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California l�;ional Water Quality Cont., Board <br /> Central Valley Region <br /> Karl E. Longley,SCD, P.E.,Chair <br /> Linda S.Adams 11020 Sun Center Drive i#200, Rancho Cordova.Califon 7 61 14 Arnold <br /> Secretory for ,y�r���/J��� Schwarzenegger <br /> Phone(916)464-3291 •PAX(916)464-4��� '-�ll� � vY U <br /> f_mvronmewnal http:/hvNv",waterboards ca.gov/centralvall�d�� �� Governor <br /> Protecoo+r <br /> 16 January 2009 JAN 2 Q 2009 <br /> ENVIRC)&HENT HEALTH <br /> PERPA T/SERVICES <br /> Mr. John MacLeod <br /> Chevron Environmental Management Company <br /> 6001 Bollinger Canyon Road, Room K2276 <br /> San Ramon, CA 94583 <br /> 2008 ANNUAL GROUNDWATER MONITORING REPORT, CHEVRON CORRAL HOLLOW <br /> AND GRANT LINE ROADS, TRACY, SAN JOAQUIN COUNTY <br /> California-Regional Water Quality-Control Board, Cen-tra-Valley Region (Regional Wafer <br /> Board) staff reviewed the 19 December 2008 2008 Annual Groundwater Monitoring Report <br /> (Report) prepared by ARCADIS on behalf of Chevron Environmental Management Company <br /> (Chevron) for the Corral Hollow and Grant Line Roads Site in Tracy (Site). <br /> Chevron operates an underground, refined fuel pipeline at the Site that runs underneath Grant <br /> Line Road. The Site is at the intersection.of Corral Hollow and Grant Line Roads and is <br /> surrounded by mixed residential and commercial development. In 1987, about 870 gallons of <br /> refined fuel were released from the pipeline during installation of dewatering wells by the City <br /> of Tracy. Chevron repaired the pipeline, excavated about 100 cubic yards of soil, and <br /> recovered about 840 gallons of fuel. In 1997, Chevron operated a dual phase extraction <br /> system at the Site and subsequently destroyed all but six monitoring wells. Chevron continues <br /> to collect semi-annual groundwater samples from the six remaining monitoring wells in <br /> accordance with Monitoring and Reporting Program No. R5-2006-0804 (MRP). <br /> On 17 November 2008, Chevron conducted the fourth quarter 2008 groundwater monitoring <br /> event. Groundwater flow was to the east, and depth to water was about nine feet below <br /> ground surface (bgs). Maximum concentrations of total petroleum hydrocarbons as gasoline <br /> (TPHg), TPH as diesel (TPHd), and benzene were 970 micrograms per liter (pg/L), 1 ,400 pg/L, <br /> and 1_0 pg/L,, respectively. Chevron also analyzes Site wells for polynuclear aromatic <br /> hydrocarbons (PAHs). Naphthalene was detected in three wells at a maximum concentration <br /> of 56 pg/L. Pyrene was detected in two wells at a maximum concentration of 0.10 pg/L. <br /> MW-6 also contained acenaphthene, fluorene, anthracene, and fluoranthene at concentrations <br /> of 0.15 Ng/L, 0.27 pg/L, 0.084 pg/L, and 0.022 pg/L, respectively. <br /> Our comments are included below: <br /> 1. The MRP states that the Annual Report needs to include a discussion of the long-term <br /> trends in the concentrations of the pollutants in groundwater monitoring wells. The <br /> Report does not include any discussion of the long-term trends of concentrations. The <br /> MRP also requires Chevron to include a table of the well construction details for all Site <br /> wells. The Report does not include this table. Future monitoring reports need to <br /> include all information required by the MRP. <br /> California Environmental Protec,ion Agency <br /> Vp' Recirled Paper <br />