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�? ' >'XSEM',8Y,EEh{GON 7-18-9fi � 2, ,32PM , ' ENCON SACRAME�tI'0=� N M i -4/14'-Trois <br /> V <br /> F <br /> Mr Lawreisi�e``H.Beasley P l6j D6 P96-070,25, <br /> J4ly¢18, 1996 <br /> fat <br /> ` -300�unplci will be voliected at S-fnot interval,and will be classified using vises dnd manual �� a <br /> � 'M methods according to-the Unified Soil Clatsification SyCLerri`,Sod sarnpics wi31 bei subrrotted n, - j,°i.e <br /> ziF T {- L L <br /> a'.' aLe=ocrtif pd anRlytiG l labr t itory a[><1 VYIu be analyzed for CotaI pi�rokaun lidrocait rro'as r <br /> gasoline,{f'PHG� and *r benrnr, tolucrwy ethylbenzene, and total xyknes EHTFW using <br /> USEPA Methods 8015 mW 81720, respectively (three Soil samples fiom each boring`w�[ be <br /> analyzed). In addition, soil samples collected of diffmnt stratigWa w units (EMCON is r <br /> estimating three (3)differwt units) will be analyzed for permeability,moisture, saturation, <br /> bulk density,and total organic carbon <br /> 1 f � <br /> All generated drill cuttings and excess soil samples wdl be stored ori site and placed on and <br /> covered with visgueen. Four soil sainples will be coll_ccwd from the sol! cuttings and <br /> cornposit�Cd in a state-certified laboratory to dewznunc the appropriate disposal methal <br /> The composited soil sample will be analyzed for TPHG, BTEX, total lead, reactivity, <br /> corrosivity, and ignitabilty. Costs for dispohal of soil and groundwater are not included in <br /> this proposal and will remain the responsibility of Apache. <br /> Task 3•Risk-Based CorMctive Action Evaluation <br /> Subtask 3A-Preparation cif Tier 1 <br /> The Tier l assessment includes comparison of maxiiniiin detected chemical concentrations <br /> in soil with conservative, Health risk-based screening values EMCON has several sources <br /> available for these screening values; it is most likely that the uitarnaily-developed <br /> TRIGGERS program would he used for the Tier 1 assessment, This program_contains a <br /> variety of health nsk-based screening values for petroleum-related compounds, including <br /> USEPA Regidn 9 preliminary remediation goals (DRGs). Maximum duetted chemical <br /> concentrations in groundwater would be compared against nmimuin contaminant levels <br /> (MCLs); in their absence USEPA Region 9 PRGa would be used as "Diggers." A table <br /> sunmiarizing the maximum detected concentrations,"trigger' levels used, and results will <br /> be prepared identifying chemicals detected at concentrations above die conservative <br /> "trigger"levels <br /> i Subtask 3B -Preparation of Tier 2 <br /> In Tier 2. EMCON will produce an RBCA evaluation that will be thorough and sctient>fr-all <br /> Y <br /> dehnsibk,will satisfy agency requirements,and can be used as a definitive kracis for ascertaining <br /> the extent of cleanup at the site,if necesmy The evaluation will conform to a Tier 2 evaluation <br /> as presented in ASTM's ES-38. 1n a=rdance with principal regulatory guidanr.e documents, <br /> the following sui>-tasks are anugmted. <br /> 5At1iVVRCTP96W91 MO2,S AS-9660 <br /> 1 �Y <br /> F <br />