Chlorinated Solvent Assessment

SCOPE OF WORK: Site assessment, sub-slab depressurization system design, and LSP services

Omni Environmental Group is providing environmental consulting and Licensed Site Professional (LSP) services to a law firm representing a commercial property owner following the identification of Recognized Environmental Conditions (specifically trichloroethylene (TCE) and other chlorinated compounds in groundwater) during a Phase II Environmental Site Assessment to support the potential sale of the property.

Omni Environmental Group has conducted assessment activities including test pits, soil borings, overburden monitoring wells, bedrock fracture trace analysis, bedrock monitoring wells, soil gas points, grid pattern soil gas screening, and the analysis of soil, groundwater, soil gas, and indoor air samples. The resulting conceptual site model suggests that TCE was likely discharged to the subsurface via a dry well or drain system, and has since migrated 400 feet in groundwater from the suspected source area. The contaminated area includes portions of an adjacent commercial property and an abutting street.

Regulatory submissions to the Massachusetts Department of Environmental Protection (MassDEP) have included the initial 120-day Release Notification Form; notification for a threat of an Imminent Hazard (IH) Condition; and a Phase I Initial Site Investigation prepared in accordance with the Massachusetts Contingency Plan (MCP).

Omni Environmental Group has provided human health risk assessment for TCE which included the collection and evaluation of soil gas and indoor air samples collected from the site building and the adjacent commercial building.

Other services anticipated for this project include the installation of additional overburden monitoring wells within the abutting street; continued assessment and media sampling as part of the Phase II Comprehensive Site Assessment; assessment, design, and installation of a sub-slab depressurization (SSD) system for the site building; filing of an Activity and Use Limitation and regulatory submittals with MassDEP to demonstrate a level of No Significant Risk in accordance with the MCP.