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%Noe *.d <br /> 880 VICTOR, LODI <br /> PAGE <br /> • According to borehole logs, lithology at the site from surface to approximately 60 <br /> feet bsg is composed of silt lifts with alternating sandy lifts and silty-sand lifts. Silt <br /> was encountered from approximately 56 feet to 61 feet bsg in SB-4, but flowing <br /> sand was encountered beneath a silt lift in SB-3 at approximately 60 feet bsg. <br /> Lithology has not been characterized below 60 feet bsg. <br /> PHS/EHD disagrees with the conclusion of Cambria's Site Investigation Report that <br /> MTBE has not migrated vertically a significant distance into saturated soils. The area <br /> of the contaminated soil which would identify the source of the high concentrations of <br /> TPH-g, BTEX, and MTBE detected in groundwater has not been identified. <br /> Analytical results of the soil samples collected from beneath the UST at various depths <br /> in 1994 and 1996 were relatively low in detectable petroleum hydrocarbon <br /> constituents. The release area of the UST system has not been identified. The area of <br /> the release should first be located so the vertical extent of the contamination plume can <br /> be defined in this source area. <br /> PHS/EHD recommends investigating the entire system at the site, including the <br /> product line and dispenser areas, to locate the source area of the soil and groundwater <br /> contamination. Soil samples beneath both existing UST should be obtained for <br /> laboratory analyses. PHS/EHD recommends characterizing the lithology of the site <br /> from below 60 feet bsg using Cone Penetration Technology or continuous core <br /> technology. Discrete grab water samples should be collected for laboratory analyses to <br /> identify the vertical extent of MTBE and petroleum hydrocarbon contamination in the <br /> groundwater. Submit a work plan to PHS/EHD by September 1, 1999. <br /> If you have any questions, please feel free to contact Jeffrey Wong at (209) 468-0335. <br /> Donna Heran, REHS, Director <br /> Environmental Health Division <br /> Jeffrey Wong, REHS Margaret Lagorio, REHS <br /> LOP/Site Mitigation Unit IV Supervisor <br /> C: CRWQCB, Central Valley Region -Mark List <br /> C: Cambria Environmental Technologies, Inc. -Joe Neely <br />