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• Chemical analysis <br /> The groundwater samples collected were analyzed for Total Petroleum <br /> Hydrocarbons as Gasoline (TPHG) and Benzene, Toluene, Ethylbenzene <br /> and Xylene (BTEX) . The groundwater samples were analyzed for TPHG <br /> by EPA Method 8015 modified with purge and trap preparation 5030 <br /> (GC/FID) with detection limits of 50ug/l. EPA Method 602 was <br /> utilized for BTEX with a detection limit of 0.5ug/1 as required by <br /> the SJCEHD. <br /> The results of the analysis of the groundwater samples in parts per <br /> billion (ppb) are shown in Table 3 . The laboratory data sheets <br /> with detection limits and COC documentation are contained in <br /> Appendix B. <br /> TABLE 3 <br /> Decenber 6, 1995 Groundwater sample Analysis Results in ppb. <br /> Sample ID TPHG B T E R <br /> MW-1 1,700 ND 2. 1 48 14 <br /> MW-2 2, 300 450 12 29 15 <br /> • MW-3 7 , 500 180 8. 6 420 24 <br /> ND = Not Detected <br /> The concentrations of TPHG and BTEX in the groundwater are high. <br /> Quarterly sampling should be continued for at least one more <br /> quarter, to determine the water quality and gradient status over a <br /> year period. <br /> SUMMARY, CONCLUSIONS AND RECOMMENDATIONS <br /> The groundwater samples from the three wells had actionable levels <br /> of TPHG and Benzene. <br /> The calculated gradient is to the southwest at approximately 0.001 <br /> ft/ft. <br /> The levels of TPHG and BTEX in groundwater are similar to the <br /> values reported in the first and second quarter environmental <br /> investigation at this site. Continued quarterly monitoring <br /> readings obtained over a longer period of time should indicate a <br /> consistent gradient or provide a reason for the gradient <br /> variability. <br /> . 6 <br />