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4.0 FINDINGS <br /> 4.1 Relative Groundwater Elevation and Gradient <br /> The relative elevation of groundwater;n each well was calculated by subtracting the depth <br /> ' to groundwater from the surveyed relative casing elevation (Table 1) Groundwater rose <br /> approximately three feet since the November 1993 monitoring event The gradient was <br /> calculated to be 0 0033 ft/ft directed N 47° E (Figure 3). This is consistent with data from <br /> the November monitoring and data from nearby wells (USA Gasoline, located southeast of <br /> the site) <br /> ' 4.2 Laboratory Evidence of Groundwater Contamination <br /> TPH as diesel was detected in water samples from MW-1, MW-2 and MW-3 at <br /> concentrations of 90 ppb, 100 ppb, and 110 ppb respectively No TPH as gasoline, benzene, <br /> ethylbenzene, toluene or xylenes were detected in the water samples The analytical results <br /> 1 of the samples are listed in Table 2 The laboratory report and chain-of-custody are included <br /> in Appendix B <br /> TABLE 2 <br /> ANALYTICAL RESULTS of WATER SAMPLES <br /> Pacific Gas <br /> AWL <br /> ' Sample TPH as TPH as Ethyl- <br /> ID Gasoline Diesel Benzene Toluene benzene Xylene <br /> ' MW-1/11-10-93 ND 260 ND 199 ND ND <br /> MW-1/5-27-94 ND 90 ND ND ND ND <br /> ' MW-2/11-10-93 ND 390 ND ND ND ND <br /> MW-2/5-27-94 ND 100 ND ND ND ND <br /> ' MW-3/11-10-93 53 140 ND 2 4 ND ND <br /> MW-3/5-27-94 ND 110 ND ND ND ND <br /> parts per bilhon <br /> ND = Not Aeteded <br /> 4.3 Historical Map Search <br /> In April 1994, an historical search of Sanborn Fire Insurance Maps was performed for the <br /> ' area around the Site The search was performed by ERIIS of Alexandria, Virginia Previous <br /> conversations with the Client and local residents revealed that UST's may have been located <br /> � ,,�S-�U. 6 <br />