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From Science to Solutions- <br /> HPP-BTR MP#Various <br /> Various Tasks <br /> Reports <br /> DCN:C20-SAI-Various-01-11922 <br /> May 25, 2007 <br /> Mr. M. Scott Mansholt <br /> Chevron Environmental Management Company <br /> 6001 Bollinger Canyon Road,K2072 <br /> P.O. Box 6012 <br /> San Ramon, CA 94583-0712 <br /> Subject: Presentation of Additional Metals Evaluation <br /> Historical Pipeline Portfolio <br /> Dear Mr. Mansholt: <br /> On behalf of Chevron Environmental Management Company(CEMC), Science Applications <br /> International Corporation(SAIC) is pleased to submit this report of our evaluation of metals at sites <br /> associated with Chevron's Historical Pipeline Portfolio (HPP). The HPP is comprised by the former <br /> crude oil-containing Old Valley Pipeline(OVP) and the Tidewater Associated Oil Company(TAOC) <br /> pipelines, including sites with petroleum-affected soil. Metals data were first submitted in association <br /> with the Technical Approach to Site Evaluation and Decision-Making, Historical Pipeline Portfolio, <br /> Central Valley Region (referred to as the Consistent Technical Approach).' CEMC wanted to further <br /> assess whether the metals concentrations in the petroleum-affected soil at HPP sites are above background <br /> concentrations, and this report transmits an updated and substantially expanded metals evaluation. <br /> INTRODUCTION <br /> The initial evaluation of metals data involved 11 soil samples from HPP sites and six oil samples, either <br /> reference samples of San Joaquin Valley crude oil(the type of oil transported through the pipelines)or <br /> samples of oil from monitoring wells or other sources at HPP sites. Since then, an additional 55 soil <br /> samples from HPP sites have been analyzed, as have three new samples of oil from monitoring wells at <br /> HPP sites. All metals results(old and new) are presented in Table 1. Where available,the concentrations <br /> of total petroleum hydrocarbons as quantified as crude oil(TPHc)for the samples are included in the <br /> table. Background metals concentrations from two studies are also shown in the table 2,3. Finally,health- <br /> based soil screening levels (SSLs)from the U.S. Environmental Protection Agency(EPA), San Francisco <br /> Bay Regional Water Quality Control Board, and California Environmental Protection Agency(Cal/EPA) <br /> Department of Toxic Substances Control(DTSC)are shown in the table for comparative purposes. <br /> 1, Geomatrix Consultants,Inc.,2005. Technical Approach to Site Evaluation and Decision-Making,Historical Pipeline <br /> Portfolio, Central Valley Region. February. <br /> 2. Bradford,et al., 1996. Background concentrations of trace and major elements in California soils.Kearney Foundation <br /> Special Report,University of California,Riverside,pp. 1-52. March. <br /> 3. Lawrence Berkeley National Laboratory, 1995. Protocol for Determining Background Concentrations of Metals in Soil at <br /> Lawrence Berkeley National Laboratory(LBNL).University of California. August. <br /> Science Applications International Corporation <br /> 1000 Broadway I Suite#675/Oakland,CA 946071 /tel:(510)433-0835/fax:(510)446-7919 1 saic.com <br />