Grand Lake St. Marys once again is the site of an experiment that state officials hope will help keep toxic algae at bay this summer.
Ohio Department of Natural Resources officials were at the 13,000-acre lake in western Ohio yesterday to watch employees of HAB Aquatics Solutions spread hydrogen peroxide across a channel near the state park’s campgrounds.
The company, based in Lincoln, Neb., will return there today to spray aluminum nitrate, or alum, in hopes of robbing the lake of phosphorus, which feeds algae.
The state plans to spray about 3.3 million gallons of alum on most of the lake starting in mid-May.
"This demonstration will develop information that will help make the summer project more effective," said Scott Fletcher, operations manager for Ohio’s state parks.
Fletcher won’t say that the alum treatments will rid the lake of algae. The state, he said, hopes it will keep the algae from becoming a health threat.
"I don’t want people to think that by making this application that we won’t have any blue-green algae in the lake," Fletcher said. "We’re optimistic this treatment will reduce the frequency and severity of the blooms."
Also called cyanobacteria, blue-green algae are common in most Ohio lakes and streams. They grow thick in water polluted with phosphorus, which can come from manure, fertilizers and sewage.
Fed by manure that rains wash off nearby farms, algae grew so thick at Grand Lake St. Marys last year that the state warned people not to touch the water, take boats onto the lake or eat fish they caught there.
It was the second year that algae had plagued Grand Lake. Last year, 20 public ponds and lakes in Ohio were plagued by toxic algae.
The Grand Lake St. Marys warnings torpedoed the local tourism economy. In September, state health officials said algae-produced liver and nerve toxins probably caused seven people to get sick.
The state ran a first round of alum tests at the lake in the fall, but the results were disappointing. The chemical reduced phosphorus in lake water by 50 to 60 percent at two tests sites and appeared to have no effect at a third.
The hope is that the hydrogen peroxide will help increase the alum’s effectiveness. The Ohio Environmental Protection Agency will take samples and run lab tests over the next six weeks to weigh the results, said spokeswoman Dina Pierce.
The Ohio EPA provided the $51,521 for this week’s chemical applications and will provide the $5 million for the lake spraying this summer.
Past estimates say it would cost $8 million to treat the entire lake. Fletcher said the state will concentrate efforts on a central 5,000-acre zone where tests detected the highest levels of phosphorus in mud on the lake bottom.
Milton Miller, co-founder of the Grand Lake St. Marys Restoration Commission, said he’s hopeful the strategy will work and that tourists will return.
"The reality is, the state doesn’t have that much money," Miller said. "We’re trying to get the best bang for $5 million."
By Spencer Hunt, The Columbus Dispatch