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r <br /> f <br /> 28 March 1997 <br /> AGE-NC Project No 95-0144 <br /> 1 Page 2 of 3 <br /> ' McCampbell Analytical, Inc (MAI) in Pacheco, California, and were analyzed for total petroleum <br /> hydrocarbons quantified as gasoline (TPH-g), diesel (TPH-d), and motor oil (TPH-mo) and for <br /> volatile aromatic compounds (benzene, toluene, ethylbenzene and xylenes, BTE&X) with methyl T <br /> 1 tertiary-butyl ether (MTBE) in accordance with EPA methods 5030 and 602, respectively <br /> 3 0. FINDINGS <br /> 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT <br /> ' The relative elevation of round water in each well was calculated b subtiactin the depth to water <br /> g Y g p <br /> from the surveyed casing elevation(Table 1) Ground water elevation increased an ai,erage of 5 07 <br /> ' feet between November 1996 and February 1997 The approximate gradient for the February 1997 <br /> monitoring,was calculated to be 0 0074 ft/ft with a northerly flow direction Ground water elevation <br /> ' contours derived from data collected on 04 February 1997 are depicted in Figure 3 <br /> I <br /> 32 ANALYTICAL RESULTS OF WATER SAMPLES <br /> During the February 1997 monitoring event, TPH-g was detected in wells MW-1 and MW-5 at <br /> concentrations of 850 parts per billion (ppb, reported as micrograms per liter) and 170 ppb, <br /> respectively, TPH-d was detected in wells MW-1, MW-2, MW-5, MW-11 and MW-12 at <br /> concentrations as high as 300 ppb TPH-mo was not detected in samples collected duiing the <br /> ' February 1997 monitoring event BTE&X were detected in MW-1 at concentrations of 9 7 ppb, 25 <br /> ppb, 7 1 ppb and 230 ppb, respectively Xylenes were detected in MW-5 at a concentration of 22 <br /> ppb Petroleum hydrocarbons were not detected in wells MW-4, MW-8, MW-13 or MW-18 r <br /> Analytical results s ul <br /> is of ground,, ater samples are summarized on Tables 2 and 3 The laboratory report <br /> ' (MAI Laboratory I D Nos 73473 - 73481) and chain-of-custody forms are included in Appendix <br /> I g <br /> ' 4.0. CONCLUSIONS AND RECOMMENDATIONS <br /> 1 41 CONCLUSIONS <br /> Based upon data collected from the site, the following conclusions are presented <br /> ' Ground water elevation showed a significant increase during the firstq uarter of 1997 This <br /> is consistent with findings at other sites in the Stockton area <br /> 1 , <br />