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Environmental <br /> Mr.Scott Rickman Resources <br /> 13 June 2007 Management <br /> Page 4 <br /> Based on the analytical results, ERM instructed Entech to analyze <br /> Ladditional samples collected during this investigation for TPH in the <br /> diesel and motor oil ranges to define the extent of impacts to soil. It <br /> should be noted that the additional samples were analyzed just beyond <br /> the holding times for these constituents. The analyses for TPH-d and <br /> TPH-mo were requested 6 days past the 14-day extraction holding time. <br /> Accordingly, the sample data are considered estimated. It is our <br /> professional opinion that the qualified data can be used for decision- <br /> making purposes. The laboratory analyzed the samples collected at 5.5 <br /> feet bgs during drilling activities for TPH-d and TPH-mo from borings <br /> containing detected concentrations at 1 foot bgs. Analytical results <br /> indicated that samples SB-1 and SB-5 collected at 5.5 feet bgs had <br /> detections of TPH-mo at concentrations of 150 and 13 mg/kg, <br /> respectively. Samples analyzed from borings SB-2, SB-4, and SB-6 at a <br /> depth of 5.5 feet bgs all had no detections of TPH-d or TPH-mo at <br /> concentrations above laboratory reporting limits. While no TPH-d or <br /> TPH-mo were detected in SB-4 at 5.5 feet bgs, the laboratory report <br /> indicated a hydrocarbon was detected in the range of C10-C32 at a <br /> concentration of 3 mg/kg. <br /> ERM instructed the laboratory to analyze the sample collected from <br /> boring SB-3 at 15 feet bgs for TPH-d and TPH-mo. The analytical results <br /> indicated no detections of either of these compounds above laboratory <br /> reporting limits. While no TPH-d or TPH-mo were detected in SB-3 at 15 <br /> feet bgs, the laboratory report indicated a hydrocarbon detected in the <br /> C10-C30 range at a concentration of 4 mg/kg for this sample. <br /> DISCUSSION OF RESULTS <br /> Based on the analytical results from this investigation,TPH within the <br /> diesel and motor oil ranges were the only compounds detected in soil <br /> samples analyzed. There are no USEPA Region IX Preliminary <br /> Remediation Goal set for TPH compounds. <br /> The TPH analytical results were compared to the San Francisco Bay <br /> Regional Water Quality Control Board.Environmental Screening Levels <br /> 4. (ESLs). The ESLs were developed by the Regional Water Quality Control <br /> Board to facilitate the preparation of environmental risk assessments at <br /> r sites with soil and groundwater impacts; they are not intended for use as <br /> L cleanup goals. Detected concentrations in soil samples collected at 1 foot <br /> L• <br />