Monday, August 6th, 2018
Grand Lake toxins seen to decline
Professor: Levels lower this year
By Ed Gebert
CELINA - The amount of microcystins - a type of liver toxin - in Grand Lake has been dropping this year, according to Stephen Jacquemin, Wright State University-Lake Campus associate professor of biology and a research coordinator monitoring the lake.
Elevated levels of microcystins are the reason no-contact warnings have been placed on the lake.
"In the past four years the microcystin levels have trended upwards, this year they are down," Jacquemin told Lake Improvement Association members at their meeting on Saturday. "Are we extremely high? Yes, but we are down quite a bit from last year."
"The way you get these things to go down is taking the nutrients away from the algae," he continued. "The algae require nutrients to feed. The algae require nutrients to grow. If the nutrients aren't there, the algae counts go down. The microcystin counts go down."
The microcystin levels of 70-80 micrograms per liter are still three to four times higher than they should be for the warning signs to be removed, he said. However, this year's levels are about 12-20 micrograms lower than last year's.
Jacquemin credited farmers for their conservation practices and the treatment trains at Prairie Creek, Coldwater Creek and the newest one at Beaver Creek.
"The treatment trains are functioning on all cylinders this summer. They are removing substantial amounts of nutrients that feed that algae," he said.
Jacquemin noted the work of the treatment trains is also helping to improve water clarity. The littoral wetland at the Prairie Creek Treatment Train has about twice the in-water visibility as anywhere else in the lake at 30-40 centimeters, compared with an average of 15 centimeters in the lake.
The Coldwater Creek Treatment Train filters nutrients from about 2-4 million gallons of water each day, and the Beaver Creek Treatment Train filters about 500,000 gallons per day with that amount expected to increase as vegetation in the facility matures, he said.
The Prairie Creek Treatment Train filters about 1 million gallons of water per day, which Jacquemin described as "maxed out." Both he and Lake Restoration Commission Chairman Tom Knapke said they are studying ways to increase capacity at this facility, perhaps to as much as 3 million gallons daily.
Knapke also reported the West Beach project, an ambitious, $500,000 project designed to improve water quality at the beach area so swimming will again be allowed, is still on hold. Ohio History Connection officials, who must sign off before work can begin, have requested a second review of the area near Villa Nova on the northeast corner of the lake, where the beach is located.
The project would extend the rock berm to enclose most of the beach area and install a 50-foot air curtain to help control the flow of water into the beach area. Knapke said he will seek an update on the project early this week.
Ag Solutions Coordinator Theresa Dirksen reported she is working on three projects aimed at filtering nutrients from waterways in Mercer County. One is a $300,000 project to restore about 3,000 feet of the west branch of Beaver Creek as it runs through the Mercer County Elks Golf Course. Reconstructing this area would restore the creek's natural meandering route and increase the habitat and help nutrients to be filtered out by the vegetation. The project will be funded through a state grant.
A second state-funded project will take 17.3 acres of Deerfield Golf Course property in northern Mercer County and convert it into wetlands and upland habitat. Bids will be opened this week on the estimated $74,000 project with construction expected to be concluded by spring.
Dirksen said she is working to acquire a grant for phosphorus reduction and an edge-of-field buffer. She is still working with products designed to take the nutrients out of manure, trying to make the products as efficient and cost-effective for producers as possible.