Old Southington Landfill

Superfund Site Remediation (1993 – Ongoing)

The Southington Superfund site is a closed, sanitary landfill covering eleven acres in Southington, Connecticut. The site was in operation from 1920 to 1967 and, since its closing, several commercial businesses and private residences had been built on the property.

In 1993, MACTEC completed a Remedial Investigation / Feasibility Study (RI/FS) of the site involving groundwater, surface water sediment, soil, air, methane measurement and control, ecological assessments, and human health risk assessment. Shortly thereafter, the Performing Settling Defendants (PSDs) obtained an interim Record of Decision to cap the landfill. After a settlement was reached in 1998 with 268 responsible parties, work promptly began to relocate all businesses and residents located on the site, cap the landfill, extract any hazardous gases, and conduct groundwater studies.

While construction of the synthetic cap was completed in 2001, groundwater investigations continue with a special focus on downgradient plume definition involving chlorinated ethenes. Following completion of sufficient data collection, MACTEC will conduct an Amended Feasibility Study for groundwater.

MACTEC’s other roles included assisting with State and EPA negotiations, community involvement, development of work plans and major deliverables, cost-estimation and control, and coordination of a multimedia technical team. Using information obtained and interpreted during the RI/FS, MACTEC helped attorneys develop litigation strategies for two lawsuits filed against the PSDs. MACTEC also provided expert witness testimony involving types of waste disposed of in various parts of the landfill, the nature and extent of contaminants, and exposures.