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<br /> address ruordtocing of VOC conumina don beneath sad,adjacent to the apartments. Due
<br /> ' to the presence of several VOC plumes,in both soil and groundwater in the immediate
<br /> vicinity of,and beneath the apartments,extraction of soil vapor from each well should be
<br /> managed to eliminate plume migration and enhance VOC seduction from beneath the
<br /> apartment buildings, Plumes of concern include,but are not linaited to the following:
<br /> a. LNAPL present in the DPE area and the non-delineated extension of the
<br /> LNAPL to the west of Well MW-21 and DPE-8,in the direction of,and probably
<br /> beneath the apartments';
<br /> l b. VOCs present is soil in the L&M OU portion of Pareel 2A,including soils not
<br /> j excavated and soils present beneath the liner placed at approximately 10 feet bgs;
<br /> e. The gasoline plume present in the vicinity of Well MW-46 as a result of a 20,000
<br /> to 40,000 gallon underground gasoline spill that extended from the L&IVI facility
<br /> into a basement of a house located across(immediate south oo Main Street=;
<br /> d. The gasoline plume present to the immediate north of,and beneath Weber in the
<br /> vicinity of Well MW-40i and along the L&M pipelines,that resulted£torn a
<br /> pipeline break of approximately 50,000 gallons oEethyl gasoline while attempting
<br /> to pump from the Tuleburg Levee to the Uhl OU,resulting in minor surface
<br /> releases and with"...most of 50,000 gallons lost underground..."'
<br /> C. The gasoline/diesel plume extending from the northern portion of the L&M OU
<br /> toward Well MW-43'.
<br /> 8. Several volatile contaminants have been identified in soil`associated with,and
<br /> groundwater'from,WcUMW-46. The presence of these contaminants requires an
<br /> assessment of the need for installing hotizo W wells beneath the aparrment buildings
<br /> located to the immediate south and southwest of WellMW-46.
<br /> 9. SVE vapor data should include sampling on a weekly basis for the fust month and
<br /> monthly thereafter. Modifications to the list of analytes and sampling frequency should
<br /> be evaluated on a seati-annual basis.
<br /> 10. As stated in the Work Plan,the vapor atialyscs reporting wO include BT&X and fuel
<br /> oxygenates. Since the Method TO-15 results in analysis of an EPA Method 8260
<br /> equivalent,reporting should include all analytes and not just selective BT,%and fuel
<br /> oxygenates.
<br /> t In June 2004,the Mackness of LNAPL in Wcll INW-21 was 0.03 feet,Well OPE-$was 0,64 feet and a sheca in
<br /> DIRE-9(Sacor 2005,2W4 Annual and Fourth Quarter 204¢Sit@ Statas aad Groundwater ldonitodng Repot;Table
<br /> 3). The closest monitoiing wells to the weir of WeU 4%IW 21 include y11V 23/MW 24 loaeted appcox;matcly 300 feet
<br /> to the carat,Welt MW-221mved 4ppmximately 150 feet to thesouib,sod Wells tiIW-d4A%M-45 located
<br /> approxi muiy 400 feet to the east-southeast.
<br /> 2 The presence of elevated eombusdble gas in Well MW-31,located approxitu r*100 feet south-southwest Qf&fW
<br /> 46,subsruuiates the presence of contbusdble gas beneath the npatuaent builtTmgs located to the south of Well MV.
<br /> 46,aids resulting&oat a 20,000 to 40,000 galloon gasoline spill tbat went from the LAM site,across Main Street and
<br /> into a house baseraear,thio occuringin the 1946 to 1948 time period.
<br /> 2 Ile thickness of LNAPL[o Wel MW-40 vns 058 feu on 3 June 2004 and soil campling performed during well
<br /> installation on 17 Maly 2004 indicated a TPH signature of*gasoline dominated release,
<br /> i McKinnon deposition,pg,143.
<br /> S The thickness of LNAPL In Well MW-43 wis 2,17 feet on 3 June 2004 and soil sampling performed dudag wen
<br /> lostak oa on 17 May 2004 indicated a TPH sigaawre of a mixed gasoline/diesel dominated releases
<br /> 4 The soil sample collected from 26 feet bgs eoaWned ITHg at 79 nig/kg,7P14d at 110 mg/kg,bent me at 41
<br /> ug/kg,and several x-benzcaes.
<br /> I Grounchvater sampling identified the pseswre of TPHg ar 6.600 ug/L,TPHo at 99 ug/I,benzene at 760 ug/L,
<br /> aaphdWcae st 160 ug/L;and several s-beatenes,toluene,ethylbenzwe,xylene,7Br1,1-methyluphzlme and 2-
<br /> methyinaph2leae
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<br /> Las Astoes,Nevada Gly%ad S7n Diego Golden Stat.--Enviaoamm-ed
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