COLUMBUS, Ohio (AP) — A test treatment has not been completely effective against a cause of the toxic algae that led to warnings and a decline in tourism at a major Ohio lake this summer.
Aluminum sulfate, or alum, spread over test areas appeared to have no impact on phosphorous at one site in Grand Lake St. Marys, The Columbus Dispatch reported Friday. The phosphorous levels in the water were reduced by 50 to 60 percent at two other sites.
Grand Lake St. Marys, situated between Celina and St. Marys in western Ohio, is one of the state’s most polluted lakes because of run-off of manure and fertilizer from nearby farms. Phosphorous is found in manure and chemical fertilizers and fosters the harmful blue-green algae.
The 13,000-acre lake is used for recreation and drinking water. Its watershed covers more than 59,000 acres.
A report by environmental consultant Tetra Tech Inc. said the alum should have more significantly lowered the phosphorus levels at all three sites. It recommended more testing in the spring.
The Ohio Environmental Protection Agency released the treatment findings Thursday. Officials from the agency and the Ohio Department of Natural Resources told the Dispatch they want to meet next week on the findings before deciding what to do next.
Grand Lake area residents such as Milt Miller are hoping for stronger improvements in the lake before the summer.
‘‘We simply have to find a short-term fix that brings our economy back,’’ Miller, a banker and co-founder of the Grand Lake St. Marys Restoration Commission, told the newspaper.
Ohio regulators have sought to restrict some farmers from spreading manure on frozen land to prevent it from running off into the state’s largest inland lake. A legislative committee recently cleared the way for the new rules.