Grand Lake will remain open to boating this weekend, but the public is strongly warned to avoid personal bodily contact with the water. Swimming, skiing, and use of personal watercraft are all discouraged due to the unprecedented outbreak of potentially toxic blue-green algae in Grand Lake.
According to GRDA Director of Ecosystems Management Dr. Darrell Townsend, representatives from the Department of Environmental Quality, and scientists with the Corps of Engineers, this is the largest outbreak of blue-green algae in the state’s history. The algae is known to be toxic to humans, especially children, and animals.
“This is different from any outbreak we’ve ever seen before,” Townsend said. “With the weather conditions we’ve had, this has spread rapidly. We think we may be just beginning to deal with this.”
Samples of lake water were taken on Tuesday, and send off to a lab in Florida for testing. The results from samples taken from Horse Creek came back with a toxin level over twice the acceptable limits established by the World Health Organization for water safety.
Children are especially at risk from contact with the algae, which can cause skin rash, irritations of the eyes nose and throat, and respiratory infection. Animals that swim in contaminated water and ingest the algae have been reported to die within an hour in some cases.
The board stopped short of banning swimming in the lake, but GRDA Lake Patrols will be making boaters and swimmers aware of the algae problem, and encouraging them to remain out of the water, and to be on the lookout for areas of algae in the water.
The worst areas of concentration are currently in the Duck Creek and Horse Creek areas, but high temperatures and relatively still days are causing the algae to reproduce rapidly and spread throughout the lake.
Officials said there is no practical remedy for the algae except to let the blooming cycle run its course. The algae is most toxic as the bloom dies, and the toxins are released. It is expected that as the algae dies and settles, marine life in the lake will be affected.
“We think the next step will be a large fish kill,” Townsend said. “There will be a large toxin release, and the decay of the algae will suck a lot of oxygen out of the water.”
According to Dr. Tony Clyde of the Corps of Engineers, the recent conditions of flooding, followed by periods of record heat and bright sunlight have provided an ideal breeding ground for the algae. Flooding fills the lake with nitrogen and phosphorous, which the algae feed on, and high temperatures and direct sunlight are a catalyst for algae reproduction.
“There is no practical treatment for the algae but to let it run its course,” Clyde said. When it runs out of nutrients and light it will die. The only real treatment involves the use of large amounts of copper sulphate, and that would have more serious effects long-term.”
GRDA Board members were very sensitive to the economic concerns of possibly closing the lake, but still sensitive to health concerns of people using the lake, and strongly urged them to use caution.
“We want to stress that this is not Armageddon, the lake is not dead,” board member Greg Grodhaus said. “This is a temporary situation and it will get back to normal. But we need to urge everyone to use caution, and common sense around the lake right now.”