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Stantec Consulting Corporation <br /> ( � 3017 Kilgore Road Suite 100 <br /> Rancho Cordova CA 95670 <br /> Tel: (916)861-0400 <br /> Fax: (916)861-0430 <br /> Stantec <br /> April 30, 2010 <br /> File: 18572192.200.011 <br /> Mr. Brian Taylor <br /> California Regional Water Quality Control Board <br /> Central Valley Region <br /> 11020 Sun Center Drive, #200 <br /> Rancho Cordova, California 95670 <br /> Reference: First Quarter 2010 Site Status, Groundwater Monitoring and Remedial <br /> Summary Report <br /> Stockton Terminals Technical Committee Facilities <br /> Port of Stockton <br /> Stockton, California <br /> Dear Mr. Taylor: <br /> On behalf of the Stockton Terminals Technical Committee (STTC), Stantec Consulting Corporation <br /> (Stantec) submits this report summarizing first quarter 2010 project activities at the site referenced <br /> above (Site). The work was performed in accordance with California Regional Water Quality <br /> Control Board - Central Valley Region's (RWQCB) Monitoring and Reporting Program (MRP) No. <br /> R5-2004-0823, which is summarized in Table 1 and included in Appendix A. This report presents a <br /> site background (Appendix B), groundwater elevation and analytical data, a discussion of <br /> groundwater analytical trends, and the status of remediation for first quarter 2010. <br /> 1.0 EXECUTIVE SUMMARY <br /> Stantec conducted first quarter 2010 groundwater monitoring and sampling on February 1 <br /> through 5, 2010. Overall groundwater hydrocarbon concentration trends appear stable to <br /> decreasing with long-term decreasing concentration trends apparent in many wells. The ozone- <br /> injection monitoring program indicates the East and West remedial systems are effectively <br /> controlling off-site migration of petroleum hydrocarbons. Compliance analyte concentrations are <br /> reduced from historical (pre-system installation) averages, some by several orders of magnitude, <br /> and were below reporting limits in all trigger wells. The highest dissolved hydrocarbon <br /> concentrations continue to be located in or near tank farm areas of terminal facilities. Plume <br /> geometry was generally consistent with previous sampling events. No measurable separate phase <br /> hydrocarbons (SPH) were observed in any of the wells, although an SPH sheen was observed in <br /> well TS/RW-1. <br /> Stantec operates two ozone-injection systems (East and West Systems) at the site, which are both <br /> currently operational. Since startup of the systems (2004), results from wells within and <br /> downgradient of the treatment arrays have documented significant concentration decreases. Since <br /> the West System was started, total petroleum hydrocarbons as gasoline (TPHg), benzene and <br /> methyl tertiary butyl ether (MTBE) concentrations in treatment zone well TS/MW-1A decreased by <br />