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Boyett Petroleum • 419 Main Street, Manteca, California Quarterly Groundwater Sampling Report ' September, 2000 Narrative On September 9, 2000, Geo-Analytical Laboratories, Inc., conducted field measurements, well pumping and groundwater sampling on four (4) groundwater monitoring wells ' located at this site (Figures 1 and 2). Groundwater elevations were taken from four (4) wells prior to pumping (Table 1 & ' Appendix B). Monitoring wells MW-1 through MW-4 were evacuated by means of a steam-cleaned, stainless steel bladder type pump. During the three (3) volume pump down of each well, samples were collected to measure field pH, electrical conductivity and ' temperature (Table 3 & Appendix B). Once stability was achieved, a minimum of three (3)well volumes were removed and samples were collected with a disposable bailer. The . samples were then labeled and placed in an ice chest cooled with Blue Ice®. The samples were then togged on a Chain of Custody(Appendix A) and transported to the State-certified laboratory, GeoAnalytical Laboratory Inc., in Modesto, California. The analysis requested for the four (4) water samples was EPA method 8021B for BTX&E (Benzene, Toluene, Xylene, and Ethyl-Benzene) and MTBE (Methyl Tertiary Butyl Ether) ' and EPA method GCFID (5030/Luft) for gasoline. The analytes and concentrations detected are listed in Table 2 of this report. Groundwater Gradient ' The water level measurements from three (3) monitoring wells (MW-i, MW-2, MW-3) were used to construct a groundwater gradient map (Figure 3). This quarter, the groundwater gradient trend is South 10° East with a downward slope of 0.004 ft/ft. Since the sampling event in March 2000, the groundwater has fallen an average of 1.9 feet. FEstorical groundwater gradient maps are provided for reference in Appendix C. r . r