TRAVERSE CITY — A groundwater plume contaminated with cyanide runs right to the edge of, but is not polluting Grand Traverse Bay, according to a new scientific report.
“It’s close,” said Doug Kilmer, a senior geologist with AKT Peerless, which performed tests on a cyanide-tainted groundwater plume beneath the city’s Warehouse District and adjacent to Grandview Parkway. “We are not detecting (cyanide) in the bay.”
High levels of cyanide found in groundwater at the Hotel Indigo construction site this summer prompted an extensive scientific probe into whether cyanide is leaching into the bay. Measurements of cyanide in groundwater at the Indigo site along Grandview Parkway measured as high as 1,200 parts per billion this summer, well above levels that would allow the water to be discharged to the city wastewater treatment plant.
The findings raised concerns about future development in the Warehouse District, as well as questisn about the bay’s long-term health. The Grand Traverse County Brownfield Authority commissioned a scientific study on the groundwater, and hired AKT Peerless.
Company officials closely worked with the Michigan Department of Environmental Quality to draw new water samples and review historical water tests in the area.
Kilmer said Wednesday the study shows cyanide-contaminated water runs right to the edge of Grand Traverse Bay. But tests performed by Peerless on water directly beneath the bay showed no harmful levels of cyanide.
“It hasn’t migrated or spread that far,” Kilmer said. “We are just not seeing it. The plume is probably actually diminishing in size over time.”
The findings prompted a collective sigh of relief from local economic development officials and politicians Wednesday.
“Great news,” said Mark Eckhoff, who sits on the Brownfield Development Authority.
One environmental consultant warned that the issue is far from over. The fact that cyanide is found in water samples so close to the bay still presents a significant threat to the bay’s aquatic health, said Chris Grobbel.
“This is typically what happens when a groundwater plume enters into a large body of water like the bay,” Grobbel said. “The volume of water in the bay is so great, with currents, that it’s hard to monitor it as it gets into the water.”
“They’ve got (excesses) right near the venting point,” Grobbel said, adding that he expects the DEQ will continue to monitor the situation, given the test results.
“They are likely going to require them to insure toxic concentrations aren’t going into the bay,” Grobbel said. “It’s close, and that’s enough.”
Speculation as to the cyanide’s source centers on an old coal gasification plant that operated for decades across the street from the Hotel Indigo construction site. The current property owners, the Michigan Gas Utilities Corporation, deny the coal gasification plant is the source.
Kilmer said the AKT Peerless study did not seek to pinpoint the toxin’s source. He said tests show the cyanide’s central location is right at the Hotel Indigo site, but that the project is helping with remediation. Cyanide-contaminated soils have been dug up and removed. Groundwater pumping at the site also prompted cyanide levels found in groundwater at the site to diminish significantly.
“They are pumping out the core of it and it’s thinning out,” Kilmer said of the contaminated groundwater. “The soil containing cyanide at Indigo was removed. We think that’s going to go a long way in keeping the levels down.”