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Study
3.
Identify distinct source
of DNAPL-like chlorinated solvent concentrations some 800 feet downgradient of
site.
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Objective.
To identify distinct source of DNAPL-like chlorinated solvent concentrations some 800 feet downgradient of
site.
Site Information
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Contaminated groundwater from site (with known DNAPL
source) was migrating offsite
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PCE at
DNAPL-like concentrations was identified in groundwater some 800 feet
downgradient of the site and attributed to our client's site. |
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Click on the graphic for a larger view. |
Sampling Strategy
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Designed CPT/Hydropunch
sampling strategy.
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Data from
the CPTs was used to develop 3D model of the subsurface lithology.
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Depth-discrete preferential sand channels were identified in 3D.
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Depth-discrete grab groundwater results were plotted in 3D. |
Results
3D Modeling
showed that;
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A new DNAPL source had been identified
with 100,000 ppb PCE reported in CPT-5 at approximately 31 ft bgs.
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This elevated PCE was present in a thin
sand lens outside the preferential pathway for flow of groundwater originating
from our client's site.
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Concentrations of PCE upgradient were
orders of magnitude lower than those at the newly-identified DNAPLlike source.
For more
information about Risk-Based Decisions, Inc. call (916) 923-0570,
send
email or complete
our
online information request form.
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