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Report Finds Little Threat From Spills; Low Concentrations of TCE Identified Around CRREL



Valley News Staff Writer
Sunday, December 17, 2017

Hanover — A detailed report on the ongoing pollution cleanup around the Cold Regions Research and Engineering Laboratory indicates little risk to neighbors along Route 10, including Richmond Middle School and Kendal at Hanover, a retirement community that is planning an expansion close to the federal research center.

Independent analysts hired by the Army Corps of Engineers last year found that a series of chemical spills decades ago had allowed an underground plume of trichloroethylene, a common industrial solvent known as TCE, to pool beneath the 28-acre CRREL site and move toward abutting land.

In a nearly 200-page report released last week, the consultants, Amec Foster Wheeler of London, U.K., said a thorough regime of sampling around the site near the Connecticut River had revealed low concentrations of TCE and, therefore, little risk in areas that neighbors are likely to use.

The EPA in 2011 classified TCE as a human carcinogen, prompting officials at CRREL to accelerate a cleanup of thousands of gallons of chemicals accidentally discharged between 1960 and 1980.

Since then, officials have installed extraction wells to siphon away and treat contaminated water, as well as protective systems to stop gaseous TCE in the underlying soil — also known as “soil gas” — from entering buildings above ground.

“The groundwater plumes do not leave the site or reach the river because they are captured by a series of extraction wells,” reads a two-page summary of the report released this month. “Extracted water is treated and then discharged to the river in accordance with state and federal permits.”

All of these safeguards qualify only as “interim measures,” however, and this study, in addition to another study due in summer 2018, will help Army engineers determine the full extent of the contamination and what, ultimately, to do about it, said Darrell Moore, the Army Corps of Engineers official overseeing the remediation.

In an interview last week, Moore said current cleanup efforts and future safeguards meant there was little to no danger to the site’s neighbors or to the more than 200 people who work at CRREL.

The laboratory, which specializes in studies of sea ice, permafrost and other aspects of cold-weather environments, has not used TCE since 1987. Scientists used the substance as a solvent and a refrigerant in rooms specially chilled for experiments in extreme cold.

A few years ago, federal officials noticed that the plume of chemicals had been nearing the eastern edge of the CRREL property line, drawing closer to Richmond Middle School across the road. Initial tests within the school yielded low readings of TCE gas, which raised concerns among local officials until further analysis revealed that the finding was likely a fluke.

Now, Moore said, the latest investigation has discovered TCE soil gas below the school — but far down, at a depth of about 75 feet. The school building has a vapor barrier built into it that would stop any gaseous contaminants from entering, he said.

Additional sampling just below Richmond’s concrete foundation revealed “very low concentrations” of TCE that were consistent with ambient levels found in nature, Moore said.

“The school really is not at risk,” he said.

Nor, he added, is there risk to potential future residents at a 38-apartment development that Kendal is planning at Rivercrest, a parcel directly north of CRREL that the retirement community is considering buying from Dartmouth College.

“The Army is willing to support any work that’s done there to make sure that no construction workers are put at risk,” Moore said. That support could consist of providing monitoring equipment to make sure no workers are exposed to dangerous chemicals.

Officials from town government, the college, Kendal and the school district said they agreed with Moore’s assessment that TCE posed minimal risk to people on their respective properties.

Jay Badams, superintendent of Hanover-Norwich schools, said district officials had been participating on an advisory board that monitors the cleanup and were “encouraged” by the report’s results.

Badams, citing the report, said TCE at the school “was either not detected at all or was only present at concentrations well below action levels,” and added that more sampling was scheduled to take place at Richmond later this month.

The Hanover Fire Department also has a member on the advisory panel, known as the Remedial Advisory Board. Chief Martin McMillan on Wednesday praised the Army Corps of Engineers for its transparency and concurred that the risk to neighbors was low.

“I’m not overly concerned about the issue right now as far as it impacting people outside the fence line, so to speak,” he said in a telephone interview.

“We are in close and regular contact with CRREL about their TCE remediation efforts,” Justin Anderson, a spokesman for Dartmouth, said in an email Wednesday. “We are pleased that progress is being made. We have no construction plans for the Rivercrest property at this time.”

Kendal officials last week said they had conducted their own testing on the portion of Rivercrest they were thinking of buying and had found no TCE soil gas and no groundwater, another possible means for the contaminant to spread. “We have looked at this extensively and we are confident that we can safely build on the property we are considering,” Kendal spokesman Jeff Roosevelt said in an email.

Early in 2016, Kendal hired Nobis Engineering, of Concord, to assess the possible risk and over the following year the contractors drilled dozens of test wells to ensure the site was safe, Roosevelt said.

Roosevelt added that Kendal planned to include vapor barriers and venting systems under any buildings it may construct, should it decide to buy the parcel. He also noted that any new building at the site would be linked to the town water supply.

Moore said last week the Army Corps of Engineers could receive a forthcoming study about the feasibility of further treatment options as soon as summer 2018.

He declined to say what the research might recommend, other than to note that there are several new remediation technologies under consideration, as well as that such studies usually consider whether any further action is necessary at all.

Rob Wolfe can be reached at rwolfe@vnews.com or at 603-727-3242.