MGP Site Assessment and Remediation at Public Playground/Residential Site

GEI has conducted MCP investigation and remedial activities at a former manufactured gas plant (MGP) property in Massachusetts, on behalf of Massachusetts Electric Company. The former MGP occupied two parcels: a 7.5 acre parcel which includes a children’s playground, baseball field, basketball and tennis courts, and a wetlands area; and an adjacent 2.1 acre residential property.

Contaminants attributable to the historic MGP are present in surface and subsurface soil, sediments, surface water, and groundwater. The site is classified Tier 1 based on the results of a Phase I investigation. The site is located within 100 feet of a river and is actively used for recreation and as a residence.

During the investigation and subsequent work, GEI played a significant role in maintaining positive public relations with City residents and officials. GEI participated in numerous meetings with City officials and local residents to discuss proposed activities and results of investigations.

GEI conducted a Release Abatement Measure (RAM) to remove contaminated soil from the upper 3 feet in the playground. The excavated soil was transported for off-site treatment and disposal and the excavation was backfilled with clean fill. The playground was reconstructed following the earthwork. A second RAM was also conducted to remove semi-solid tar blobs from the banks of the stream on the residential property.

GEI completed three Immediate Response Actions (IRAs) at the site. The first IRA addressed the detection of elevated BTEX concentrations in groundwater near the residence. GEI used indoor air sampling results to document that groundwater contamination had not affected the air inside the residence. The second IRA was required because low concentrations of cyanide were detected in surface water on the property, representing a potential substantial release migration (SRM) condition. GEI conducted an evaluation of the source and extent of the cyanide and will address the condition during the Phase III investigation. The third IRA addresses toluene detected in indoor air in a downgradient residence.

GEI is currently conducting a Phase II investigation, which includes additional soil, groundwater, sediment and surface water sampling to support ecological evaluations of the on-site pond and stream, and the river. GEI is using forensic analysis to evaluate the source of PAHs detected in the sediment from the river.