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1 <br /> Bo ett Petroleum <br /> j 419 Main Street, Manteca, California <br /> Quarterly Groundwater Sampling Report <br />' March, 2000 <br />' Narrative <br />' On March 27, 2000, GeoAnalytical Laboratories, Inc., conducted field measurements, well <br /> pumping and groundwater sampling on four (4) groundwater monitoring wells located at <br /> this site (Figures I and 2). <br /> Groundwater elevations were taken from four (4) wells prior to pumping (Table 1 & <br />' Appendix B). Monitoring wells MW-1 through MW-4 were evacuated by means of a <br /> steam-cleaned, stainless steel }Madder type pump. During the three (3) volume pump <br /> down of each well, samples were collected to measure field pH, electrical conductivity and <br /> temperature (Table 3 & Appendix B). Once stability was achieved, a minimum of three <br /> (3) well volumes were removed and samples were collected with a disposable bailer. The <br /> samples were then labeled and placed in an ice chest cooled with Blue Ice®. <br /> The samples were then logged on a Chain of Custody (Appendix A) and transported to the <br /> State-certified laboratory, GeoAnalytical Laboratory Inc., in Modesto, California. The <br /> analysis requested for the four (4) water samples was EPA method 602 for BTX&E <br /> (Benzene, 'Toluene, Xylene, and Ethyl-Benzene) and MTBE (Methyl Tertiary Butyl Ether) <br /> and EPA method GCF1D (5030/Luft) for gasoline. EPA method 8260 was used to test <br />' for Ethanol, tertiary-Butanol, Di-isopropyl Ether (DIPE), Ethyl tertiary-Butyl Ether <br /> (ETBE), tertiary-Amyl Methyl Ether (TAME) and to confirm MTBE contamination. The <br /> analytes and concentrations detected are listed in Table 2 of this report. <br />' Groundwater Gradient <br /> The water level measurements from three (3) monitoring wells (MW-1, MW-2, MW-3) <br />' were used to construct a groundwater gradient map (Figure 3). This quarter, the <br /> groundwater gradient trend is North 30° East with a downward slope of 0.016 ft/ft. Since <br /> the sampling event on December 10, 1999, the groundwater has risen an average of 1.7 <br />' feet. Historical groundwater gradient maps are provided for reference in Appendix C. <br />