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1 <br /> Mr Travis Bryant Project 792759 <br /> March 23, 2000 <br /> Page 2 <br />' gasoline The groundwater plume has not been delineated, but it extends downgradient <br /> (eastward) as far as Van Buren Street <br /> On February 25, 1997, an EMCON geologist observed V&W Drilling, Inc , of Rio Vista, <br /> California, drill three vertical soil borings (B-1, B-2, and B-3) Soil boring B-1 was <br /> converted to vapor extraction well VW-1, and borings B-2 and B-3 were converted to <br />' groundwater monitoring wells MW-1 and MW-2, respectively Residual hydrocarbons <br /> were detected in soil samples collected from borings B-1 through B-3 The highest <br /> concentrations were detected in soil boring B-1, drilled beneath the former UST Residual <br />' petroleum hydrocarbons were not detected in the vadose zone (0 to 215 feet below <br /> ground surface) soil borings B-2 and B-3, but were detected in the saturated zone <br /> Analytical results of groundwater indicated dissolved hydrocarbons were detected in <br />' monitoring wells MW-1 and MW-2 (EMCON, August 4, 1997) TPHG was detected in <br /> monitoring wells MW-1 and MW-2 at concentrations of 18,000 parts per billion (ppb) <br /> and 220 ppb, respectively Benzene was detected in monitonng wells MW-1 and MW-2 <br />' at concentrations of 4,400 and 33 ppb, respectively <br /> GROUNDWATER MONITORING: FIRST QUARTER 2000 <br /> On February 25, 2000, an IT technician was on site to measure depths to groundwater and <br /> 1 collect groundwater samples from wells MW-1 and MW-2 for subjective and laboratory <br /> analyses Floating product was not observed in groundwater monitoring wells (see Table 1) <br /> IT's sampling and analysis procedures are presented in Appendix A. <br />' At the time of the monitoring event, groundwater levels were 19 32 and 19 44 feet below <br /> ground surface in wells MW-1 and MW-2, respectively These levels are approximately <br />' 0 91 foot higher than the November 1999 monitonng event levels <br /> Groundwater samples were collected from monitoring wells MW-1 and MW-2 and were <br />' analyzed at Sequoia Analytical in Sacramento, California The groundwater samples were <br /> analyzed for total petroleum hydrocarbons as gasoline (TPHG) DHS/LUFT, for benzene, <br /> toluene, ethylbenzene, and total xylenes (BTEX), and methyl tertiary butyl ether (MTBE) <br />' using USEPA Method 8020 Copies of the chain-of-custody records and laboratory <br /> analysis reports are presented in Appendix B <br />' Total xylenes were detected in well MW-1 at a concentration of 2 98 micrograms per liter <br /> (µg/L) and TPHG was detected in well MW-2 at a concentration of 516 gg/L All other <br />' constituents were below laboratory detection limits Results of laboratory analyses are <br /> presented in Tables 1 and 2 <br /> F <br /> CP1N ICamPklDatalArchiveliBC\IBC-5tkn\Qtrly\SIKNQ100 doe-98Usg i IT Corporation <br /> Rev March 23,2000 <br /> I <br />