ST. MARYS — Rising toxin levels in Grand Lake St. Marys have prompted state officials to issue stronger warnings, even against boating in the lake.
The Ohio Environmental Protection Agency, along with the state departments of health and natural resources issued fresh warnings Friday telling people to stay out of the water and avoid boating and eating fish from Grand Lake. They also advise against allowing animals to drink from the lake.
High levels of nerve and liver toxins earlier in the season prompted the state agencies to issue warnings against swimming in the water. But the latest round of testing has shown microcystin levels well beyond anything found in the past.
“The microcystin levels that we got back from our sampling this week are very, very high. To put in perspective, last year we saw the highest levels at 82 parts per billion. This year, last week was the highest we had seen at over 250 parts per billion. This week… it was over 2,000,” said OEPA Spokeswoman Dina Pierce.
The state agencies have been monitoring Grand Lake since an early season bloom of blue-green algae began taking over the lake earlier this year. The algae — actually a bacteria called cyanobacteria — is fed by nitrogen and phosphates, most of which runs into the lake from the manure of millions of farm animals raised in the lake’s watershed. Warm weather and the absence of rain in recent weeks have sped the growth, Pierce said.
“Weather has a lot to do with it. We have had a few storms but essentially the weather’s been very hot and relatively calm, so the weather has been perfect for the algae to grow,” Pierce said.
The EPA had said it was OK to boat and eat fish from the lake, as long as the fish were filleted and had the skin removed. But the new levels make even that questionable.
“In the past, we said if you discard skin, fat and organs and stick with the fillets it was probably OK. That may still be accurate, but studies have not been done on lakes with levels of microcystin this high. We just don’t know,” Pierce said.
Celina’s treated drinking water is tested regularly and remains free of algal toxins.