Book Description
This Data Summary presents the results of groundwater sampling activities conducted on and in the vicinity of McClellan Air Force Base from the sampling period of January through March 1990. Concentrations of purgeable halocarbons and aromatic compounds detected in 49 wells (39 monitoring wells and 10 extraction wells) exceeded state and/or federal drinking water standards. These wells are located on-base in Areas A, B, C, D and adjacent on-base areas and off-base in the Northwest and Southwest areas. The Area D extraction system is effectively operating to change hydraulic gradients, so groundwater in Area D flows toward the extraction wells. Samples from two middle zone monitoring wells located in Area D also show decreases in contaminant concentration during this sampling period. Decreasing contaminant concentrations have stabilized in shallow zone monitoring wells located off-base, west of Area D.