Ambient Engineering was retained by Algonquin to assess two pump station and valve sites located in Dover and in Needham, Massachusetts. The contaminants of concern were hydrocarbons, in particular PAH compounds, contained in condensate and PCBs which were suspect contaminants in the system. The settings of each of the pump stations were isolated woodlands in which the pipeline ran through wetlands. Releases had occurred during operation and maintenance of the pump stations and had been discovered during upgrading of the pipeline capacity.

Ambient investigated both soil and groundwater media to define the nature and extent of releases to the environment. The work was performed as a "Utility Release Abatement Measure" under the Massachusetts Contingency Plan regulations. Since the work was conducted in wetlands or in wetland buffer zones, local Conservation Commission and State Wetland Protection Act regulations guided its performance and subsequent restoration of the site. Soils from different areas were segregated to minimize the volume of soils that might be classified as hazardous. Results showed that soil had been impacted, but that the partitioning of PCBs to soil had protected groundwater from any impact whatsoever.

After testing for compliance with RCRA regulations, certain stockpiles were identified as hazardous waste; these were trucked under Hazardous Waste Manifest to the RCRA licensed disposal facility in Model City, New York. The remainder of the soil stockpiles was found to be minimally impacted and were used as excavation backfill.

Soil tests at the limits of excavation were input to a Risk Characterization, and this assessment showed that Exposure Point Concentrations were an order of magnitude below the S-1 soil standards, indicating suitability even for residential uses.

Each site received a Class A-2 RAO; these are permanent closures which require no deed restrictions for activities or uses in the future.