The site consists of a overburden layer of dark red to brown clayey silt up to 30 feet below ground surface (bgs) underlain by fractured limestone bedrock. Ground water was identified within the bedrock at approximately 40 feet bgs. Hydraulic conductivity has been reported to be between 4.3x10-4 centimeters per second (cm/sec) and 8.6x10-3 cm/sec.
Targeted Environmental Media:
 Fractured Bedrock
A lateral or vertical extent was not identified.
Major Contaminants and Maximum Concentrations:
- 1,2-Dichloroethene (0 µg/L)
- Vinyl chloride (0 µg/L)
- 1,4-Dichlorobenzene (0 µg/L)
- Trichloroethene (0 µg/L)
- Aroclor 1260 (0 µg/L)
- 4,4'-DDT (0 µg/L)
- a-BHC (0 µg/L)
No technologies selected.
- Chemical Oxidation (In Situ)
Comments:
Four injection events took place (events I through IV). Twenty-six wells in Area # 2 were used for injection during Events I and II. Nine wells in Area # 1 and 17 wells in Area # 2 were used during Events III and IV. Inflatable straddle packers were used within each injection well to isolate the bedrock fractures. Each well was divided into three zones: the lower treatment zone (ranged from 70 to 100 feet bgs), the middle treatment zone (ranged from 40 to 70 feet bgs), and an upper treatment zone (bedrock interface 40 feet bgs). Injections in each well occurred in the lower, middle, and upper treatment zones, in that order, depending on the well and where bedrock was reached. Twenty upgradient, side-gradient, and downgradient monitoring wells were sampled before and after each injection event.
The objective for the study was to evaluate in situ chemical oxidation using Fentons reagent on the removal of contaminants of concern within the fractured bedrock.
Results indicated that 15 of the 20 wells that were sampled during the final sampling event showed chlorobenzene at concentrations below remedial goals; 1,2-DCE and VC were below remedial goals in 12 of the wells; TCE was below remedial goals in eight wells; Aroclor 1260 was below remedial goals in 13 wells; 1,4-DCB was below remedial goals in 19 wells; 4,4-DDT was below remedial goals in 18 wells, and alpha-BHC was below remedial goals in 19 wells. Individual cleanup goals were not identified in the reference cited.
References: Prasad Kakarla, Thomas Andrews, and Michael Temple. Modified Fentons Remediation of a Fractured Bedrock Aquifer Using a Network of Multi-Zone Packered Wells. The Fifth International Conference on Remediation of Chlorinated and Recalcitrant Compounds. May 22-25, 2006. Monterey, California.
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