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California legional Water Quality Conte Board <br /> ` I Central Valley Region ,NKj J <br /> Karl E. Longley,ScD, P.E.,Chair <br /> Arnold <br /> Linda S.Adams Sacramento Main Office <br /> Schwarzenegger <br /> Secretaryfor 11020 Sun Center Drive#200,Rancho Cordova,California 95670-6114 <br /> GovernorEnvironmental <br /> Phone(916)464-3291 •FAX(916)464-4645 <br /> Protection hnp://www.waterboards.ca.gov/centralvalley <br /> G <br /> FCr IFt 10 <br /> 14 June 2007 <br /> JUN 1 6 2001 <br /> Mr. Jeff Baker ENVIRONMENT HEALTH <br /> Tesoro Companies, Inc. PERMIT/SERVICES <br /> 3450 South 3441h Way, Suite 100 <br /> Auburn, WA 98001-5931 <br /> QUARTERLY GROUNDWATER MONITORING REPORTS, STOCKTON TERMINALS <br /> TECHNICAL COMMITTEE FACILITIES, PORT OF STOCKTON, SAN JOAQUIN COUNTY <br /> Regional Water Quality Control Board, Central Valley Region (Regional Water Board) staff <br /> reviewed the: <br /> 31 January 2007 Fourth Quarter & Annual 2006 Groundwater Monitoring, and <br /> Remedial Summary Report (Annual Report), <br /> 1 May 2007 First Quarter 2007 Quarterly Groundwater Monitoring, and Remedial <br /> Summary Report (First QMR). <br /> SECOR International, Inc. (SECOR) submitted the documents on behalf of the Stockton <br /> Terminals Technical Committee (STTC). STTC is comprised of three bulk fuel facilities at the <br /> Port of Stockton (Site) including British Petroleum (BP) (formerly Arco), Tesoro Petroleum <br /> Company Inc. (Tesoro), and Time Oil Company. The STTC conducts monitoring at the Site <br /> pursuant to the requirements of Monitoring and Reporting Program (MRP) No. R5-2004-0823. <br /> SECOR conducted groundwater monitoring and sampling for the Annual Report during <br /> October 2006, and for the First QMR during January 2007. Since September 2004, two ozone <br /> sparge (OS) systems have been operated to contain the contaminant plume. <br /> Sediments underlying the Site are subdivided into four progressively deeper hydrostratigraphic <br /> units referred to as the A Zone, B Zone, C Zone, and D Zone. During October, depth to <br /> groundwater (DTW) measurements ranged from about 3 to 11 feet below ground surface <br /> (bgs). The A and B zones showed localized water table mounding at well PS/WC-1 S/M and <br /> radial inward flow at well SP/WC-1S/M, with gradients ranging from about 0.004 foot per foot <br /> (ft/ft) to 0.018 ft/ft. In the C and D zones, groundwater flowed generally to the east at gradients <br /> ranging from 0.003 to 0.007 ft/ft. The direction of the vertical gradient at the Site is <br /> predominantly downwards between the four hydrostratigraphic units. During 2006 the <br /> downward vertical gradients ranged from 0.699 ft/ft between the B and C zones to 0.00 ft/ft. <br /> The principal contaminants of concern (CDCs) include total petroleum hydrocarbons as <br /> gasoline (TPHg), TPH as diesel (TPHd), benzene, toluene, ethylbenzene, and xylenes <br /> (BTEX), tertiary alcohol methyl ether (TAME), and methyl tertiary butyl ether (MTBE). The <br /> highest COC concentrations typically underlie the BP and Time Oil facilities. As reported in the <br /> California Environmental Protection Agency <br /> Qo4 Recycled Paper <br />