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Page 12 Cabral-McAdams Property October 16,2006 Job No. 1828-092.02 established California Human Health Screening Levels (CHHSLs) for a number of chemicals of concern; however, the list of chemicals found on the CHHSL list is not as comprehensive as the EPA's PRG list of chemicals. The concentrations listed on the EPA-PRG and CHHSL listings are considered to be conservative and are generally used as a tool for decision making and are not official regulatory "cleanup standards". In general, concentrations below the corresponding EPA-PRGs and CHHSLs can be assumed to not pose a significant threat to human health and the environment. However, additional evaluation and/or remedial response can be considered at sites where a chemical is present at concentrations above the corresponding EPA-PRGs and CHHSLs. As indicated earlier in this report, the primary contaminants of concern on the subject property are arsenic, lead, and the organochlorine pesticides DDT and dieldrin. Additional metals and organochlorinated pesticides were identified in soils on the subject property at concentrations above laboratory reporting limits; however, our comparisons with established EPA-PRGs and CHHSLs for these analytes indicate that the concentrations detected are below the mentioned screening values. On June 30, 2006 representatives for the subject property, the DTSC, Kimball Hill Homes, and Raney Geotechnical, Inc. participated in a Scoping Meeting to discuss the target clean-up concentrations for DDT, dieldrin, arsenic, and lead in soils on the property. Representatives from the DTSC indicated that a concentration of 125 mg/kg for lead in residential soils is to be considered an appropriate clean-up level for the subject site. The DTSC also indicated that a concentration of 1.6 mg/kg for DDT and a concentration 0.03 mg/kg for dieldrin (values equivalent to the established PRG concentrations of these analytes in soils for residential sites) are to be considered appropriate clean-up levels for soils on the subject site. A concentration 10.0 mg/kg for arsenic was established as an appropriate clean-up level for the subject site; the rational for a 10.0 mg/kg clean-up goal for arsenic is contained in published document titled Naturally Occurring Concentrations of Inorganic Chemicals in Ground Water and Soil at California Air Force Installations presented in Appendix C. We have compared the analytical data from each area at the subject site to the above- described clean-up goals for the property. The results/evaluation for each area is discussed separately below. Locations of soil samples that contained chemicals of concern at concentrations above the clean-up levels are shown in blue on Plates 3 through 6. ORCHARD AREAS None of the tested soil samples from the orchard areas contained concentrations of lead, arsenic, or the organochlorinated pesticides 4,4'-DDT above established target clean-up concentrations for the subject site. AREA A Arsenic and dieldrin were detected in surface soils in Area A at concentrations above the target clean-up concentrations for these analytes. Dieldrin was detected above the target