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California Regional Water Quality Control Board <br /> Central Valley Region <br /> Robert Schneider,Chair <br /> Alan C.Lloyd,Ph.D. Arnold <br /> Secretaryfor Fresno Branch Office Schwarzenegger <br /> Environmental 1685 E Street,Fresno,California 93706mor <br /> Protection (559)445-5116•Fax(559)445-5910 �r �,, I I ll <br /> http://www.waterboards.ca.gov/centralvalley <br /> NOV 2 1 2005 <br /> 18 November 2005 ENVIRONMENT HEALTH <br /> PERMIT/SERVICES <br /> M. Scott Mansholt <br /> Chevron Environmental Management Company <br /> 6001 Bollinger Canyon Road, Rm K2066 <br /> San Ramon, California 94583-2324 <br /> REVISED SITE CLOSURE REQUEST,POMBO PROPERTY, 1755 WEST 11'STREET, TRACY, <br /> SAN JOA QUIN COUNTY <br /> Regional Board staff has reviewed the referenced document, dated 13 October 2005, submitted on behalf <br /> of Chevron by Science Applications International Corporation (SAIC). The revised report provides a <br /> detailed discussion to support a No Further Action request in accordance with "Appendix A Reports, Tri- <br /> Regional Board Staff Recommendations for Preliminary Investigation and Evaluation of Underground <br /> Tank Sites", dated 14 April 2004. <br /> The Revised Site Closure Request report addressed comments outlined in our 3 August 2005 <br /> memorandum where Regional Board staff requested additional information, documentation, and/or <br /> clarification for deficiencies of certain items discussed in the initial closure report dated 14 June 2005. <br /> Based on our review of the comments in response to the deficiencies outlined in our August report, the <br /> following items have been adequately addressed in the Revised Site Closure Request: <br /> • Recent and historical analysis for metals constituents in crude oil of samples from several Old <br /> Valley Pipeline(OVP) sites, including Pombo, are below Preliminary Remediation Goals (PRGs) <br /> provided by the United States Environmental Protection Agency(US EPA), Region IX. <br /> Comparison of the metals analytical results of the OVP crude oil to the PRGs, indicated that the <br /> concentrations reported, occasionally with the exception of arsenic, were non detect(ND) or less <br /> than the respective PRGs. Arsenic values in soil at OVP sites occasionally exceed the PRG for <br /> arsenic in soil, but are consistent with documented studies of background arsenic concentrations <br /> reported in California soil described in"Background Concentrations of Trace Metals and Major <br /> Elements in California Soils", a Kearny Foundation Special Report, dated March 1996, <br /> completed by DTSC and UC-Riverside. Based on the data, the San Joaquin Valley Crude Oil <br /> transported in the OVP, is not likely a source of metals at the Pombo property. <br /> • The Soil Management Plan is provided in Appendix F. <br /> • Previous Environmental Activities adequately summarizes impacted soil and groundwater; <br /> Figure 4—Hydrocarbon Distribution in Groundwater, has been corrected. <br /> California Environmental Protection Agency <br /> ��Recycled Paper <br />