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. Ms Margaret Lagroto August 11,2004 Subsurface Assessment Rep Project No 2033-15600-01 Joe's Truck Plaza, 15600 South Harlan Road,Lathrop,CA Page 8 Depths to the water table (phreatic surface) calculated from the PPDT's ranged from 7 73 to 15 64 feet bgs (Table 3) The variation in calculated water depth may be the result of the PPDT's not running completely to ttoo These calculated water depths appear to agree with the depth to water measured in newly installed well MW-7 (8 89 feet bgs) on May 25, 2004 (immediately prior to development), and with historical depth to water levels measured in the existing monitoring well network Soil Analytical Results TPHG, TPHD, BTEX, TAME, DIPE, ETBE, TBA, EDB, 1,2-DCA, ethanol, or methanol were not reported in any of the soil samples analyzed from the CPT or well borings (Table 1) MTBE was reported in samples from borings CPT-2 (at 22 feet bgs), CPT-3 (at 15 and 23 feet bgs), CPT-8 (at 8, 16, and 21 feet bgs), and MW-7 (at 18 feet bgs) MTBE concentrations ranged from 0 0062 to 0 075 milligrams/kilogram (mg/Kg), with the highest concentration reported in the sample from boring CPT-3 at 15 feet bgs Based on these analytical data, the vertical extent of impact to soil appears to be adequately characterized Reported concentrations of TPHG,benzene, and MTBE are summarized on Figure 6 Groundwater Analytical Results TPHG was reported 1n groundwater samples from borings CPT-2 (at 12 feet bgs), CPT-3 (at 12 and 18 feet bgs), and CPT-8 (at 12 feet bgs) Concentrations ranged form 66 to 430 micrograms per liter (µg/L) with the highest concentration in the sample from boring CPT-3 at 18 feet bgs TPHD was reported in the sample from boring CPTH at 75 feet bgs (100 µg/L) The laboratory report noted that this reported concentration included compounds uncharacteristic of common fuels and lubricants, and may include some undifferentiated heavier-end hydrocarbons Toluene was reported in the sample from boring CPT-4 at 10 feet bgs (3 6 pg/L) Tame was reported in the sample from boring CPT-3 at 12 feet bgs (1 3 gg/L) Methanol was reported in the samples from boring CPT-3 at 12 feet bgs (60 µg/L), and boring CPT-6 at 11 feet bgs (64 µg/L) MTBE was reported in samples collected from boring CPT-2 (at 12 feet bgs), boring CPT-3 (at 12, 18, and 30 feet bgs), boring CPT-5 (at I I feet bgs), and boring CPT-8 (at 12, 28, and 38 feet bgs) Concentrations ranged form 12 to 690 µg/L, with the highest concentration reported in the sample from boring CPT-3 at 18 feet bgs Based on these analytical data,the vertical and lateral extent of groundwater impact appears to be adequately characterized TPHG, benzene, and MTBE concentrations for groundwater samples collected during this investigation are presented in Figure 7 P Voe's Truck Plaza\ReportslCPT report 08-2004 doc