Source: http://www.thehour.com, October 12, 2016
By: Emilie Munson
Five years after the discovery of PCBs and other contaminants in the ground at Greenwich High School, much remediation work has been completed, but a long and expensive path to clean soil remains.
With no timeline for finishing in sight, Greenwich’s Public Works Director Amy Siebert said she estimates the town could spend around $14 million more to clean up the toxins permeating the high school’s property. She cautioned costs could go higher, however, and even range up to $20 million.
“All those project costs are going to be dependent on when we get to (remediation), exactly what we end up having to do,” she said. “Ideally, if the world were great, maybe it would come out to be a little less because we’ve done some work in the western parking lot already, but we can’t predict it will be less.”
Construction crews first discovered the contaminants in July 2011, shortly after beginning work on the high school’s $44 million Musical Instruction Space and Auditorium complex.
The town’s cleanup plan was approved by state and federal environmental agencies in November 2013, and since that time, work has been twofold — simultaneously testing and remediating the soil, while keeping tabs on the groundwater below.
Soil work began in 2014, and after two years of efforts to remove PCBS and other toxins from the property, all fields and paths at GHS are open, an environmental testing update released by the district and town of Greenwich last week announced.
Soil remediation has been completed on the south side of Greenwich High’s campus, in the vicinity of Cardinal Stadium, Siebert said.
But some areas between the west parking lot and athletic fields three and four still require remediation and remain fenced off.
“These areas will remain inaccessible to the general public until the final sitewide remediation is complete,” the update said.
Other areas around fields two, three and four are not fenced off, but need remediation. Toxins in these areas are deep enough that they do not pose a risk to people using the fields for typical recreation, according to officials, but they will be removed so the areas are safe for maintenance staff who might dig to address irrigation issues.
Cleanup will include the excavation and off-site disposal of between one and three feet of impacted soil from these areas.
“We try to be careful and conservative, as does the town, and really just try to be protective of human health and the environment,“ said Mike Doherty, vice president of AECOM, an environmental consulting firm, and program manager for the project.
When cleanup for these areas will begin is not clear. For now, town officials are waiting for approval of their remedial action plan to come from state agencies.
“We have ongoing work that we are doing to answer some of their questions,” said Siebert. “One cannot dictate that timeline. The folks in Hartford are very busy. We are not the only project in the state of Connecticut.”
Remediation projects lasting more than four years are typical, Siebert said.
The remediation of Cos Cob Park took over a decade, Doherty said.
For now, the town can continue its groundwater monitoring, which it began in February 2012. Scientists test the groundwater quarterly using a network of 29 monitoring wells installed at the site.
“We’ll monitor for PCBs, metals, some semi-volatile organics. There’s a variety,” Doherty said. “We found PCBs in a couple of monitoring wells.”
Monitoring tests continue to show the contaminated water is not migrating out of the GHS footprint, officials said. That’s because the soil that the groundwater moves through has trapped the metal-based contaminants.
“You can think of the soil, or the material underneath there, as kind of like a sponge,” said Siebert. “You know that you can flow water through a sponge. You know that you can get coffee grounds in your sponge and water will still flow through it, but the coffee grounds have a tendency to sort of stay put in there.”
Groundwater testing will continue throughout the year and into summer 2017 to monitor for possible migration.
Contaminants in the groundwater are not threatening drinking water. Aquarion Water Company provides potable water to the high school and all residences in proximity to the site.
Siebert urged the public to remain patient with remediation.
“This is nothing new. How to sample soil and characterize soil is a standard process, and you just go through these things in a step-wise fashion,” she said. “I think it can be frustrating for the public because everyone wants answers right away.”