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California Megional Water Quality Corool Board .� <br /> Central Valley Region Vj <br /> Karl E.Longley,ScD,P.E.,Chair <br /> Arnold <br /> Linda S.Adams Sacramento Main Office Schwarzenegger <br /> Secretaryfor 11020 Sun Center Drive#200,Rancho Cordova,California 95670-6114 Governor <br /> Environmental Phone(916)4643291•FAX(916)464-4645 <br /> Protection http://www.waterbouds.ca.gov/centralvalley EC / r��- D <br /> 5 March 2008 MAR - 6 2008 <br /> ENVIRONMENT HEALTH <br /> Mr. Joe Lentini PERMIT/SERVICES <br /> Shell Oil Products US <br /> 20945 S. Wilmington Ave. <br /> Carson, CA 90810 <br /> REVIEW OF SITE INVESTIGATION WORK PLAN, SHELL CRUDE OIL PIPELINE <br /> RELEASE, HIGHWAY 580 AND BIRD ROAD, SAN JOAQUIN COUNTY <br /> Staff of the Regional Water Quality Control Board, Central Valley Region (Regional Water <br /> Board) has reviewed the 22 February 2008 Site Investigation Work Plan, Shell Pipeline, <br /> Vernalis Site, Interstate 580 at South Bird Road Overpass, Tracy, California (Work Plan) <br /> submitted by Conestoga-Rovers & Associates (CRA) on behalf of Shell Oil Products US <br /> (Shell). The Work Plan was submitted at the request of Granite Construction Company <br /> (Granite), for the purpose of determining the extent of remaining crude oil contamination on <br /> their property (referred to as the Vernalis site in the Work Plan) resulting from a Shell pipeline <br /> leak in April 2007. <br /> The Work Plan proposes a scope of work consisting of drilling twenty-three soil borings at and <br /> around locations where confirmation soil samples collected during the previous site remedial <br /> excavation activities on Granite's property indicated concentrations of total petroleum <br /> hydrocarbons as crude oil (TPHcr) over 500 milligrams per kilogram. The soil borings will be <br /> drilled using a hollow-stem auger drill rig with soil samples collected continuously below 3 feet <br /> below ground surface (bgs) for soil description and possible chemical analysis. For soil <br /> borings located within the footprint of the remedial excavation, soil samples will be collected <br /> and submitted for chemical analysis of TPHcr at the base of the excavation (approximately 9 <br /> feet bgs) and 2 feet below the base of the excavation. For soil borings located outside of the <br /> previous excavation, soil samples will be collected and submitted for TPHcr analysis from <br /> approximately 5 and 9 feet bgs. Soil samples will be analyzed for TPHcr by EPA Method <br /> 8015M. <br /> Regional Water Board Staff concurs with the activities proposed in the Work Plan with the <br /> following conditions and comments. Following drilling, the soil borings should be backfilled <br /> with grout and the soil cuttings retained for disposal. Copies of any additional laboratory <br /> reports and disposal receipts for the soil cuttings should be included with the written report that <br /> details the results of this investigation. In addition, soil impacts previously observed by <br /> Regional Water Board Staff and others indicated that the crude oil spill impacted deeper soil <br /> via pathways that may have consisted of former orchard tree roots or animal burrows. <br /> Although all visually stained soils were removed, the extensions of these preferential pathways <br /> may still represent the locations of residual contamination. Therefore, soil samples should <br /> California Environmental Protection Agency <br /> co Recycled Paper <br />