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M. Scott Mansholt <br /> ChevronTexaco -3 - • <br /> Former Lyoth Loading Station 6 July 2005 <br /> Each boring was continuously cored to <br /> field screened for the presence co e maximum depth of a <br /> PID instrument readings organic vapors usin a PProximately 28 feet. The soil core was <br /> g and/or visual observations of is paoted soil thereforetiozi ctos <br /> boring above the water table (15 feet (PID). There were no <br /> submitted for analysis. ) and one below the water table (25 feet) was collected <br /> a each <br /> BTEX and TPH as crude oil (TPHc) compounds were not detected in the soil samples.concentrations of PAHs - <br /> kilogram m Phenanthrene and pyrene,ranging from 0.001 to 0.000Low <br /> detected at theirre st or slightly above the MDLs were reported; results for the remaining p <br /> P MDLs. milligrams per <br /> g ARS were not <br /> According to previous investigations and the recent offsite results, the extent of impacted <br /> has not been adequately delineated north-northeast(downgradient) of the site. Additional offsite <br /> fieldwork is needed. P groundwater <br /> Based on our review, we have the following comments: <br /> • Future soil and/or groundwater samples collected offsite should be submitted for <br /> fingerprint analysis to determine if the impacts are the result of leaks from the OVP or <br /> possibly from other nearby sources. <br /> • Additional soil borings and groundwater sampling should be continued to the northeast <br /> beyond existing data points until the extent of impacts is adequately defined. Step-out <br /> borings should be completed and groundwater sampling conducted util <br /> turnaround time for lab testing. izing a rapid <br /> We concur that additional characterization needs to be completed to adequately delineate the extent of <br /> impacted groundwater downgradient of the site provided our comments above are addressed. <br /> Please notify Regional Board staff at least 48 hours prior to commencing the drilling activities. If you <br /> have any questions or comments,please contact Dean Hubbard at (559) 445-5179. <br /> S2&_ �. (�� Ot <br /> SHELTON R GRAY C. DEAN HUBBARD <br /> Senior Engineering Geologist Engineering Geologist <br /> RG No. 6357 <br /> cc: Michael J. hifuma, San Joaquin County EHD, Stockton <br /> Ronald Hoffman, Tracy <br /> Jeffory J. Scharff, Sacramento <br /> Luis Mercado, SAIC, Sacramento <br />