The state has begun the second set of pilot testing alum treatment at Grand Lake St. Marys. A contractor hired by the Ohio Department of Natural Resources began work in the Kozy Marina channel on Tuesday, April 5, and is working at the lake through Friday, April 8.

Three locations have been chosen for treatment. The Kozy Marina channel received a granular alum treatment. A combination treatment of granular sodium carbonate peroxide followed by liquid aluminum sulfate (alum) and sodium aluminate will be applied over two days in Camp Lagoon at the state park. Liquid alum with sodium aluminate will be applied to Windy Point channel.

Each site will be monitored by Ohio EPA staff for six weeks to measure the effectiveness of each treatment in neutralizing phosphorus in the water column. Excess phosphorus in the water feeds blue-green algae that lead to the harmful algal blooms that produce toxins that have the potential to harm humans and animals that contact or ingest it.

Data from this spring’s pilot project will be combined with data from last fall’s research to help the state refine its long-term plan for addressing the internal phosphorous levels in the lake.

The test project should wrap up shortly before a state contractor begins treatment of the whole lake in May. The whole-lake treatment is expected to last approximately 45 days.

Weather conditions may affect the schedule for both the pilot project and whole- lake treatment.