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r - � <br /> CaliforniVegional Water Quality Cool Board <br /> Central Valley Region <br /> Karl E. Longley,ScD, PE, Chair <br /> Linda S.Adams Arnold <br /> Secretor for Fresno Branch Office Schwarzenegger <br /> Erarironnrenla! 1685 E Street,Fresno,California 93706 Governor <br /> Prolection (559)445-5 116• Fax(559)445-5910 <br /> hupWwww.waterboards ca.govkentralvalley <br /> 3 April 2008 <br /> M. Scott Mansholt <br /> Chevron Environmental Management Company <br /> 6001 Bollinger Canyon Road <br /> Rm K2066 <br /> San Ramon, California 94583-2324 <br /> REQUEST FOR NO FURTHER ACTION, MOUNTAIN HOUSE SITE #1, BYRON ROAD, <br /> MOUNTAIN HOUSE, SAN JOAQUIN COUNTY <br /> Regional Water Board staff has reviewed the 4 January 2008 No Further Action Request <br /> report for Mountain House Site #1 , submitted on behalf of Chevron by Science Applications <br /> International Corporation (SAIC). The project is located near the intersection of Mountain <br /> House Road and Byron Road, northwest of Tracy, in western San Joaquin County. <br /> The historical Old Valley Pipeline (OVP) and Tidewater Associated Oil Company (TAOC) lines <br /> transported heated crude oil from Bakersfield to Richmond refineries beginning in the early <br /> 1900's to the late 1960's. The lines were owned and operated by predecessors of Chevron. <br /> In the 1940's the OVP system was used to transport Bunker C fuel oil from the refineries to <br /> railroad hubs in Tracy. Subsequently, the lines were removed from service in the late 1960's. <br /> It has not been substantiated, but reportedly sections of the historic pipeline(s) may have been <br /> removed. The former OVP and TAOC pipelines transected the southwestern and <br /> northeastern portions of the site, respectively. <br /> In addition to the referenced report, we reviewed 2001 to 2007 soil and groundwater <br /> investigation reports prepared for Chevron by SAIC and other environmental consulting firms. <br /> Initially, the 2001 investigation identified impacted soil and groundwater as the result of crude <br /> oil leaks from the former pipelines. An environmental risk evaluation conducted in 2007 by <br /> SAIC was also reviewed. The risk evaluation summarized laboratory analysis and compared <br /> the results to the Preliminary Remediation Goals *' (PRGs), relevant Environmental Screening <br /> Levels *2 (ESLs), and/or Water Quality Objectives *3 (WQOs) to assess various potential <br /> exposure scenarios for the site constituents of potential concern (COPCs). <br /> The site COPCs is petroleum components that may be found in crude oil include polynuclear <br /> aromatic hydrocarbons (PAHs) and/or benzene, toluene, ethylbenzene and xylenes (BTEX). <br /> *1—Preliminary Remedial Goals; US EPA Region 9, San Francisco, October 2004. <br /> *2- Screening for Environmental Concerns at Sites with Contaminated Soil and Groundwater, Interim Final, San Francisco <br /> RWQCB, February 2005). <br /> *3- The US EPA, "Suggested No Adverse Response Levels", 198Q describes 100 pg/L as the taste and odor water quality <br /> objective (WQO) threshold for diesel in groundwater. <br /> California Environmental Protection Agency <br /> Ca Recycled Paper <br />