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Geological Technics me Page 4 <br /> Groundwater Momtonng Report <br /> Protect No 425 2 <br /> June 25,2003 <br /> The sampling technician wore disposable gloves while collecting all samples <br /> A chain of custody document, listing all samples collected and their intended analyses, <br /> accompanied the samples from field to the laboratory, thereby providing a means to track <br /> ' the movement and insure the integrity of the samples <br /> 1.3 Laboratory Analyses <br /> The groundwater samples collected on June 6, 2003, were delivered to Sherwood Labs <br /> (Department of Health Services Certification No 1400), of Hilmar, California, for analysis <br /> The samples were analyzed using the following methods <br /> • BTEX—EPA method 8020/8015(m) <br /> 0 TPH-Gasolinc —EPA method 8020/8015(m) <br /> ® MTBE—EPA method 8020/8015(m) <br /> ' The detection limits for the above analyses are listed in Table 4 of Appendix A and the <br /> laboratory data are presented in Appendix B <br /> MAs required under A132886, the laboratory data were submitted electronically to GeoTracker <br /> on June 19, 2003 - confirmation number 5042073965 <br /> 2.0 FINDINGS AND DISCUSSION <br /> The laboratory analytical data generated during the June 6, 2003 groundwater-monitoring <br /> ' event indicate that gasoline constituents TPH-G & BTEX have been detected in monitoring <br /> wells MWA, MW-2, MW-4 and MW-5 <br /> ' The results of the June 2003 event are comparable with the results from previous <br /> monitoring events The following observations are made <br /> • The horizontal groundwater gradient, calculated from the water table wells, is currently <br /> ' towards the north-northeast <br /> • The gradient calculated from the intermediate wells is to the east-northeast <br /> ' • Vertical groundwater gradients were positive or upward in the shallow/intermediate and <br /> intermediate/deep well pairs <br /> • TPH-G concentrations in MW-1 continue to fluctuate within levels usually observed for <br /> ' the site The concentration of TPH-G in MW-1 measured during the June 2003 event <br /> were the lowest recorded at the site in three years See Figure 6 for a graph of Benzene <br /> and TPH-G versus time (MW-1) and Figure 8 for the distribution of TPH-G <br />