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Chevron Products Company 2 Chevron Service Station 9-4275 Ani 26 2002 • DISCUSSION: On March 11,2002,SECOR conducted groundwater monitoring and sampling for the I"quarter 2002 at the Arco station No 2133 (2908 West Benjamin Holt Drive) and Chevron station 9-4275 Nine Chevron wells were sampled during this event Arco wells were also sampled but this data is not included in this report,However Figures 2 and 3 summarizes groundwater elevations and dissolved concentrations at the Arco station No 2133 for the first quarter 2002 Water level elevations measured during this monitoring event are summarized in Figure 2 During the 4th quarter,the calculated groundwater gradient flowed to the north at 0 004 ft/ft and to the northwest at 0 002 ft/ft This gradient is consistent with historical data Groundwater samples were analyzed for total petroleum hydrocarbons quantified as gasoline(TPHg),benzene, toluene,ethylbenzene,and xylenes (BTEX), and the fuel oxygenates including methyl-tertiary-butyl-ether(MtBE), ethyl-tertiary-butyl-ether(EtBE),di-isopropyl ether(DIPE),tertiary-amyl-methyl-ether(TAME),tertiary- butanol/tertiary-butyl-alcohol (TBA), 1,2 dichloroethane(1,2 DCA)and 1,2 dibromoethane(EDB) DIPE,ETBE, TBA and EDB were not detected in samples from any of the wells TPHg was detected in samples collected from four wells at concentrations ranging from 96 micrograms per liter(}tg1L.) (MW-1) to 2,600 pg/L (MW-2) MtBE was detected in samples from seven wells at concentrations ranging from 0 6 µg/L(MW-5) to 2,2001tg/L(MW-1) Ethylbenzene was detected in samples from three wells at concentrations of 0 6µg/t (MW-1 and MW-3) to 11 0 µg11(MW-2) Xylene was detected in samples from two wells at concentrations of 0 6 µg/l (MW-1) and 7 0µg11 (MW-2) TAME was detected in samples collected from four wells at concentrations of 0 6 uglL(MW-9)to 22 0 µg/L(MW-3) 1,2 DCA was detected in samples collected from two wells at a concentration of 2µg/l (MW-6 and MW-9) Groundwater concentrations are summarized for TPHg,Benzene and MtBE in Figure 3 Groundwater analytical data is summarized in Table 1 and Table 2 ATTACHMENTS: • Table 1 —Historical Groundwater Elevation and Analytical Data 0 Table 2—Groundwater Analytical Results—Oxygenate Compounds o Figure 1 —Site Location Map o Figure 2—Groundwater Elevation Contour Map,March 11,2002 o Figure 3—Groundwater Concentration Map,March 11 and 12,2002 o Attachment A-Field and Laboratory Procedures ® Attachment B -Field Data Sheets e Attachment C-Certified Laboratory Analytical Reports and Cham-of-Custody Documentation cc Marty Hartzell,RWQCB-CVR,Sacramento,CA Bob Cochran,Chevron Products Company, San Ramon,CA I\Chevron1942751Penodic MonitonnglQ M RUQMR02 doc