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California gional Water Quality Con*l Board <br /> Central Valley Region OF/I <br /> Robert Schneider,Chair <br /> Linda S.Adams Arnold <br /> Secreta ryf or Sacramento Main Office <br /> 11020 Sun Center Drive#20 .Rancho Cordova,California 956706114 Schwovernegger <br /> 0 <br /> Environmental Governor <br /> Protection Phone(916)4643291 •FAX(916)4644645 <br /> http://www.waterbouds.ca.gov/centralvalley <br /> RECEIVED <br /> V���/Q <br /> ED <br /> 2 October 2006 <br /> OCT 5 2006 <br /> ENVIRGNMENT HEALTH <br /> Mr. Jeff Whitworth PERMIT/SERVICES <br /> Shell Oil Products US <br /> 20945 South Wilmington Avenue <br /> Carson, CA 90810 <br /> REVIEW OF 2006 FIRST SEMIANNUAL REPORT, SHELL STOCKTON TERMINAL, 3515 <br /> NAVY DRIVE, STOCKTON, SAN JOAQUIN COUNTY <br /> Staff of the Regional Water Quality Control Board - Central Valley Region (Regional Water <br /> Board) has reviewed the 1 September 2006 Groundwater Monitoring and Remediation Report, <br /> 2006 Semi-Annual Report— 1St and 2"d Quarters (First Semiannual Report) submitted by <br /> Cambria Environmental Technology, Inc. (Cambria) on behalf of Shell Oil Products US (Shell) <br /> for the Shell Stockton terminal located at 3515 Navy Drive in Stockton (site). The First <br /> Semiannual Report describes groundwater monitoring and remediation activities performed <br /> during the first and second quarter 2006. On 25 July 2006, Cambria requested and received a <br /> time extension from 1 August 2006 to 1 September 2006 for submittal of the report. <br /> The First Semiannual Report presents data from the first and second quarter 2006. The <br /> report includes two pages of text, a site vicinity map, two figures exhibiting data from each <br /> quarter, and tabulations of the monitoring schedule, groundwater extraction system mass <br /> removal data, and historical groundwater level, contaminant, flow direction, and gradient data. <br /> The text provides a brief comparison of recent and previous groundwater flow, gradient, and <br /> contaminant concentration data, and states that the plume appears to be stable. Each of the <br /> two data figures presents Total Petroleum Hydrocarbons (TPH) as gasoline and diesel, <br /> benzene, and methyl tertiary butyl ether (MTBE) groundwater data as well as groundwater <br /> elevation data and associated elevation contours. Maximum groundwater contaminant <br /> concentrations during the reporting period are 57,000 micrograms per liter (ug/L) TPH as <br /> gasoline (MW-1); 19,000 ug/L TPH as diesel (MW-15); 14,000 ug/L benzene (MW-15); and <br /> 41,000 ug/L MTBE (MW-1). The report anticipates that groundwater monitoring, remedial <br /> system operation, and an evaluation of monitored natural attenuation (MNA) results presented <br /> by the previous consultant will be performed in the third and fourth quarter 2006. <br /> Regional Water Board staff finds that the First Semiannual Report is deficient in several <br /> aspects. In general, the report is too brief and condensed for a typical semiannual report. <br /> More detailed discussions of contaminant concentration trends and plume stability are <br /> necessary to show that site conditions are understood and are being appropriately addressed <br /> by Shell. Groundwater contaminant concentrations do not appear to be stable as stated in the <br /> report. TPH concentrations are increasing at most wells that were sampled both quarters. <br /> This would be more readily apparent if contaminant concentration versus time graphs were <br /> California Environmental Protection Agency <br /> �a Recycled Paper <br />