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3 November 21, 2011 Cardno ERI 2789C.R02 Former Mobil Service Station 99CAS, Stockton, California (ETIC, 2011). Cumulative groundwater analytical results are included in Tables 1A through 1C. Well construction details are presented on Table 2. Cumulative soil analytical results are included in Tables 3A through 3C. Fueling System Activities Three gasoline USTs, associated product and vent line piping, and a used -oil UST were excavated and removed in September 1994 (ETIC, 2011). The gasoline USTs were located on the Berndt property, and the used -oil UST was located on the Lavagnino property (ETIC, 2011). Concentrations of TPHg and BTEX were reported in soil samples collected during the excavation with concentrations of TPHg reported up to 19,000 mg/kg in the sample collected from 15 feet bgs in the southern area of the second tank. Site Assessment Activities Site assessment activities have included the advancement of borings B1 through B4, CPT1 through CPT5, and CPT6A, and the installation of wells MW1 through MW8, DW1 through DW4, EX1, EX2, VEW1 through VEW4, and V1 through V10 (ETIC, 2011). Maximum hydrocarbon concentrations in soil have been reported in the interval between approximately 20 and 73 feet bgs. Remedial Activities ETIC Engineering, Inc. (ETIC) conducted a six -hour SVE pilot test in August 2009. Wells VEW1A, VEW113, VEW2A, and VEW3 were used as the extraction wells. Wells VEW1B, VEW2A, VEW2B, VEW3, VEW4, MW2, MW4, and MW5 were used as the observation wells. The maximum vacuum level in the extraction wells ranged from 10 to 10.5 inches of mercury. The vapor flow rates in the extraction wells ranged from 8 to 53 scfm. The estimated radius of influence (ROI) was 18 to 59 feet for the shallow -screened wells and 29 to 60 feet for the deep -screened wells. During the test, 15.11 pounds of TPHg and 0.03 pound of benzene were removed (ETIC, 2011). ETIC conducted a slug test using extraction wells EX1 and EX2 in November 2009. The mean hydraulic conductivity during the test was 7.38 x 10-4 centimeters per second (ETIC, 2011). ETIC conducted a DPE pilot test on extraction wells EX1 and EX2 in January 2010. Concentrations of TPHg and BTEX increased during the test. Maximum flow rates of 90 and 93 acfm were observed in wells EX1 and EX2, respectively. The average groundwater extraction rates for wells EX1 and EX2 were 0.89 and 0.91 gpm, respectively. The estimated vapor extraction ROI was 40 to 80 feet for the shallow -screened wells and 40 to 45 feet for the deep -screened wells. The estimated groundwater extraction ROI was 11.4 to 29 feet. During the