The Carlisle Mosquito Online

Friday, February 1, 2002


Groundwater at police station needs less testing

After over ten years of cleanup and water quality testing, the Carlisle Board of Selectmen decided at their January 22 meeting that groundwater at the police station was now clean enough to warrant reducing the frequency of testing. This action may save the town a couple of thousand dollars annually.

After water contamination was discovered near the police station in the 1980s, the town began a treatment program to remove petroleum pollutants, including benzene, ethylbenzene and xylenes. Active treatment was discontinued in 2000, but the town has continued to monitor the surface and groundwater, while the small amount of residual pollution dissipates. Once the pollution drops enough to meet the state department of environmental protection's (DEP) qualifications, the town can submit a Class A Response Action Outcome (RAO) Statement, and effectively close the case.

The town's consultants, ENSR International, summarized their findings in a letter written in September 2001 to town administrator Madonna McKenzie. Petroleum concentrations in the groundwater remain too high to allow application for a Class A RAO. However, ENSR recommended that the groundwater treatment program "remain shut down at this time based on the asymptotic levels" of pollution that remain. ENSR described two options for the town:

· Continued semi-annual groundwater monitoring at an annual cost of $3,500 to $4,000.

· File a Class C RAO with the DEP, and monitor petroleum pollutants in the groundwater at the site once every five years. This would cost about $2500 to prepare the Class C RAO filing, and then about $2000 every five years for the water testing. Once residual pollution levels were smaller, the town could then file for a permanent Class A RAO.

As a cost-cutting measure, the selectmen voted to file a Class C RAO and reduce the amount of water monitoring. The selectmen agreed that a Class C RAO would not prevent them from changing their minds and testing the water more frequently in the future, if there were ever any concerns.

According to board of health agent Linda Fantasia, who was reached by phone later, the pollution from the former filling station across the street does not appear to be traveling toward the police station site. However, the water quality subcommittee had recommended continuing the semi-annual water monitoring for at least one additional year. The board of health has not had a chance to discuss the selectmen's action.

2002 The Carlisle Mosquito