U.S. EPA Contaminated Site Cleanup Information (CLU-IN)


U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Fractured Bedrock Project Profiles

Last Updated: September 30, 2003

Point of Contact:
Steve Johnson
Massachusetts DEP
1 Winter Street
Boston MA 02103 
Tel: 617-654-6561 
Email: Stephen.johnson@
state.ma.us

Sterling Supply Co.
North Reading, MA


Hydrogeology:

Overburden material at this site consists of sand and gravel outwash, and possible kame terrace deposits of late Pleistocene age. Holocene fluvial deposits associated with the nearby Ipswich River are also present. The bedrock surface dips to the southeast; depth to bedrock varies from approximately 12 feet to > 40 feet. Bedrock at the site varies from granodiorite subjected to low grade metamorphism to weakly foliated gneiss.

Targeted Environmental Media:
  • - Dense Non-aqueous Phase Liquids (DNAPLs)
  • - Fractured Bedrock

Contaminants:

Multiple small releases/ spills of chlorinated solvents (primarily PCE) at this former dry cleaning supply company have resulted in a plume of PCE approximately 400 feet wide by at least 600 feet long.

Major Contaminants and Maximum Concentrations:
  • - Tetrachloroethene (7,400 µg/L)

Site Characterization Technologies:

  • - Vertical Chemical Profiling
    • Packer Isolation
  • - Coring

Remedial Technologies:

  • - Pump and Treat
  • - Soil Vapor Extraction
    • With Air Stripping
Comments:
The ground water pump and treat system at this site, which consists of two recovery wells, and treatment with a low profile air stripper and activated carbon, has been in operation at this site since May, 1994. The system has recently been improved by the replacement of original overburden recovery wells (originally designed for mass removal in the overburden aquifer), by bedrock recovery wells drilled to about 45 feet.

A soil vapor extraction system was originally installed in 1994 to mitigate high levels of VOCs in the vadose zone. Because recovery concentrations have leveled off the system has been run intermittently.

Altough concentrations in monitoring wells have leveled off, concentrations in a municipal well 800 ft from the site have decreased significantly.

Remediation Goals:

None provided


Status:

In September, 2003, state officials are confident that the system is containing the plume. This is based on the levels in the monitoring wells and the municipal well. The SVE system will remain off for a few months to see if a rebound occurs.

Top of Page

For more information on Fractured Bedrock, please contact:

Ed Gilbert
Technology Assessment Branch

PH: (703) 603-8883 | Email: gilbert.edward@epa.gov