Great Bend; and Meade State Lake.
Blue-green algae are bacteria that produce harmful toxins. The algae flourish in warm, stagnant, sunlit water. The current heat wave combined with drought have aggravated the problem, officials said.
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High levels of the algae can cause intestinal, respiratory or skin problems.
"We anticipated we wouldn't see it getting like this until we were three weeks further in," said Tom Langer, bureau director for environmental health with the KDHE. "We've had a heat wave, so it's come a little bit sooner than normal."
"It's lasted about 14 days," he said, "and we don't see that mitigating anytime soon."
Rod Davis, caretaker at Santa Fe Lake, said he hadn't been notified of the algae warning. Fish have been dying there, he said, but that has been due to lack of oxygen from low water caused by drought.
Miranda Myrick, KDHE spokeswoman, said the department's bureau of environmental field services tested the water at Santa Fe Lake early in the week and confirmed the results.
"We know the water's not up enough for recreation, but it is a body of water, so were putting the message out to the public that there is a potential risk for anyone coming in contact with the water that is in the lake," she said.
The lakes under KDHE algae warnings aren't closed, but the department recommends that visitors to those lakes don't drink the water; avoid swimming, wading or other activities that result in full body contact with the water; clean fish well, eating only the fillet portion and discarding all other parts; and keep pets from contact with, or drinking, the lake water.
At Milford Lake, two boat ramps and two swimming beaches were closed, officials said. The parks, marinas and lakeside businesses around Milford Lake remained open, including camping and other recreational activities. The drinking water and showers are safe and not affected by the algae.
The KDHE also issued advisories for five other lakes — Big Hill Reservoir near Cherryvale, Perry Lake northeast of Topeka, Marion Reservoir, Old Herington City Lake, and Logan City Lake in Phillips County.
Advisories indicate that a hazardous condition exists, according to the KDHE. Water activities like boating and fishing may be safe, but direct contact with water is strongly discouraged for people and pets.
The algae feed on nutrients such as nitrogen and phosphorous that flow into the lakes from industrial discharge, excess fertilizer and natural soil erosion and runoff, officials said.
Without rain, lakes can't get flushed, and portions dry up, leaving stagnant pools ideal for algae growth.
Ron Kaufman, director of information services for the Kansas Department of Wildlife, Parks and Tourism, said the algae problem has had an effect on tourism, but it was hard to tell how much because it has coincided with the high temperatures.
"For our facilities, it does affect the people who wanted to come and swim, and stay in our campgrounds and cabins," he said.
At Santa Fe Lake, there haven't been many visitors all year, but that's because of drought, said Davis, the lake's caretaker.
"There's not enough water. You can barely put a kayak in," he said.
Risk to livestock
Because algae thrive in stagnant water, they can be a particular problem for farm ponds used to water cattle, said David Cantrell of the Pittsburg County Oklahoma Cooperative Extension Service.
"Under normal conditions, the organisms are... suspended in the water, but as they multiply rapidly, large numbers of dead organisms float to the surface," Cantrell said. "Problems occur when livestock consume water from the bloom area."
Toxins from the algae affect the cattle's nervous system and liver, resulting in weakness, muscle tremors, convulsions and even death. Cantrell said ranchers should check ponds for blooms, fence off downwind drinking areas, and switch to alternative water sources when temperatures rise and blooms are spotted.
Langer, of the KDHE, said water management has a lot to do with the blue-green algae bloom.
"This is something that has really been a long time getting to his point, because historically what we've seen is our lakes are getting a little bit older, and some are getting shallower, making nutrients more available," he said.
"How do we make it go away? That is a question that is going to take time and a lot of effort by everyone in our state," Langer said.
"Everything we do 365 days of the year affects our water."