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: January 1, 2011

Point of Contact:
Jim DiLorenzo
USEPA 5 Post Office Square, Suite 100
Mail Code OSRR07-4
Boston MA 02109-1367 
Tel: 617-918-1247 
Email: dilorenzo.jim@

Nyanza Chemical Waste Dump
Ashland, MA


The Site directly overlies glacial sediments, which in turn overlie
granitic bedrock. The bedrock surface is undulating and slopes downward
from Megunko Hill toward the Sudbury River with a small trough paralleling
the Sudbury River in a general east-west orientation between Pleasant
Street and the railroad tracks. Depth to bedrock generally increases from
the hillside (5 to 10 feet) toward the lowlands and the Sudbury River (20
to 50 feet). The greatest depths to bedrock (50 to 100 feet) occur in what
is interpreted as a bedrock depression, or trough, parallel to the southern
shore of the Sudbury River and then trending south in the general area near
the intersection of Park Road and Summer Street.

Groundwater probably discharges to the Sudbury River above MW-304 and below
the Myrtle Street dam; the river reach in between is likely an area of
induced infiltration from the river. The probability of groundwater flow
beneath the river is very low.

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


The plume is about 1,350 feet at its widest and 2,700 feet long. The is some discharge into the Sudbury River. Contaminant concentrations are higher in the bedrock than they are in the overburden.

Major Contaminants and Maximum Concentrations:
  • - Trichloroethene (5,100 µg/L)
  • - 1,2-Dichloroethene (1,600 µg/L)
  • - Aniline (24,000 µg/L)
  • - 1,2-Dichlorobenzene (6,600 µg/L)
  • - Nitrobenzene (5,300 µg/L)
  • - 1,2,4-Trichlorobenzene (5,000 µg/L)
  • - Chlorobenzene (3,900 µg/L)

Site Characterization Technologies:

  • - Coring
  • - Other (non-specified geophysical)

Remedial Technologies:

  • - Pump and Treat
The original pump and treat extraction system pumps were destroyed by the DNAPL chemical mixture groundwater emulsion that pumping produced and the system was shut down.
Remediation Goals:

The cleanup goals were MCLs.


Groundwater pumping has not occurred since 1994. A pumping system to removal DNAPL mass was expected to become active in 2010.

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