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California&gional Water Quality CorSol Board <br /> l\j Central Valley Region a <br /> Katherine Hart,Chair ✓ <br /> Linda S. Adams Secremryfor 11020 Sun Center Drive#200,Rancho Cordova,California 956746114 Arnold <br /> vi <br /> EnnvironmSchwarzeneggental Phone(916)464-3291 •FAX(916)464-4645 Governor <br /> Proleclion http://www.waterboards.co.gov/centralvalley <br /> 16 June 2010 �j �� C FEED <br /> JL!!V I 'l LUIII <br /> Mr. Jeff Baker ENVIRONMENT HEALTH <br /> Tesoro Companies, Inc. PERMIT SER' ICES <br /> 3450 South 344'h Way, Suite 100 <br /> Auburn, WA 98001-5931 <br /> FIRST QUARTER 2010 SITE STATUS, GROUNDWATER MONITORING AND <br /> REMEDIAL SUMMARY REPORT, STOCKTON TERMINALS TECHNICAL <br /> COMMITTEE FACILITIES, PORT OF STOCKTON, SAN JOAQUIN COUNTY <br /> Regional Water Quality Control Board, Central Valley Region (Central Valley Water <br /> Board) staff reviewed the 30 April 2010 First Quarter 2010 Site Status, Groundwater <br /> Monitoring and Remedial Summary Report(First QMR) submitted on behalf of the <br /> Stockton Terminals Technical Committee (STTC) by Stantec Consulting Corporation <br /> (Stantec). STTC is comprised of three bulk fuel facilities at the Port of Stockton <br /> including British Petroleum (BP, formerly ARCO), Tesoro Petroleum Company Inc. <br /> (Tesoro), and Time Oil Company (TOC). These terminals are collectively referred to as <br /> the Site. <br /> The principal contaminants of concern (COCs) at the Site include total petroleum <br /> hydrocarbons as gasoline (TPHg), TPH as diesel (TPHd), benzene, toluene, <br /> ethylbenzene, and xylenes (collectively BTEX), tertiary amyl methyl ether (TAME), <br /> methyl tertiary butyl ether (MTBE), and tertiary butyl alcohol (TBA). Methylene blue <br /> active substances (MBAS) also has been observed in groundwater after monitoring for <br /> this constituent began in March 2009 following a November 2008 release of fire <br /> suppression foam from the BP loading rack. <br /> The STTC conducts monitoring at the Site pursuant to Monitoring and Reporting <br /> Program (MRP) No. R5-2004-0823. Stantec conducted groundwater monitoring for the <br /> first quarter of 2010 between 1 and 5 February 2010. Sediments underlying the Site are <br /> subdivided into four progressively deeper hydrostratigraphic units classified as the <br /> A Zone, B Zone, C Zone, and D Zone. During the first quarter, depth to groundwater <br /> ranged from about zero to 11 feet below ground surface (bgs). Groundwater flowed <br /> toward the southeast in all the zones at gradients ranging from 0.001 to 0.007 feet per <br /> foot. The historically downward vertical gradients between the four hydrostratigraphic <br /> units continued to be downward during the first quarter. <br /> Measurable separate phase hydrocarbons (SPH) have historically been observed in up <br /> to 20 wells. No measurable SPH was observed in wells during the first quarter, but SPH <br /> sheen was observed in TS/RW-1. <br /> California Environmental Protection Agency <br /> �a Recycled Paper <br />