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Site Characterization:Clover'*Wle School,51 East Beverly Place, Tracy, CA. '�'�' Page 2 ,. the boring at a depth of 13 f1. BGS. Kleinfelder's boring log is included in Appendix A. Analysis of the sample of groundwater recovered by Kleinfelder found that it contained "other hydrocarbons" at a concentration of 250 µg/L, no detectable benzene, toluene at 90 gg/L and total xylene isomers at 450 Vg/L. No analysis was made for ethyl benzene. Kleinfelder staff recovered three soil samples from their boring but the report does not positively identify the depths from which soil samples were recovered. Approximate depths of 5, 10 and 15 ft can be inferred from the context of the report's description of the scope of work performed. It is not clear from the available records whether the soil samples recovered by Kleinfelder were analyzed within the acceptable holding period of 14 days for samples to be analyzed for volatile organic compounds (i.e. shortly after the AW time they were recovered on September 17, 1985), or at some time after the December, 1985 date when the SJCPHS requested that such analyses be made. As is shown in the tabulation in Appendix A, the analyses performed for Kleinfelder found no detectable concentration of benzene, toluene or total xylene polymers in the soil samples from the boring drilled "adjacent to the V. tank pit." (As was the case for the sample of groundwater, no analyses were made for the presence of ethyl benzene in the sample.) However, "other hydrocarbons" at concentrations ranging from 2 to 3 mg/Kg were detected in these soil samples. Analyses for the total lead in the soil samples found this metal to be present in concentrations ranging from 7 to 13 mg/L. The latter concentrations are well within the range for naturally occurring lead in soils from the Tracy area. (The San Joaquin Company Inc., 2000) 1.3.2 Work Plan for Extended Site Characterization At the request of the SJCPHS, the Tracy USD prepared a work plan for an extended 'investigation to further characterize the former site of the " underground storage tank at the Alfred Clover Middle School. The scope of work included drilling of two borings, recovery and analysis of soil and groundwater samples and areceptor-well survey. The work plan was submitted to the SJCPHS on May 18, 2000 (Tracy Unified School District, 2000), and it was approved by that agency. low In June 2000, the Tracy USD retained The San Joaquin Company Inc. to implement the work plan. The results of the investigation are reported herein 2.0 GEOLOGY AND HYDROGEOLOGY The subject property and the surrounding area are situated on level terrain on the distal, northeastern slope of an alluvial fan. The underlying alluvial soils sic