Client Successes

Case Study - Phase IV NAPL

A release of approximately 4,700-gallons of non-aqueous phase liquid (NAPL) from a punctured gasoline product line was discovered at the site and approximately 3,320-gallons of NAPL was recovered during emergency response (ER) activities conducted under the supervision of the Massachusetts Department of Environmental Protection (MA DEP).

The purpose of the Phase IV As-Built Construction, Final Inspection, and Completion Statement are to verify that the Comprehensive Remedial Actions outlined in the Phase IV Remedy Implementation Plan (RIP) have been implemented. CEA presented this report, which has been prepared pursuant to 310 CMR 40.0878 of the Massachusetts Contingency Plan (MCP).

The MA DEP was notified of the presence of NAPL in monitoring wells. An Immediate Response Action (IRA) Plan was submitted to address the NAPL discovery and reduce the potential for vapor migration. Soil vapor extraction was initiated to abate potential development of an Imminent Hazard (IH) condition at the site. An IRA Completion report was submitted. A Phase I Limited Site Investigation report and Tier Classification was submitted to the MA DEP and the site was classified as Tier II.

A Release Abatement Measure (RAM) Plan was submitted for the installation of a soil vapor extraction (SVE) and off-gas treatment system and installed. The RAM Completion report was submitted.

A Phase II Comprehensive Site Assessment report was submitted to MA DEP and an Addendum to the Phase II was submitted to address the installation of off-site monitoring wells that were not installed prior to the Phase II submittal. The Addendum also included the IH Evaluation of indoor air quality at the Fire Department (FD) located across the street on the northeast of the site. The IH Evaluation determined that an imminent hazard condition did not exist.

A Phase III Remedial Action Plan (RAP) was submitted to MA DEP. A pilot test for Enhanced Fluid Recovery (EFR)/high vacuum extraction was conducted as part of Phase III activities. However, EFR was determined not to be an effective remedy to reduce hydrocarbons in the source area. The addition of oxygen releasing compounds (ORC) to specified monitoring wells was selected as a primary source area for reduction measures. In a Phase IV Remedial Implementation Plan (RIP) was submitted to MA DEP. Groundwater samples were collected from monitoring wells and the basement sump in the LFD to evaluate the effectiveness of the Oxygen Releasing Compounds (ORC) socks. All samples were submitted to a state-certified-laboratory and analyzed for volatile applicable Method I standards. Analytical results indicate that significant reductions in overall concentrations of gasoline constituents have occurred onsite since the initial release. Slight increases of MTBE occurred in two wells during the most recent sampling events; however, all VPH aromatic and aliphatic hydrocarbons and target analytes (including MTBE) are currently below applicable MCP standards in all monitoring wells. Concentrations of MTBE in groundwater collected from the FD basement sump have increased from 327 ug/l in July to 1,100 ug/l in January. Concentrations are currently below GW-2/GW-3 standards. A groundwater treatment system has been installed to treat groundwater prior to its discharge to a drainage ditch behind the FD.

Comprehensive Remedial Actions conducted at the subject location have been performed in accordance with the rules and regulations stipulated within 310 CMR 40.0870 and 40.0872. All activities were conducted under the supervision of a Licensed Site Professional in accordance with the MA DEP. Comprehensive Remedial Actions will be continued under Phase V Operation, Maintenance and Monitoring (OMM) until the requirements of a Class C Response Action Outcome (RAO) have been met.