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Geologleaf T"Aaks kc. Page 5 Groundwater Monitoring Report ' Project No.425.2 March 21,2005 ' Excelchem Labs included the results for 1,2 Dichloroethane in the results for 151 Quarter 05 sample analysis. ' The lab results for the above analysis are summarized in Table 8 of Appendix A, and the laboratory data are presented in Appendix B. ' As required under AB2886, the laboratory data, geo well data were submitted electronically to GeoTracker on March 21, 2005 -confirmation numbers are 3511268615 and 9197239518. ' The lab data has also been re-submitted on GeoTracker on February 23, 2005 for 4'h Quarter Monitoring 2004 —confirmation number is 3844143629. 1 2.0 RESULTS OF INVESTIGATIONS Table 8 of Appendix A is a summary of analytical groundwater data. Groundwater analytical results and field observations are discussed below. ' a MW-2X, MW-3, MW-6, MW-8, MW-101, MW-102, MW-201, and all sampled domestic wells were non-detect above laboratory reporting limits for all analyzed constituents. a Small concentrations of 1,2 Dichloroethane has been found in MW-4 (3.6 ttg/L), MW-5 (9.6 µgIL), MW-7 (1.6 µgfL), and MW-106 (3.2 µgfL). ' a MW-4 and MW-5 showed low to moderate levels 0 to 2 digits) of BTEX constituents. a MW-1, MW-4, and MW-5 showed moderate to high levels (2 to 4 digits) of TPH-G ' constituents. a MW-l showed elevated concentrations of Benzene, Ethyl Benzene, Xylenes and TPH-gasoline as compared to historical analytical data. a MW-2 continues to show high concentrations of TPH-G, and BTEX constituents during this monitoring event and also in the historical data. ' . The monitoring wells: MW-2X (well screen 32.5-35 ft bgs), and MW-102 (well screen 45.0-47.5 ft bgs) do not show any contamination. This indicates that contamination did not move to the deeper zones of water aquifer near MW-2 (the tplace of highest contamination). ' 3.0 FINDINGS AND DISCUSSION The laboratory analytical data generated during the January 21, 2005 groundwater-monitoring ' event indicates that MTBE and/or TPH-G and BTEX constituents have been detected in monitoring wells: MW-1, MW-2, MW-4, MW-5, and MW-106.