ARCHIVED REPORTS_SITE CHARACTERIZATION REPORT 1999

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7h3adweII&RoIIo Noncarcinogenic HIs of less than one were calculated for construction and landscape workers, and residents. While excess cancer risks for construction and landscape workers were within the acceptable range,the calculated risk for residents was greater than 1E-06. This appears to be driven by the single occurrence of benzo-a-pyrene found at 2BB-1, suggesting that the actual exposure risk should be low. Soil lead concentrations do not appear to represent a potential health hazard. Area 3 No petroleum hydrocarbons, volatile or semivolatile hydrocarbons were detected in any of the soil samples collected from the test pits or test borings. TPH as diesel was detected at 18 mg/kg at 5 feet bgs at monitoring well 3MW-1, located in the northwestern corner of the site. Lead concentrations exceeded 130 mg/kg in 5 soil samples, generally in the top one foot of soil. Concentrations ranged from 200 to 710 mg/kg. Samples with total lead concentrations of 630 and 710 mg/kg were analyzed for soluble lead using the TCLP test. No soluble lead was ' detected. Using the STLC test, 24 mg/l of lead was leached from the sample with total lead of 630 mg/kg. These findings suggest that a soil management plan designed to deal with lead in the tsoil may be required to develop the site, and that soil excavated and removed from the site may require handling as a hazardous waste. Total mercury at 9.1 mg/kg was detected in one soil sample (3TP-1) at 1 foot bgs. Because this exceeded the EPA Residential Preliminary Remediation Goal of 5.5 mg/kg, the sample was analyzed for soluble mercury using the TCLP method. A total of 0.046 mg/l soluble mercury twas detected. Groundwater is minimally impacted by petroleum hydrocarbons. TPH as gasoline was detected at 0.07 mg/l at well MW-1-3. BTEX compounds were all less than 0.001 mg/1. No significant ' metals concentrations were detected. 1 16 25970119.DGD 13 December 1999