Dry Cleaners, Site Investigations/Remediation

Investigating and remediating releases of solvents from dry cleaning facilities is an area of special expertise and interest. Lord Associates has investigated a number of facilities where dry cleaning solvents (typically perchloroethylene or PCE), has been released to the environment. Given site conditions and the mass of the release, PCE has the potential to create a large scale groundwater problem.

We have been successful in predicting the fate and transport of large scale "plumes" of groundwater contaminated with PCE. Using analytical and numerical models toward this end lends a greater level of surety to the decisions regarding long term strategies or where to focus remedial efforts. Some of our experience is detailed below:

For a dry cleaning establishment on Cape Cod, Lord Associates investigated a long term historical release of PCE to a very permeable aquifer.

Remediation was initiated at the source to reduce the mass under the dry cleaning establishment. Lord Associates completed an Immediate Response Action Plan to initiate the active cleanup of soil and groundwater at the property via soil vapor extraction (SVE). Since the depth to groundwater is approximately 50 feet, it was believed that the majority of contaminates were residually adsorbed above the water table. The SVE system operated for a period of approximately 6 months, over which time approximately 1500 pounds of solvent were removed from the subsurface and recovered by steam regenerative carbon adsorption.

Calculation of aquifer characteristics predicted that the plume was likely to exist under the entire downtown area and have reached the shoreline of a nearby embayment. Based on the calculated model, sampling locations could be designated. Sampling of groundwater and seepage into the bay later confirmed the results of the model.

The results of a comprehensive investigation identified a complete migration pathway from the source area to a sensitive estuary located approximately 2,000 feet northeast of the subject property. Samples of groundwater seeps located within the lower inter-tidal region identified concentrations of 580 micrograms per liter (ug/L) of PCE. An exposure scenario developed to model the potential exposure of children to the affected groundwater determined that the risk of harm was not significant. Moreover, an ecological screening assessment concurred that the exposures to the environment were similarly not significant. Based on these conclusions, a satisfactory Response Action Outcome was achieved.

Lord Associates is currently investigating a dry cleaning facility located in a sensitive groundwater use area of south-central Massachusetts. An initial site investigation has indicated the presence of PCE-impacted groundwater at levels exceeding DEP RCGW-1 criteria within groundwater in the overburdened aquifer. In addition, although discharge of impacted water was terminated over five years ago, PCE-impacted discharge water was discovered within an on-site oil/water separator located in the parking lot of the facility.

Lord Associates, Inc. has designed a subsurface investigation program and soil vapor extraction Pilot Test to be conducted simultaneously at the site in order to complete all requirements for a DEP Phase I Initial Site Investigation and Release Abatement Measure Plan.