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i ) Chevron Products Company 2 rChevron Serv�ce_Stahon 9-4275 _ _ July'M 2002 DISCUSSION: On June 6 and 7,2002,SECOR conducted groundwater monitoring and sampling for the 2nd quarter 2002 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 summarize groundwater elevations and dissolved concentrations at Arco station No 2133 for the second quarter 2002 Water level elevations are summarized in Figure 2 2nd quarter groundwater gradient flowed approximately north at 0 004 ft/ft and northwest at 0 007 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- butanoVtertiary-butyl-alcohol(TBA), 1,2 dichloroethane(1,2 DCA)and 1,2 dibromoethane(EDB) DIPE,ETBE, toluene 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 150 micrograms per liter(µglL)(MW-6)to 1,700µg/L(MW-2) MtBE was detected in samples from seven wells at concentrations ranging from 0 5 gg/L(MW-8)to 1,700 gg/L (MW-1) Benzene was detected in one well at a concentration of 5 0µglL (MW-2) Ethylbenzene was detected in samples from two wells at concentrations of 1 0µg/t(MW-1)and 3 0µg/l(MW-2) Xylene was detected in samples from two wells at concentrations of 10µg11 (MW-1) and 4 0µg11(MW-2) TAME was detected in samples collected from four wells at concentrations of 0 5 µg/L(MW-9)to 15 0µg/L(MW-1) 1,2 DCA was detected in samples collected from three wells at concentrations ranging from 0 5 gg/l(MW-2) to 2 0 gg/L(MW- 6) TBA was detected in one well at a concentration of 34 gg/L(MW-1) Groundwater concentrations are summarized for TPHg,Benzene and MtBE in Figure 3 Groundwater analytical data is summarized in Tables 1 and 2 ATTACHMENTS: • Table 1 —Historical Groundwater Elevation and Analytical Data O Table 2—Groundwater Analytical Results—Oxygenate Compounds o Figure 1 —Site Location Map ® Figure 2—Groundwater Elevation Contour Map,June 6,2002 a Figure 3—Groundwater Concentration Map,June 7,2002 0 Attachment A-Field and Laboratory Procedures • Attachment B -Field Data Sheets • 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 11Chevron1942751Penodic Monitonng\Q M R12QMR02 doc