Toxin count lowest in seven years

CELINA - Despite earlier fears that excessive rains would mean a setback for Grand Lake cleanup efforts, Dr. Stephen Jacquemin of Wright State University-Lake Campus has reported that microcystin levels in Grand Lake have reached a seven-year low.

"We've got seasonal fluctuation, but microcystin levels in the lake are among the lowest they've been since 2011, 2012," he told the newspaper. "We have a lot of work to still be done, but it's possible, and it's worth it."

Microcystins are an algal toxin that can harm the liver, cause gastrointestinal symptoms and rashes and can sicken people and kill small animals. Phosphorus-fed toxic blue-green algal blooms have resulted in state-issued water advisories on Grand Lake every year since 2009. The local watershed is the only one in the state designated as distressed due to unsafe algal toxin levels, a designation the watershed received in January 2011 after animals and humans were sickened by the toxins in Grand Lake in 2010.

A recent graphic he created, which was released by the Lake Improvement Association, shows microcystin levels trending upward in 2010 and 2011. The graphic shows microcystin levels reached a peak about three-four years ago and have been dropping ever since.

Jacquemin credits the improvement to the multiple water-quality improvement initiatives that have been rolled out.

"Lots and lots of water-quality initiatives and lots and lots of water-quality practices have been put into the watershed over the last decade and reducing the nutrient load going into the lake."

Excess nutrient runoff helps feed the blue-green algae that produces microcystin. Studies show that phosphorus found in manure is the nutrient that most contributes to algae growth in the 13,500-acre recreational lake and that most of the runoff comes from agricultural land, the biggest land use in the 58,000-acre, livestock-heavy watershed located in Mercer and Auglaize counties.

Landscape improvements, including the construction of man-made wetlands and littoral zones, help absorb some nutrient runoff. Jacquemin said they have been among the biggest factors of success.

"Wetlands are among the biggest pieces of that, but it's also a whole litany of other things going on, things like cover crops and water-control structures and increasing (littoral) buffer areas, that sort of stuff."

With excessive rains and severe flooding from earlier in the year, many had predicted algal blooms would be more severe this summer due to a larger amount of nutrient runoff. Jacquemin said that once the summer is over, data from the entire season would need to be analyzed to know for sure why the lake has seen no huge impact from the earlier rains. However, he said he and several others share a theory.

While some nutrients were definitely washed into the watershed after the flooding events, the damage likely was not as severe as predicted because farmers hadn't been able to apply fertilizers to their fields.

The wet weather prevented many farmers from working or planting in their fields, so the heavy rains were likely too early to wash applied nutrients away, he said.

"We'll know more in the fall," he concluded.