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<br /> ! LEARWATER
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<br /> • Separ`ate-phase petroleum was rirot detected in any of the monitoring wells ' I
<br /> • TPHg was detected in groundwater samples collected' from monitorin wells
<br /> MW-1, and MW-2 in concentrations of'87 parts per billion (ppb),I an 7 0001 ;
<br /> respectively I Benzene was detected in groundwater, samples collected ,from '
<br /> R
<br /> monitoring wells MW-1, MW-2, MW-3, MW-4 and MW-5 in concentrations'of 89 ' I
<br /> PP 340PPb 98'ppb, 5 5 PPb and 140 ppb;res ectivelY
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<br /> 5.0 CONCLUSIONS AND RECOMMENDATIONS
<br /> I rr
<br /> I '
<br /> Results of recently completed ' and 'histo,,}}c field activities !indicate that, the'
<br /> distribution of hydrocarbons in the ,soil`'has 'been' defined, and the extent of 1
<br /> groundwater impact, while not delineated in the downgradient'direction, appears to
<br /> be'predominantly'concentrated in the immediate vicinity! of the former UST's and '
<br /> piping , In order tot complete the site characterization and provide data 'required for '
<br /> Y the determination 'of the appropriate remedial approach, the following project task
<br /> elements are recommended It I II Ir ' I 1 ,
<br /> ,
<br /> ` • Complete'therDecember, 1994 sampling event in order to confirm hydrocarbon
<br /> f concentrations in newinstalled wells
<br /> ti
<br /> If elevated concentrations of hydrocarbons continue!to be detected' in MW 5,
<br /> install a single additional, nonitoring wells across Yosemite,street, as` shoi'vn iii,, 21
<br /> r Figure 5
<br /> r
<br /> e , ' 1 ' '
<br /> • ° Install two air lsparging ,wells and soil vapory extraction well's in the 'locations
<br /> shown on Figure 5 Well' installation methods'would be consistent I with those
<br /> followed during, the most- recent phase `of' investigation` (refer to',protocols in
<br /> ` I IClearwater's"June, 1994 Workplan) ' Proposed well construction detail is'shown
<br /> 1 r
<br /> on Figure,6
<br /> {, 1 { „
<br /> Conduct' a day,long soil vapor extraction/air rlspargingl pilot test in accordance 1 ! 4,
<br /> 1 �r , ,r 'Appendix
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<br /> ,
<br /> with L,the' "pro'tocols incl'ude'd'{ in ''Appendix F , 'Reports results imta Problem,,!
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<br /> EAssessrrient/Conceptual;Remedial'Appr'oach'`Report If l i
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