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DETECTION OF A GROUND-WATER/SURFACE-WATER INTERFACE WITH DIRECT-PUSH EQUIPMENT
Citation:
Hurt, K. L., J T. Wilson*, AND D S. Burden*. DETECTION OF A GROUND-WATER/SURFACE-WATER INTERFACE WITH DIRECT-PUSH EQUIPMENT. Presented at American Geophysical Union 2000 Spring Meeting, Washington, DC, 5/30-6/3/2000.
Description:
A ground-water/surface-water interface (GSI) was documented at the Thermo Chem CERCLA Site in Muskegon, MI via direct-push (DP) sampling. At that time, contaminated ground water flowed from the upland area of the site into the Black Creek floodplain. DP rods equipped with a 1.5-ft long exposed-screen were driven into the bank of Black Creek approximately 1 ft from the waterline. Samples were taken on continuous 1.5 ft intervals from the water table, encountered 2.5 ft below ground surface (bgs), to 14.5 ft bgs and analyzed at the U.S. EPA's Robert S. Kerr Environmental Research Center for: tetrachloroethene (PCE), trichloroethene (TCE), cis-1,2-dichloroethylene (DCE), vinyl chloride (VC), benzene (B), toluene (T), ethyl benzene (E), m-, p-, and o-Xylene (XXX), sulfate, and chloride. Dissolved oxygen and Fe (II) were measured in the field. At depth, ground-water samples had the following characteristics: relatively low levels of PCE, TCE, sulfate and dissolved oxygen along with relatively high levels of DCE, VC, BTEXXX, Fe (II), and chloride. Ground-water samples taken nearer the bed of Black Creek had the following characteristics: relatively low levels of DCE, VC, BTEXXX, Fe (II), and chloride along with relatively high levels of sulfate and dissolved oxygen. PCE and TCE concentrations were similar at all intervals. A gradual transition was observed between the concentrations of all other analytes from deeper intervals to shallow intervals. These trends suggest that the geochemical influence of surface water on shallow zones encourages the degradation of contaminants susceptible to aerobic biodegradation processes. Conversely, these trends imply that the aerobic conditions encountered at shallow depths impeded or stopped degradation of those contaminants requiring anaerobic conditions for destruction.