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* i <br /> Groundwater Monitoring <br /> Report for the Semiannual <br /> ARCADIS Period from January 1 <br /> through June 30,2012 <br /> Lincoln Center,Stockton, <br /> California <br /> sample was collected in laboratory-provided sample containers.All groundwater <br /> samples were stored in an Ice-chilled cooler for transportation to the laboratory under <br /> chain-of-custody protocol. <br /> Duplicate, trip blank,and field blank samples were also collected for QA/QC purposes. <br /> Field activities were documented using the appropriate field forms, including sample <br /> labels, chain-of-custody forms,groundwater sampling forms,and cooler receipt forms. <br /> The standardized field documentation helps to maintain the integrity of field procedures, <br /> including sample collection. <br /> 2.3 Groundwater Sample Analytical Results <br /> The groundwater and QA/QC samples collected during the reporting period were <br /> analyzed for VOCs by Alpha using EPA Method 82608(8260 compound list). <br /> Laboratory analytical data sheets(including the QA/QC samples)for this monitoring <br /> event are available upon request.The laboratory reporting limits for the VOCs analyses <br /> are presented in Appendix A. <br /> 2.3.1 Hazardous Substances <br /> Groundwater sample analytical results are summarized in Tables 2 and 3. Hazardous <br /> Substances data for the A-zone and B-zone wells are presented on Figures 6 and 7, <br /> respectively. The estimated extent of PCE and total Hazardous Substances <br /> contamination in the A-zone aquifer is shown on Figures 8 and 9, respectively.Similarly, <br /> the estimated extent of PCE and total Hazardous Substances contamination in the <br /> B-zone aquifer is presented on Figures 10 and 11,respectively. <br /> The following is a summary of laboratory results for Hazardous Substances: <br /> • PCE was detected in eight monitoring wells.The highest concentration of PCE <br /> (6,000 micrograms per liter[pgA])was detected in the sample collected from <br /> MW-215B. <br /> • TCE was detected in 13 monitoring wells.The highest concentration of TCE <br /> (200 pg/1)was detected in a sample collected from MW-121A-U. <br /> • Cis-1,2-DCE was detected in 12 monitoring wells.The highest concentration of <br /> cis-1,2-DCE(710 pg/1)was detected in a sample collected from monitoring well <br /> MW-124A-L. <br /> �r wcw�cwhsuf�moe>wnoe 6 <br />