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� Ceofagtcaf?ethmes Inc Page 4 <br /> Groundwater Monitoring Report <br />' Project No 425 2 <br /> February 9, 1999 <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 /> their movement and insure their integrity <br /> 1.3 ]Laboratory Analyses <br /> The groundwater samples collected on November 13, 1998 were delivered to BSK Labs <br /> (Department of Health Services Certification No 1180), of Fresno, California, for analysis <br /> The samples were analyzed using the following methods <br /> a EPA method 602 - BTEX <br /> o EPA method 5030/8015(m) - TPH-Gasoline <br /> o EPA method 8260- Fuel oxygenate compounds (MTBE, D1PE, ETBE, TAME & TBA) <br /> The detection limits for the above analyses are listed in Table 4 of Appendix A and the lab <br /> data is presented in Appendix B <br /> 1 <br /> 20 IFANDINGS AND DSCUSSEON <br />'• The laboratory analytical data from this monitoring event shows that gasoline range <br /> petroleum hydrocarbons have been detected in the following monitoring wells MW-1, MW- <br /> 2, MW-4, MW-5 and MW-202 Figure 3 is a map with the groundwatet TPH-G <br /> concentrations plotted <br />' The results from the latest round of sampling are comparable with the results from the past <br /> monitoring events The following observations are made <br /> o Concentrations in MW-1 showed an increase from the last event See Figure 4 for graph <br />' of Benzene and TPH-G versus time in MW-1 <br /> o Concentrations in MW-2 showed a significant decrease from the past monitoring event <br /> Concentrations are within values observed in this well previously See Figure 5 for <br /> graph of Benzene and TPH-G versus time in MW-2 <br /> o Concentrations in MW-4 showed a decrease in BTEX and TPH-G from past monitoring <br />' events This event marks the lowest values in MW-4 observed to date <br /> o MW-5 showed a decrease in BTEX and TPH-G from past monitoring events This event <br /> marks the lowest values in MW-5 observed to date <br />' o MW-102 was non-detect for all constituents for the second event in a row <br /> o MW-202 showed decreases in BTEX and TPH-G, TPH-G is now non-detect <br /> o None of the fuel oxygenates were detected in any of the wells <br /> o The three domestic wells associated with the site were all non-detect for BTEX, TPH-G <br /> and the fuel oxygenate compounds <br />