Volatile organic compounds in ground water west of LLNL
Using a methodology developed to evaluate the vertical extent of VOCs in multiple water-bearing zones in a single borehole, saturated soil samples were collected and analyzed for VOCs. Ground water from the 46 monitor wells and 14 existing offsite wells was analyzed for VOCs, metals, major inorganics, and other constituents. Geologic sections, prepared for this study, indicate that the western portion of LLNL and the vicinity of Arroyo Seco to the west are underlain by gently dipping, complexly interfingering, alluvial sediments of highly variable permeability. These sediments were probably deposited by northwest-flowing, meandering and/or braided streams. Seven VOCs, tetrachloroethylene (PCE), trichlorethylene (TCE), 1,1-dichloroethylene (1,1-DEC), trans-1,2-dichloroethylene (trans-1,2-DEC), 1,1-dichloroethane (1,1-DCA), 1,2-dichloroethane (1,2-DCA), and carbon tetrachloride (CCl/sub 4/), were detected in ground water in the study area in concentrations exceeding action levels recommended by the California Department of Health Services. Of these, trans-1,2-DCE, 1,1-DCA, 1,2-DCA, and CCl/sub 4/ have been detected only sporadically and/or in fewer than 6 of the 60 regularly sampled wells. Geologic and chemical data from saturated soil and ground water samples indicate that VOCs have migrated westward and downward from the southwest part of LLNL in overlapping, northwest-dipping alluvial sediments. Buried meandering and/or braided stream channels may constitute preferred pathways for migration of ground water and VOCs. The VOC plume west of LLNL is presently about 3600 ft. long and 1700 ft. wide. Near the apparent source of the VOC plume in the southwest corner of LLNL, VOCs are not present below a depth of about 90 ft. Near the leading edge of the plume, VOCs are not present below a depth of about 200 ft.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5323615
- Report Number(s):
- UCRL-53740; ON: DE86014651
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GROUND WATER
MONITORING
ORGANIC COMPOUNDS
ECOLOGICAL CONCENTRATION
ENVIRONMENT
ENVIRONMENTAL TRANSPORT
EXPERIMENTAL DATA
LAWRENCE LIVERMORE LABORATORY
VOLATILE MATTER
DATA
HYDROGEN COMPOUNDS
INFORMATION
MASS TRANSFER
MATTER
NATIONAL ORGANIZATIONS
NUMERICAL DATA
OXYGEN COMPOUNDS
US AEC
US DOE
US ERDA
US ORGANIZATIONS
WATER
520200* - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)