Posted on July 23, 2018
By Glenn Coin, syracuse.com
Onondaga Lake is recovering faster than expected after dredging and capping were completed over the past few years, a Honeywell subcontractor said today.
Mark Arrigo, project manager for Parsons, said today the sediments flowing in from tributaries are cleaner and are covering the lake bottom at a higher rate than anticipated.
“All indications are it’s progressing faster than expected,” Arrigo told the Onondaga County Environmental Health Council. “We’re close to meeting goals in all areas of the lake.”
The Environmental Protection Agency said basically the same thing in 2015, when it reviewed the cleanup and found it progressing faster than planned. Mercury levels in the water and in zooplankton, the tiny creatures that form the base of the lake’s food chain, were lower than anticipated, the EPA said.
Starting in 2012, Honeywell dredged 2.2 million cubic yards of contaminated lake bottom and dumped it in a landfill in Camillus. The company also covered 475 acres of the lake bottom with 3 million cubic yards of sand mixture to lock in portions of the sediments that still hold high levels of mercury and other chemicals. The state Department of Environmental Conservation just approved Honeywell’s long-term monitoring plan of the clean up.
The cleanup also includes “natural recovery,” the natural deposit of sand, organic material and other sediments that flow into the lake from tributaries such as Nine Mile and Onondaga creeks.
Since 2009, Arrigo told the council, 3 inches of new, clean sediment has covered the deep basin in the southern part of the lake, much of which was not capped.
Honeywell put fluorescent microbeads at nine locations in the lake in 2009 to provide a marker. Every three years, workers take a core sample at those locations and see how deep the beads are below the surface of the accumulated sediment.
There’s no worry that the sediment will eventually fill the lake, Arrigo said.
“The lake is deep enough that even at the current accumulation rate, there won’t be any recreational impact as long as anyone here is around,” he said.
Travis Glazier, Onondaga County’s director of environment, said there were fears in the ’90s that the lake would fill up with sediment in a few decades, but later studies showed that wouldn’t happen.
He noted that there are studies underway to help control the amount of sand from the mud boils in Tully that are carried into the lake by Onondaga Creek. An estimated 20 tons of sand and silt are carried into the lake every day.
Craig Milburn, a consultant for Honeywell, said the company is committed to the cleanup requirements established by the state, and could be monitoring the lake for “a very, very long time.”
Milburn said the cleanup has made tremendous progress.
“Ten to 15 years ago a lot of people thought, ‘never in my lifetime,’ and now we’re planning for how we’re going to use a clean lake,” he said.
Source: syracuse.com
