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GEOTHASE <br /> ENVIRONMENTAL <br /> ADDENDUM TO <br /> PRELIMINARY ENDANGERMENT ASSESSMENT <br /> Former Haley Flying Service <br /> 21,000 Paradise Road, Tracy <br /> Cal-Site*39070037 <br /> June 23, 2006 <br /> GPE Project No. 474.2 <br /> EXECUTIVE SUMMARY <br /> Reference is made to our original Preliminary Endangerment Assessment (PEA) dated <br /> January 18, 2006 (Geo-Phase Environmental 2006a). The PEA identified the presence of <br /> significant pesticide contamination in the shallow soil in an area near the east end of the <br /> subject site. Two grab groundwater samples collected during the original assessment <br /> contained detectable concentrations of various pesticides. These sample results were, <br /> however, not considered definitive due to suspected cross-contamination of the sampling <br /> equipment from the high concentrations of pesticides in the shallow soil. <br /> Section 2 of the original PEA provides a site description, the background, and status of the <br /> Haley site. Section 5 of the PEA describes the sample results of soil and groundwater <br /> previously collected samples. <br /> Scope of Work <br /> This Addendum describes a series of 6 Power-Probe soil borings that were installed in the <br /> vicinity of the former chemical mixing and loading area, and the adjacent washout pit. <br /> Groundwater samples were collected from the borings and from the on-site domestic water <br /> well (see Figure 2 for boring locations). The samples were tested for the possible presence of <br /> organo-chlorine pesticides. <br /> Sample Analytical Results <br /> The analytical testing documented in the original PEA indicates the soil in the vicinity of the <br /> aircraft loading dock, surrounding loading pad, and the washout pit, is severely contaminated <br /> by a variety of pesticides, mostly of the organo-chlorine group. The bulk of the contaminant <br /> mass consists of the DDT sub-group (DDT, DDD, DDE) and Toxaphene. Other <br /> contaminants include Chlordane, Aldrin, Methoxychlor, and the Endosulfan sub-group. <br /> 2937 Veneman Avenue,Suite B240 Geo-Phase Environmental Inc. Phone: (209)569-0293 <br /> Modesto,Ca 95356 Fax: (209)569-0295 <br />