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28 concentration of TPHg declined between the 60 ft bgs sample and the 70 ft bgs sample by a factor of 4 7 The concentration of benzene declined between the 60 ft bgs sample and the 70 ft bgs sample by a factor of 17 5 Despite the fact that 80 and 90 foot sampling zone yielded no water, a monitoring well (NP-1) screened from 85 to 90 ft bgs was installed and completed at the direction of SJCPHS h The well yielded water and a subsequent sample taken during the quarterly groundwater ' monitoring effort one month later had concentrations of TPHg and benzene of 6,000 and 210 ug/L, respectively During well development and purging, NP-1 could not be bailed or ' pumped dry These facts indicate that water is likely moving in somewhat permeable "stringers" that are interlayered with much less permeable zones at this depth This also indicates that the flow is highly anisotropic and much greater in the horizontal direction than in the vertical direction Five feet away from NP-1, another well (MW-10)was installed and completed with a screened interval set between 50 and 60 ft bgs Concentrations of TPHg and benzene in MW- 10 were 160,000 and 14,000 ug/L, respectively Agreement between the concentrations of TPHg and benzene from the Sinulprobe grab sample taken from the 50 and 60 ft bgs depths and the quarterly monitoring sample taken ' from MW-10 screened between 50 and 60 ft bgs was good ' The concentrations of TPHg and benzene in the quarterly monitoring sample taken at NP-1 were a less than those i1 the Snnulprobe sample taken from the 70 ft bgs above it by factors of 6 0 and 5 7 respectively Further, concentrations of TPHg and benzene in NP-1 are less than those detected in the monitoring well MW-10, approximately 5 horizontal feet away ' and with the highest concentrations detected in the quarterly monitoring event, by factors of 26 7 and 66 7, respectively 1