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31 August 2005 AGE-NC Project No 96-0232 Page 17 of 30 concentrations of 1 5 mg/kg TPH-g, 0 081 mg/kg benzene, 0 14 mg/kg toluene, 0 026 mg/kg ethylbenzene and 0 18 mg/kg xylene,xylene was detected from product piping removal sample L2B (4 feet bsg)at a concentration of 0 028 mg/kg, MTBE was detected near the southeast corner of the fuel dispenser area from P31-3 feet at a concentration of 0 012 mg/kg 3 2 SMEAR ZONE MTBE-IMPACT Soil samples collected from within the zone of ground water fluctuation(between 7 and 15 feet bsg) are representative of the smear zone Smear zone MTBE-impacted soil was encountered at 10 feet bsg near the southwest,southeast and northeast corners of the fuel dispenser island area from borings P31, P32, P34 at concentrations as high as 0 72 mg/kg(P31),near the south and southwest sides of the UST pit area at 15 feet bsg from borings P19, P20, P22 at concentrations as high as 0 63 mg/kg (P22) At 10 feet bsg, soil boring P31 (southeast corner of fuel dispenser area) also detected TPH-g at a concentration of 3 2 mg/kg, TPH-d at 2 2 mg/kg, BTEX as high as 0 26 mg/kg and TBA at 0 071 mg/kg i 33 SATURATED ZONE MTBE-IMPACT Soil samples collected at depths greater than 15 feet bsg are representative of the saturated zone Saturated zone MTBE-impacted soil was encountered at a depth of 18 feet bsg from boring MW-19 (Banner Avenue) at a concentration of 0 25 mg/kg, at 20 feet bsg from borings P20, P23, P24,P25 and P26 (northwest, south and east sides of the UST pit area and southwest corner of the fuel dispenser area) at concentrations as high as 0 35 mg/kg (P20), at 30 feet bsg from borings P40A, P41,P43,MW 19(Banner Avenue and northern edge of property boundary)at concentrations as high as 0 15 mg/kg(MW 19), and at 45 feet bsg from boring P40A(northern edge of property boundary) at a concentration of 0 022 mg/kg 3 4 VOLUMETRIC CALCULATIONS Figures 10 through 13 depict selected soil sample locations and the estimated extent of MTBE concentrations adsorbed in soil in cross sectional and plan views, analytical results of soil samples are summarized in Tables 1 and 2 Based on Tables 1 and 2 and Figures 10 through 13, on-site soil borings PI,P6 through P 14,P19,P20 through P26,P30 through P35,P37,P39,P40A,P41,MW-1, MW-4,MW-8 and MW-9 are all located within an adsorbed MTBE-impacted soil plume Utilizing Figures 10 through 13,the mass distribution of MTBE concentrations on the site can be determined by splitting the modeled `elbow'-shaped soil plume into two segments (northern impacted-soil segment and southern impacted-soil segment) The volume of each half can be determined by Advanced GeoEnvironmentai,Inc