Tidewater MGP Site

GEI was retained by Blackstone Valley Electric Company (now the Narragansett Division of National Grid) and Valley Gas Company to conduct a Remedial Investigation (RI) and Feasibility Study (FS) at a 24-acre site adjacent to the Seekonk River in Pawtucket, Rhode Island. A former manufactured gas plant (MGP) site is located on the property, as well as a power plant and a landfill.

A portion of the property had previously been sold to the city of Pawtucket, which constructed an elementary school and athletic fields on part of the property.

GEI’s scope of work included a soil gas survey around a neighboring elementary school, surface and subsurface soil sampling on the site and the adjoining city of Pawtucket athletic fields and school, test pit excavations, sediment sampling, detailed riverbank inspection, monitoring well installation, and groundwater sampling. GEI also assisted the site owners in developing a public involvement program that included public meetings and current and historical documentation on the site and MGPs.

Following work plan approval by the Rhode Island Department of Environmental Management (RIDEM), field work was initiated to investigate the potential presence of MGP residuals in soil and water at the site. Initially, limited background sampling was performed. The results of the field investigation were documented in a Remedial Investigation report submitted to RIDEM.

An additional background study was later conducted that included collection of more samples from the general vicinity of the site and performance of statistical analyses on the data. Based on the results documented by GEI, a variance was issued by RIDEM for one of the compounds of concern.

A study was also undertaken to identify potential end uses for the site, so that future investigations and subsequent remedial actions could be targeted around the potential future uses of the property. GEI provided input as to the impacts of the environmental concerns on potential future site uses.

In addition, GEI performed probability-based cost estimating for the environmental management of the site.