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Fill material was encountered in boing HP-2 to a depth of approximately 15 feet bgs. A very stiff, <br /> elastic silt was encountered in this boring from approximately 15 feet bgs to 23 feet bgs. Below this <br /> was a silty sand to 25.5 feet, the maximum depth sampled. No field evidence of hydrocarbon impact <br /> (odor or discoloration) was observed in soil samples collected from either boring. <br /> Based on the lithologies observed during the investigation and previous work at the site, it appears that <br /> a stiff elastic silt is laterally continuous beneath the site from approximately 15 to 25+/- feet bgs. <br /> Groundwater was not encountered in boring HP-1. Groundwater was encountered in a silty sand at a <br /> depth of approximately 25 feet bgs during drilling in boring HP-2. <br /> ANALYTICAL RESULTS AND CONCLUSIONS <br /> Concentrations of TPHg, BTEX, TPHd, TPHk, and heavy hydrocarbons were not detected in the <br /> groundwater sample collected from below the former lube oil UST. This indicates that the trace levels <br /> of toluene, ethylbenzene and xylenes detected in the excavation soil sample have not impacted <br /> groundwater. The lack of any indication of residual soil contamination suggests biological activity has <br /> degraded any residue that may have remained in the soil following excavation. No threat to <br /> groundwater exists. No evidence of soil contamination was observed in boring HP-1, confirming the <br /> clean excavation of the former used oil UST located adjacent to the loading dock. Although a <br /> groundwater sample could not be collected at this location, soil type would tend to adsorb any <br /> contaminant that might have existed and would provide a suitable substrate for biological activity. <br /> Based on the results of this investigation and previous analyses Ground Zero concludes that no residual <br /> soil contamination exists and that groundwater has not been impacted. No further action is <br /> recommended and we request case closure at this time. <br /> Please call with any questions regarding this report. <br /> Sincerely, <br /> Ground Zero Analysis, Inc. <br /> rJet <br /> EocFPowernager GREGORY P. <br /> STAHL <br /> No. 5023 <br /> Gregory P. Stahl �lgTF Uf CAUF���\P <br /> CA Registered Geologist No. 5023 <br /> cc: Elizabeth Thayer, CRWQCB <br /> Pat Riddle, Riddle & Isola <br /> Norm Crum, Woolsey Oil <br />