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The soil sample reported to contain organic lead was subsequently analyzed for total lead by EPA method 6010 and volatile organic compounds (VOCs)by EPA method 8260 (GC/MS). Total lead was reported in the sample at a concentration of 29.0 mg/kg. The 8260 analysis included a mass spectrophotometer library search for organic lead compounds. No VOCs or organic lead compounds were reported in the soil sample. The organic lead result was reported by the Department of Health Services Leaking Underground Fuel Tank Manual (DHS LUFT)method analysis. However, organic lead compounds may not have been detected by the DHS LUFT method. The lead detected by organic lead analysis may have been inorganic lead. This is based on the following: • Organic lead compounds were not detected by GC/MS analyses with detection capability below the concentrations reported by the DHS LUFT method. • It is unlikely that organic lead compounds are still present from historical releases of gasoline at the site. Tetraethyl lead and tetramethyl lead are unstable in the natural environment. The half-life range for tetraethyl lead is 0.077 to 0.308 years (Howard et al., 1991). Further, sources for organic lead (gasoline)have not been present at the site since for at least 1988 (Michael Robinson, Caltrans, 2001, personal communication). The groundwater grab sample collected from boring HP-2 was reported to contain TPHg that was characterized as weathered at a concentration of 0.083 mg/1 (Table 3). This sample was also reported to contain benzene at 0.00086 mg/l, toluene at 0.00099 mg/l, ethylbenzene at 0.00081 mg/l, and xylenes at 0.0018 mg/1. All reported concentrations were below drinking water Maximum Contaminant Levels (MCLS; CVRWQCB, 2000). The soil and groundwater data are interpreted to indicate that a release of motor vehicle fuels may have occurred on the parcel at the southwest corner of the intersection. Further investigation should be conducted on that parcel and within Caltrans right of way to investigate impacts from the interpreted release. SacDP-N:IrnncjpllProjects18118212641ReporrV20 Au in repon.doc 4-6 5111101