The geology of the site area is characterized by low-permeability fractured glacial till overburden overlying fractured bedrock. The overburden and bedrock aquifers have been classified for drinking water; however, the aquifers are not expected to yield sustainable, significant quantities of water for use as a public supply of drinking water.
Targeted Environmental Media:
 Dense Non-aqueous Phase Liquids (DNAPLs) - Fractured Bedrock
Based on monitoring data available as early as the 1980s, the plume appears to be in a steady state and is not expected to migrate further.
Major Contaminants and Maximum Concentrations:
- Trichloroethene (2,500 µg/L)
- Dioxane (34 µg/L)
- Tetrachloroethene (210 µg/L)
- 1,2-Dichloroethene (640 µg/L)
- Methylene chloride (51 µg/L)
- Vinyl chloride (18 µg/L)
- Lead (0 µg/L)
- Chromium (0 µg/L)
- Arsenic (25 µg/L)
No technologies selected.
- Soil Vapor Extraction
- In Unconsolidated Overburden
Comments:
EPA is addressing contamination in soil and soil vapor using soil vapor extraction (SVE), excavation, and off-site disposal. Volatile organic compounds (VOCs) will be treated using SVE, and the remaining contaminated soil will be excavated.
Contamination in the shallow overburden aquifer will be addressed using soil excavation and off-site disposal. The areas of the property that are serving as an ongoing source of groundwater contamination will be excavated.
Site-wide groundwater contamination is being addressed by providing a permanent alternative water supply. The residences affected by the groundwater contamination are served by point-of-use carbon filters. These residences and a buffer zone of residences will be connected to the Middletown Water Distribution System as part of the remedy.
EPA is addressing the source zone through a no action remedy and the dissolved plume through a limited remedy with a contingency to implement hydraulic containment if it is determined that the overall plume or source zone spreads or migrates beyond its current boundary.
According to the EPA, it is technically impracticable to clean up the groundwater to drinking water standards in a reasonable period. It is expected that the plume would not be restored within several hundred years because of the persistence of contamination observed since the 1980s and the extensive fractured bedrock in the area. No technologies are available that are known to be effective in restoring dense nonaqueous phase liquid (DNAPL) zones in complex heterogeneous geologic environments to drinking water quality in a reasonable time. Therefore, EPA is requesting a Technical Impracticability Waiver of Applicable or Relevant and Appropriate Requirements (ARAR) associated with groundwater cleanup.
The cleanup plan described in this profile is currently proposed.
Reference:
http:www.clu-in.orgproductstins : Proposed Plan: Durham Meadows Superfund Site, Durham, CT U.S. EPA Region 1, 30 pp, July 2005. Full text available at http:www.epa.govnesuperfundsitesdurham67326.pdf
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