SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Complaint No. 11917 - 3 - • 8 November 2013 Valero/Jamar Service Station Stockton, San Joaquin County 260 ug/L in March 2011. Groundwater concentrations show a reduction since start-up of the soil vapor extraction (SVE) system, indicating that the cleanup system is operating effectively. The groundwater data do not indicate the MTBE plume has migrated 135' to the north-northwest in the direction of your residence at 931 South Oro Avenue. The consultant for the Jamar site estimates the extent of petroleum impacts in groundwater are limited to about 40' to the north-northwest of MW-12A. Soil impacts at the Jamar Site are defined to north of the USTs by samples collected at borings B1 and MW12A and to the northeast of the USTs by samples collected at boring MW2. B1 and MW-12A soil results are iven in milli rams per kilo ram. Sample Depth TPHg Benzene I Toluene Ethylbenzene Xylenes MTBE B1-25 25' <1.0 <0.005 <0.005 <0.005 <0.005 0.81 B1-30 30' 1.3 0.023 <0.005 <0.005 0.14 3.7 B1-35 35' 17 3.7 1.3 0.11 0.34 5.4 B1-40 40' 50 2.8 4.2 0.88 4.5 3.5 B1-45 45' 4.2 0.24 0.52 0.099 0.61 1.5 B1-50 50' 380 3.2 15 5.7 33 1.3 B1-55 55' 11 1.1 2.1 0.22 1.2 0.27 MW12A-50.5-51' 51' 6.2 0.33 0.65 0.29 1.0 <0.010 M W 12A-55.5-56' 56' 1,100 .1.2 21 27 120 <0.80 MW12A-60.5-61' 61' <1.0 <0.005 0.006 <0.005 0.012 0.0019 MW2-30 30' <1.0 <0.005 <0.005 <0.005 <0.005 <0.005 MW2-35 35' 1.5 0.21 0.049 0.009 0.13 <0.005 MW240 40' 1.2 0.079 0.034 <0.005 0.017 <0.005 MW2-45 . 45' 1.6 0.33 0.078 0.043 0.082 0.0075 MW2-50 50' 4.3 0.14 0.2 0.053 0.21 <0.005 MW2-55 55' 4.7 0.029 0.81 0.17 0.75 0.012 MW2-60 60' 4.7 0.73 0.69 0.15 0.75 0.025 MW2-65 65' 3.8 0.63 0.035 0.03 0.16 0.053 MW2-70 70' 1.5 0.7 0.023 <0.005 0.11 0.0056 MW2-74 74' 5.5 2.2 0.033 <0.005 0.088 <0.005 TPHg=total petroleum hydrocarbons as gasoline MTBE=methyl tert butyl ether 1,2-DCA=1,2-dichloroethane NA=not analyzed Waste oil and kerosene USTs removal confirmation soil results are given in milli rams per kilo ram. Sam le Depth TPHd Benzene Toluene Eth (benzene X lenes Waste Oil 8' 20 <0.005 0.006 <0.005 0.022 Kerosene 8' 32 <0.005 <0.005 <0.005 0.015 TPHd=TPH as diesel,which was footnoted as motor oil in the waste oil confirmation sample result. Kerosene is often reported as TPHd The soil data do not indicate significant shallow soil contamination towards your property. As explained in the letter we sent with these results on 18 September 2013, given the groundwater monitoring data collected from the Jamar Service station that show decreasing levels of petroleum hydrocarbons in the direction of your resident and since the analysis of samples collect from your residence did not contain gasoline, diesel or MTBE, we do not believe the discoloration you observed in the toilet tank is from the neighboring service station. Excelchem detected oil and grease, bromodichloromethane, and chloroform in both samples collected from your residence. Exelchem stated the acetone detected in the analyses was a common lab contaminant, since acetone is used to clean