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: December 31, 2010

Point of Contact:
Claire Willscher
USEPA 5 Post Office Square, Suite 100
Mail Code OSRR07-1
Boston MA 02109-3912 
Tel: 617-918-1794 
Email: willscher.claire@

Central Landfill
Johnston, RI


The area in the vicinity of Central Landfill is typically underlain by glacial till, which in turn is
underlain by fractured granitic bedrock.

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


A decision was made by EPA not to treat the plume but to concentrate on an 1/2 acre area where liquid hazardous wastes were discharged directly to the bedrock.

Major Contaminants and Maximum Concentrations:
  • - Chlorobenzene (50,000 µg/L)
  • - 1,2-Dichlorobenzene (42,000 µg/L)
  • - Benzene (2,000 µg/L)
  • - Copper (100 µg/L)
  • - Lead (210 µg/L)
  • - 1,4-Dichlorobenzene (NA)
  • - Beryllium (NA)
  • - Tetrachloroethene (NA)
  • - Trichloroethene (NA)
  • - Vinyl chloride (NA)

Site Characterization Technologies:

  • - Vertical Chemical Profiling
    • Packer Isolation
    • Multi-sampling port
  • - Pumping Tests

Remedial Technologies:

  • - Pump and Treat
The one extraction well pump and treat system became operational in September 2006.
Remediation Goals:

MCLs where appropriate


Pumping continues. There have been statistically significant decreases in many of the contaminant of concern concentrations.

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