Toxin Levels Down In Grand Lake

Dr. Stephen Jacquemin gave an update on the lake during August’s Lake Improvement Association meeting on Saturday.
Staff Writer

Microcystin levels in Grand Lake St. Marys are down this year compared to other years but are still extremely high, according to Dr. Stephen Jacquemin an associate professor at Wright State — Lake Campus. 

According to Jacquemin, this summer’s levels are down by 15 to 20 mg/L.

Those numbers are calculated from a water sample that looks at all of the algae that is in that sample. Jacquemin said the results give a sort of worse case scenario. 

“It doesn’t represent the amount of microcystin that you can be exposed to by just running your hand through the water, but it does represent the exposure you have if you just drank the water,” Jacquemin said

The reason those toxin advisories exist is because microcystin is a pretty major toxin and it can cause skin and liver damage. It can affect the body quickly, with people seeing the effects within a day or two and it can also affect the body long term. Acute symptoms include nausea, vomiting, muscle fatigue and general weakness, Jacquemin mentioned. 

He went on to mention that in the past four years, the numbers were trending upward. He made sure to note that this is just one point in the collection of data that they have, but it is different — in a good way — then what they have been seeing. 

“The way you get these things down is by taking the nutrients away from the algae,” Jacquemin said. “The algae require nutrients to feed, the algae require nutrients to grow and if the nutrients aren’t there, the algae counts go down.”

That’s where the focus has been, Jacquemin noted. The treatment trains and the reconstructed wetlands at Prairie Creek, Coldwater Creek and Beaver Creek have been working all summer, removing the nutrients that feed the algae. Jacquemin said that each one of those locations filters about three-fourths of the streams flow this time of year. That number is expected to increase come fall.  Beaver Creek is in its first year of operation and is expected to be able to filter more water in the future also.

“As we approach the end of August and the start of fall, those sorts of values will start to exceed the levels of the stream,” Jacquemin said. “What’s interesting about these reconstructed wetlands that we have all over the watershed is when they are pumping more than what the stream has to offer, they actually dip into the lake, and when they dip into the lake they contribute to the reduction of what is already there.”

For the full story, see Monday's print edition of The Evening Leader.