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California #gionaI Water Quality Con t�l Board <br /> Central Valley Region <br /> Karl E. Longley,SCD,P.E.,Chair <br /> Linda S.Adams 00."Secrempfm Sacramento Main office Arnold <br /> Fnvironmenlal 11020 Sun Center Drive#200,Rancho Cordova.California 956706114 Schwarzenegger <br /> Protection Phone(916)464-3291 •FAX(916)4644645 <br /> Governor <br /> httP://www.wauerboards ca.gov/centralvalley <br /> 25 April 2008 fw� <br /> Mr. Jeff Baker W� Do <br /> Tesoro Companies, Inc. APR 9 e008 <br /> 3450 South 344" Way, Suite 100 <br /> Auburn, WA 98001-5931 ENVIFON�y1ENT HEALTH <br /> PERPIII�;SER'JICES <br /> RESPONSE TO COMMENTS, STOCKTON TERMINALS TECHNICAL COMMITTEE <br /> FACILITIES, PORT OF STOCKTON, SAN JOAQUIN COUNTY <br /> Regional Water Quality Control Board, Central Valley Region (Regional Water Board) staff <br /> reviewed the 28 January 2008 Response to RWQCB Letter Dated June 14 2007 (Response). <br /> SECOR International, Inc. (SECOR) submitted the document on behalf of the Stockton Terminals <br /> Technical Committee (STTC). STTC is comprised of three bulk fuel facilities at the Port of <br /> Stockton (Site) including British Petroleum (BP) (formerly ARCO), Tesoro Petroleum Company <br /> Inc. (Tesoro), and Time Oil Company. <br /> The principal contaminants of concern (CDCs) at the Site include total petroleum hydrocarbons <br /> as gasoline (TPHg), TPH as diesel (TPHd), benzene, toluene, ethylbenzene, and xylenes <br /> (BTEX), tertiary amyl methyl ether (TAME), methyl tertiary butyl ether (MTBE), and tertiary butyl <br /> alcohol (TBA). The Response attributes the off-site migration of petroleum hydrocarbons <br /> primarily to a 1998 spill at the Tesoro site and steeper pre-1997 horizontal gradients, corrects <br /> portions of our summary of the first quarter 2007 groundwater monitoring data, and offers <br /> conclusions regarding the lateral and vertical distribution of COCs emanating from the Site. The <br /> Response includes concentration plots for select wells that show increasing benzene <br /> concentrations in three downgradient, off-site monitoring wells (OW-9C, OW-8D, and OW-3C). <br /> Despite these increasing concentrations, the Response concludes that groundwater monitoring <br /> data do not show that that off-site migration of CDCs is occurring and offers no immediate <br /> remedy for the downgradient migration within the C and D water bearing zones. <br /> Separate phase hydrocarbons (SPH) are typically observed in four on-site monitoring wells <br /> (AR/MW-12A, TO/MW-1, TS-4, and TS/M-2). STTC has utilized SoakeaseTM SPH removal <br /> socks in these wells since 20 September 2002 to remove the SPH. On 2 May 2007, STTC <br /> submitted the Work Plan for Enhanced Bioremediation Study, which proposes injecting a nutrient <br /> solution to clean up fuel hydrocarbons at the BP Site. <br /> The STTC conducts monitoring at the Site pursuant to the requirements of Monitoring and <br /> Reporting Program (MRP) No. R5-2004-0823. SECOR conducted groundwater monitoring and <br /> sampling for the Second, Third, and Fourth quarterly monitoring reports (QMRs) during April, <br /> July, and October 2007, respectively. Sediments underlying the Site are subdivided into four <br /> progressively deeper hydrostratigraphic units referred to as the A Zone, B Zone, C Zone, and D <br /> Zone. In the Fall of 2004, the STTC began operation of two ozone sparge (OS) systems to clean <br /> California Environmental Protection Agency <br /> `p$Recycled Paper <br />