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k'q KLEINFELDER <br /> water. The following exposure pathways were accounted for in the PRG calculation for soils <br /> assuming residential land use: <br /> • Ingestion <br /> • Inhalation of particulates <br /> • Inhalation of volatiles <br /> • Dermal (skin) absorption <br /> For the inhalation pathways, volatilization factors and particulate emission factors are used to <br /> estimate exposure due to emissions from soil to air. For the dermal absorption pathway, a 10% <br /> skin absorption factor was used to calculate the PRGs for the constituents of concern at the site. <br /> This factor assumes the dermal dose is equal to an adult's ingestion dose. <br /> If contaminant concentrations at the subject site exceed the estimated PRG values and the <br /> exposure pathways used to calculate those PRGs are inappropriate for the site, additional site <br /> evaluations, such as an evaluation of background levels, supplementary sampling and <br /> calculations using site-specific data may be necessary. <br /> The residential soil PRGs were evaluated for DDE for the site. <br /> Constituent ConcentrationRange PRG <br /> Detected at the Site <br /> 4,4'-DDE 7.32 to 25.5 µg/kg 1.3 mg/kg (1,300 µg/kg) <br /> The PRG exposure pathways used for soil are appropriate for the project site and the PRG values <br /> are orders of magnitude higher than the reported contaminant levels in the surface soils. <br /> Therefore, it appears that additional evaluations or remedial action will not be necessary for the <br /> 4,4'-DDE concentrations detected. <br /> 6.2 BUILDING AREA SOIL SAMPLING <br /> Two exploratory soil borings were advanced within the building area of Blossom Ranch (See <br /> Plate 3). The borings were drilled in suspect UST areas noted from a geophysical survey and <br /> from Kleinfelder's field observations. Soil samples were collected at 5 foot intervals beginning <br /> at 5 feet for logging purposes and potential chemical analysis. Boring B-1 was located southeast <br /> of a cinder block building and boring B-2 was located north of a hulling shed. Both borings were <br /> advanced to a total depth of approximately 30 bgs. Groundwater was not encountered during the <br /> drilling activities. <br /> During the drilling operations no odors or discoloration were present in soil samples collected <br /> from borings B-1 and B-2. Organic vapor readings for twelve soil samples collected from the <br /> two borings ranged from 4.3 to 7 parts per million vapor. <br /> 20-3712-08.E02/2018R1090 Page 12 of 17 <br /> ©1998,Kleinfelder,Inc. December 23, 1998 <br />