ARCHIVED REPORTS_FIRST QUARTER 2011 STATUS SUMMARY REPORT

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Stantec First Quarter 2011 Status Summary Report Former Tosco Bulk Terminal No. 10013 April 29, 2011 submersible pumps and disposable bailers, and water quality parameters were measured repeatedly until the readings stabilized. The Field Data Sheets for the first quarter 2011 sampling event are presented in Appendix D. BC Laboratories, Inc. (BC) accredited by the California Environmental Laboratory Accreditation Program, performed the analyses for this MRP. Samples submitted to BC were tested for combinations of the following analytes: BTEX by EPA Method 8260B; TPH-d ,TPH-g by EPA Method 8015M; • Oxygenates including MTBE, di-isopropyl ether (DIPE), tert-amyl methyl ether (TAME), TBA, ethyl tert-butyl ether (ETBE), methanol, and ethanol by EPA Method 8260B- Modified. Maximum detection limits provided to the laboratory for the analytes are presented in Table 1. Groundwater Analytical Results The field groundwater quality parameters recorded for the wells that were gauged, purged and sampled during the current monitoring event are listed on the Field Data Sheets in Attachment D. The groundwater analytical results for the sampled monitoring wells are presented in Table 4. The analytical laboratory report and chain-of-custody documents are provided in Appendix D. Historical groundwater monitoring results are provided in Appendix B. "A" Zone MTBE and TBA concentration contour maps for the first quarter 2011 are illustrated on Figures 6 and 7. Historical groundwater elevations and chemical concentration trend charts for wells MW-1, MW-2, MW-8 and MW-14 are illustrated on Figures 8 through 11. The following is a summary of the groundwater analytical results for the first quarter 2011: • TPH-g was reported in only well MW-19C at 65 pg/L. However, according to the laboratory analytical note A91, the TPPH concentrations detected in wells MW-19C was due entirely to MtBE. TPH-d was detected in 8 of the 16 wells sampled at concentrations ranging from 74 pg/L (MW-18C)to 240 pg/L (MW-2). • MTBE was detected in 10 of the 15 wells sampled at concentrations ranging from 0.59 pg/L (MW-1) to 54 pg/L (MW-19C). MTBE concentrations were above the secondary action level of 5 pg/L only in the groundwater samples collected from wells MW-16, MW-17B, MW-18C, and MW-19C. TBA was detected in 6 of the 16 wells sampled at a concentrations ranging from 28 pg/L (MW-20)to 57 pg/L (MW-9). 4