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1 i <br /> i} <br /> 1 <br /> To further define groundwater quality beneath the site, a second round of groundwater sampling <br /> was conducted on lune 21, 1991. Nondetectable levels of petroleum constituents were recorded <br /> in monitoring wells MWl and MW3 Monitoring well MW2 contained only detectable levels <br /> I <br /> of TPHD, 68 µg11. No constituents were present above Maximum Contaminant Levels <br /> established by the State Department of Health Services. <br /> I A final round of sampling was completed on August 22, 1991. Only monitoring, wells MW 1 <br /> and MW2 contained benzene above method detection limits, 0.41 and 0.63 µg11, respectively. <br /> No constituents were present above Maximum Contaminant Levels established by the State <br /> Department of Health Services A summary of the laboratory analyses is presented in Table 4 <br /> and laboratory reports with chain-of-custody documents are presented in Appen&v IV. <br /> Table 4. Chevron Stockton Laboratory Analysis of Groundwater - May, June, and August <br /> 1991. Results presented in µg11 (ppb). <br /> 17DATE SAMPLE BENZENE TOLUENE : ETHYL XYLENES TPHf} TPHD <br /> I ID BENZENE (Il ) <br /> 517191 MWl 085 15 10 29 41 , ND <br /> MW2 077 ND ND 036 31 84 <br /> MW3 ND ND ND ND NDi ND <br /> 6121191 MWl ND ND ND ND NDi ND <br /> ( MW2 ND ND ND ND ND' 68 <br /> MW3 ND ND ND ND NDS ND <br /> 8!22191 MW 1 041 ND ND ND ND ND <br /> MW2 063 ND ND ND ND ND <br /> MW3 ND ND ND ND NDi ND <br /> Detection Limns 030 030 030 1 030 301 50 <br /> Notes <br /> BTEX = Analysis by EPA method 8015/8020 <br /> L TPHG = Total Petroleum Hydrocarbons as Gasoline <br /> TPHD = Total Petroleum Hydrocarbons as Diesel <br /> (1) = Analysis by Modified EPA method 8015 <br /> I (2) = Analysis by Modified EPA method 8015 <br /> . ND = Compounds Not Detected above Method Detection Limits <br /> r <br /> } <br /> m„"=u.s.e.rw .M7 7 <br /> csaa�l <br /> I <br /> L <br />