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USA 65 QTR RPT JUL' 94 <br /> plotted from these depth-to-water measurements, ground water flow <br /> directions at the site were then inferred from the contour <br /> gradients This information is presented in Figure 4C <br /> Each well was purged before collecting water samples Purging <br /> was completed only after water temperature, pH, and conductivity <br /> had stabilized Purged water was contained in a labeled, secured <br /> 55 gallon drum on site <br /> The wells were allowed to recover after purging A water sample <br /> was then collected with a fresh bailer Each sample was divided <br /> among three 40-m1 VOA vials The vials are supplied pre-cleaned <br /> to exact EPA protocols and contain the appropriate preservative <br /> The sample vials were labeled as to station, well, time, and <br /> sampler, and documented on the chain-of-custody sheet, they were <br /> then placed into an ice chest, accompanied with a travel blank <br /> and cooled to 40C with ice The samples were delivered to a <br /> California State Certified Laboratory and signed over to the lab <br /> using standard chain-of-custody procedures Field notes <br /> describing the collection of water samples are included in <br /> Appendix A <br /> Chemical Analysis Results <br /> The water samples were analyzed at Anlab Analytical Laboratory <br /> . (DHS #1468 ) for Total Fuel Hydrocarbons (gasoline) with BTEX <br /> distinction, utilizing EPA Methods 5030 and 602 , respectively <br /> The analytical results from the water samples (MW3 , MW4 , and MW6) <br /> were all Below Reportable Limits (3RL) MW8 indicated a level of <br /> TFH of 200 ppm and Benzene <10000 ppb (detection limit increased <br /> due to dilution) <br /> The current localized impact of TFH-gasoline and benzene on <br /> ground water is depicted in Figures 5C and 6C The analytical <br /> results and pertinent reference data are listed in Table 1 <br /> Anlab' s laboratory report is included as Appendix B <br /> DISCUSSION OF RESULTS <br /> The ground water data obtained during the current monitoring <br /> round show significant changes since the last quarterly <br /> monitoring report Ground water flow direction is to the south- <br /> southeast with an average gradient of 0 003 feet per linear foot <br /> from MW4 to MW7, however, a ground water ' low' exists at MW8 and <br /> and a ' high' at MW4 , this may be attributable to local <br /> stratagraphic changes of lithology at the wells at this depth <br /> of the unconfined aquifer <br /> . 4 <br /> 1 <br />