|
Introduction:
Argonne
National Laboratory (ANL) has an agreement
with the Commodity Credit Corporation of the
U.S. Department of Agriculture (CCC/USDA) to
perform site investigations to characterize
soil and groundwater contamination
associated with several former grain storage
facilities in Nebraska and Kansas. As part
of these site investigations, ANL needs the
services of environmental geophysicists to
provide expert advice on the use of
geophysical techniques to describe and
delineate subsurface geologic and
hydrogeologic conditions. Further, ANL wants
to display contaminant plumes at these sites
in three-dimensions using software designed
for 3D visualization.
The
Earth Sciences and Resources Institute (ESRI-USC)
at the University of South Carolina is
providing geophysical expertise and
oversight to Argonne National Laboratory's (ANL)
QuickSiteSM
investigations of subsurface DNAPL
contamination at former USDA Commodity
Credit Corporation grain storage sites in
the Midwest. At these sites materials used
to fumigate grain decades ago are the cause
of DNAPL contamination. The DNAPL, commonly
carbon tetrachloride, migrates through the
overlying glacial sediments and accumulates
on clay layers and atop the bedrock surface
at depths to 100 feet. Insofar as many CCC
sites were located within or near town
limits, the potential for contamination of
public drinking supplies is high. Because
the geological characteristics of the
glacial overburden are laterally and
vertically variable, geophysical methods are
needed to detect and map buried channels and
other heterogeneities that might influence
contaminant transport
|
