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rsummarized in Table 2 and cumulatively summarized with previous analytical data in Table 3 Copies of the laboratory analytical reports are included as Appendix A Field observation forms, which include data on monitoring well purging and sampling, are included as Appendix B Figures 2 and 3 represent the distribution of TPH-g and benzene, respectively, in the groundwater as indicated by the 28 January 1992 groundwater analytical results Analytical results of groundwater sampling on 28 January1992 show that TPH-g concentrations have decreased on average by 25-30 percent in the wells located near and downgradient of the ' former tank field In contrast, the concentrations of TPH-g in samples from three wells located along Pershing Avenue have increased between 6 and 50 percent relative to analytical results of samples collected last quarter TPH-g was found at a concentration of 220,000 pg/L in the sample from well V4 and at a concentration of 150,000 pg/L in the samples from both V1 and V2 The levels of TPH-g measured in samples from wells PI and P2 were 2,000 and 2,900 pg/L, respectively Well RW3 was not sampled because of the presence of LPH The distribution of benzene dissolved in the groundwater closely resembles that of TPH-g Concentrations of hydrocarbons greater than method detection limits were reported for the first time to the sample from well MW12 Toluene was detected at a concentration of 0 6 pg/L, and xylenes were found at a concentration of 0 7 pg/L It is possible that these compounds were introduced during sampling, as the 28 January equipment blank contained toluene and xylenes at concentrations of 0 7 and 0 8 pg/L, respectively 6. WATER LEVEL RECORDS AND GRADIENT DETERMINATION ' groundwater ound Depths water were measured p T ed on 28 January 1992 Table 1 shows groundwater elevations and product thicknesses since January 1991 Figure 4 shows groundwater elevation tsocontours for 28 January 1992 Groundwater surface elevations increased by about 17 feet to the period between the gaugings of 15 October 1991 and 28 January 1992, reversing the trend of a declining water table, which had been observed from April to October 1991 The direction of groundwater flow remains roughly toward the east-northeast, which is consistent with previous measurements, at a hydraulic gradient of 0 01 WP51n3942(l)/QTRIJAN92JrX 5 3