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DRAFT <br /> 1 <br /> ArAr=A <br /> ion resulted in HIs greater than l for the construction <br /> he noncarcinogenic evaluatdent. The elevated HIs for these <br /> worker, landscape maintenance worker, and resi <br /> are primarily due to 2-methyl naphthalene in soil. It should be noted that <br /> treceptors <br /> toxicity data for naphthalene are used as a surrogate for 2-methyl naphthalene and may <br /> result in a conservative estimate of noncarcinogenic hazard. <br /> 1within the acceptable risk range of 1 E-04 to 1 E-06 for the <br /> Excess cancer risks were well <br /> construction worker, commercial/industrial worker, and landscape maintenance worker <br /> Excess <br /> risk <br /> cancer risk was higher than 1E-04 for the resident. Excess cancer sk at <br /> t a 2A <br /> was primarily driven by the presence of arsenic in soil. Further evaluation of natural <br /> background arsenic concentrations in the Stockton area should be considered prior to <br /> implementing remedial actions at Area 2A. <br /> The representative Area 2A lead concentration of 93 mg/kg in soils was less than the <br /> and the industrial <br /> child receptor-based lead in soil target concentration(485 mg/kg) <br /> ' receptor-based lead in soil target concentration(5,486 mg/kg). Lead in Area 2A soils <br /> ranged from 4 mg/kg to 130 mg/kg. Consequently,the soil lead concentrations in Area <br /> 2A do not appear to represent a potential health hazard. <br /> Area 2B <br /> In Area 2B the noncarcinogenic HIs were less than one for all receptors evaluated. <br /> Excess cancer risk <br /> estimated for the construction worker and landscape maintenance <br /> worker was within the acceptable range of risks for non-residential site use of IE-04 to <br /> 1E-06. For the resident, the summed estimated total lifetime excess cancer risk was <br /> greater than 1E-06,which is the acceptable excess cancer risk for the residential scenario. <br /> driver of carcinogenic risk appears to be the presence of benzo(a)pyrene in <br /> The primary pp <br /> soil,which was detected in one soil sample at 1,020 µg/kg at a depth of 1.0 foot. The soil <br /> data suggests that there may be a localized area of PAHs in Area 2B. <br /> ' SOMA 99-2218 <br /> 20 12/10/99 <br />