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Decision Rule: <br /> If OCP concentrations in the proposed soil samples contain OPCs at concentrations that suggest a <br /> significant release has occurred additional assessment including step-out borings and deeper soil <br /> samples may be warranted. <br /> 1.5 Project Time Line <br /> A proposed schedule for the Tracy Corners Shopping Center Site Characterization is presented in Appendix <br /> D. <br /> 2.0 GEOLOGY AND HYDROGEOLOGY <br /> Based on borings advanced during the January 13, 2015 investigation, the underlying subsurface consists <br /> predominantly of brown, dense, damp clay with some medium sand (CL) from the ground surface to <br /> approximately 10 feet bgs. At 10 feet bgs, the subsurface consists predominantly of brown and red, well- <br /> graded wet gravels (GW) or fine to medium grained silty sand (SP). Groundwater was encountered during <br /> this investigation at approximately 10 feet bgs. Groundwater was also encountered at approximately 10 to <br /> 12 feet bgs during the May 21, 2015 groundwater sampling. <br /> Based on review of the State Water Resources Control Board GeoTracker database, a leaking underground <br /> storage tank site is located at 3425 North Tracy Boulevard and immediately northwest and across Clover <br /> Road from the subject property. A January 20, 2005 report prepared by URS Corporation Americas on <br /> behalf of the Atlantic Richfield Company contained site specific groundwater analytical data and <br /> groundwater gradient data from 1988 to December 2004. The groundwater gradient was variable <br /> however, the predominant groundwater gradient was to the northeast typically at 0.004 feet per foot. <br /> 3.0 PROJECT DATA QUALITY OBJECTIVES <br /> Data quality objectives (DQOs) are quantitative and qualitative statements that specify the quality of the <br /> data required to support decisions during the project. The main objective is to ensure that the data <br /> collected are of sufficient quality and quantity to support remedial decision-making. Therefore, this <br /> project dictates sampling and analytical methods and QA/QC procedures to be followed. Appendix A <br /> contains the project specific QA/QC Plan and contains the field documentation forms that will be used <br /> during the investigation. <br /> The objectives for data collection are summarized below: <br /> • Ensure that data collection and measurement procedures are standardized among all <br /> participants; <br /> Sampling and Analysis Plan <br /> Tracy Corners Shopping Center <br /> 3225 North Tracy Boulevard <br /> Tracy,California 95376 <br /> Partner Project Number SM14-129814 <br /> Docket Number HAS-VCA 14/15-108 <br /> August 15,2016 <br /> Page 9 <br />