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� AMBRIA A demonstration that the drop in groundwater concentrations is not merely the result of groundwater elevations being approximately 10 feet lower than in the year 1998. Figure 7 shows the TPHg and MTBE concentrations, and groundwater elevation over time for well MW-1 Non-detect results are plotted at one-half the detection limit No benzene has been detected in well MW-1 since 1999, and concentrations have not exceeded 16 ppb since monitoring began, so benzene is not plotted As shown on Figure 7,TPHg concentrations decreased to at or below the detection linut in 2000, prior to the lowest groundwater elevations at the site MTBE concentrations also show a decreasing trend during this time Slight concentration increases of TPHg and MTBE are evident on the graph prior to 2003, but do not consistently correlate to changes in groundwater elevation MTBE concentrations actually show a general increasing trend between 2001 and 2002, while groundwater elevations were generally decreasing during that time period Furthermore, since 2004, intermittent high groundwater elevations are not associated with elevated TPHg or MTBE levels Based on this, Cambria believes the decrease in groundwater concentrations at the site are not merely a result of lower groundwater elevations at the site CHECKLIST OF REQUIRED DATA FOR NO FURTHER ACTION REQUESTS The site appears to meet the RWQCB-CVR cnten a for a low-risk groundwater designation The following are responses to the checklist items contained in Appendix A of the Tri-Regianal Board Staff Recommendations for Preliminary Investigation and Evaluation of Underground Tank Sites,dated April 16,2004 A copy of the checklist is included in Appendix E 1. Distance to production wells for municipal; domestic, agriculture, industry and other uses within 2000 feet of the site; Distances to identified production wells within a 2,000-foot radius of the site are showed on Figure 1 There is one municipal well located approximately 1,500 feet south of the site, and J several domestic wells located north of the site N 0323 g