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1 - E11C``'R Mr James L Barton October 29, 2004 Page 8 8015 Modified, VOCs by EPA Method 8260B, CAM 17 Metals by EPA Methods 200 7, 200 8 ' and 245 1, and polynuclear aromatic compounds by EPA Method 8310 Except for motor oil and CAM 17 metals (arsenic, barium and zinc) detected at 5 5 lag/L, 21 pg/L, 350pg/L, and 190 lag/L, respectively, analytes were not detected at or above laboratory reporting limits Groundwater sample analytical results are summarized in Table 13 and copies of the laboratory analytical reports are included in Attachment D ESameling Schedule ' The fourth quarter 2004 sampling event occurred between October 18, 2004 and October 22, 2004 An Updated Site Conceptual Model, Monitonng and Remediation Status Report for Fourth Quarter 2004 will be submitted to the appropriate parties during January 2005 ' Groundwater samples were collected from wells MW-9R, and MW-28 through MW-30 during the fourth quarter sampling event Additionally, wells MW-9R, and MW-28 through MW-30 were added to the monitoring and sampling program ' Observations Groundwater analytical results for monitoring wells MW-1 through MW-9 indicate that the AS/SVE system appears to be effective at decreasing concentrations of dissolved TPHg and benzene in Unit Band Unit D beneath the site Monitoring wells MW-13, MW-25D and MW-27, screened in Unit B showed increases in benzene concentrations, whereas wells MW-15, and ' MW-18D screened in Unit B and MW-24D screened in Unit D showed increases in TPHg concentrations ' Concentrations of TPHg and benzene reported in soil vapor samples collected on August 30, 2004 showed an overall increase in TPHg and an overall decrease in benzene The highest reported concentrations of TPHg and benzene in soil vapor were detected in well MW-19S at 5,700 pg/L and 12pg/L, respectively Additionally, well MW-19S was the only well ' that had detectable concentrations MtBE in soil vapor above the laboratory reporting limit The groundwater gradients appear similar to previous quarters Seasonal groundwater ' elevation fluctuations of about 6 feet are evident in the historical groundwater elevation data MtBE was not detected at or above the laboratory reporting lima in any of the monitoring wells ' during the third quarter 2004 groundwater monitoring and sampling event w Consistent with the CAO, and in response to the RWQCB letter dated June 18, 2004, ENSR installed three new monitoring wells (MW-28, MW-29 and MW-30) during the third quarter 2004 These wells were requested due to an increase trend in benzene concentrations in three outlying wells (MW-7, MW-9, and MW-27) Results from the installation were submitted in ENSR's Monitoring Well Installation Report and Summary of Efforts to Cease Plume Movement on July 30, 2004 TPHg and benzene were not detected in groundwater samples from wells MW-28 through MW-30 at or above laboratory reporting limits I\DcsacramentolprojectslPro)ects10694OM98-2937inaRReports\Quartedy Mondonng ReportsW98 3rd Qtr 04-QMR doc Celebr?ta�q 3h Yea,r c,�Eacolreorp + Ewirwimenta Service,