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i <br /> I� <br /> Free Product <br /> Measurable free product was not observed in any of the wells. Trace free product as slight <br /> sheen was observed in Monitoring Well MW-9 during sampling <br /> GROUND WATER SAMPLING <br /> Ground water samples collected from Monitoring Wells MW-1 through MW-15 June 19, <br /> 1992, were transported to a California-certified laboratory for analysis. <br /> Laboratory results of ground water sampling June 19, 1992, are summarized in Table 1. The <br /> official laboratory reports and chain of custody record are presented in Appendix C. <br /> FINDINGS <br /> I� <br /> • Ground water elevations have decreased 1.15 feet on average since the previous <br /> quarterly event May 31, 1992. <br /> • The general ground water gradient is to the northeast with a magnitude 0 003 <br /> ft/ft, consistent with previous monitoring events. <br /> • Measurable free product was not observed in any of the wells during this event. <br /> • Trace free product was observed as a slight sheen in MW-9. <br /> • Discoloration of standing water in monitoring well boxes was observed in MW-8 <br /> and MW-9, and was documented onsite with photographs. The discoloration is <br /> probably a result of fermented dairy products washed into the box from surface <br /> runoff. <br /> • Based on analysis of ground water samples collected June 19, 1992, maximum <br /> concentrations of TPH-G and benzene were detected in Monitoring Wells MW-9 <br /> (66,000 and 7600 ppb), MW-10 (37,000 and 8300 ppb), MW-8 (5000 and 970 <br /> ppb), and MW-1 (1400 and 300 ppb). Monitoring Wells MW-8 and MW-9 are <br /> in the vicinity of the former underground storage tanks. <br /> • Benzene and TPH-G concentrations have increased in ground water samples <br /> collected from MW-8 and MW-9 since the previous quarterly sampling event,but <br /> have decreased in MW-1 and MW-10. TPH-G and BTEX were not detected at <br /> or above reported detection limits in other monitoring wells. <br /> 2 <br />