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, 1989. Concentrations of purgeable halocarbons and aromatic compounds detected in 336 wells (26 monitoring wells are located on base in Area A, B, C, D, and adjacent on-base areas and off-base in the Northwest and Southwest areas. There was no detected increase in the areal extent of contaminated groundwater, nor was there any increase in the depth that contaminated groundwater was detected. The Area D extraction system is effectively operating to change hydraulic gradients, so groundwater in Area D flows toward the extraction wells. Contaminant concentrations have decreased in Area D deep zone monitoring wells. Samples from three 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.