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7hN3dweII8RO110 <br /> • <br /> No TPH-g, TPH-mo, SVOCs, or VOCs (other than BTEX compounds)have been detected in <br /> groundwater during the Treadwell &Rollo investigations. No significant concentrations of any <br /> metals have been detected in groundwater. <br /> During the 1996 investigation TPH-d was detected at concentrations ranging from below <br /> laboratory reporting limits to 0.47 mg/l, and two samples contained BTEX compounds up to <br /> 0.004 mg/1. During the 1999 investigation no petroleum hydrocarbons were detected except for <br /> 0.0012 mg/l of total xylenes in well MW-2-10. During the recent investigation no BTEX <br /> compounds were detected, and TPH-d was detected at concentrations ranging from below <br /> laboratory reporting limits to 0.18 mg/1. The laboratory has stated that the detections do not <br /> appear to match a diesel standard, and also that"paint contamination" occurred in the laboratory <br /> and effected the results of some sample batches during the time these samples were being <br /> processed. The paint contamination, which was caused by spray painting in the laboratory, was <br /> identified on chromatograms as two distinct peaks in the diesel range. While the TPH-d detected <br /> • in groundwater shows elevated peaks in the same ranges as the paint contamination <br /> chromatogram,the laboratory said that they still have to quantify this detection as diesel. A copy <br /> of the 26 June 2000 memorandum from Curtis & Tompkins Laboratory discussing this issue is in <br /> Appendix D, and includes a copy of the paint contamination chromatogram. <br /> 4.1.2 Area 11 <br /> The studies indicate that soil at Area 11 has been minimally impacted by petroleum fuel <br /> hydrocarbons and lead. Treadwell &Rollo has collected 19 soil samples for lead analyses of <br /> which 1 sample exceeded 1,000 mg/kg (the PRG for industrial sites) and 1 other sample <br /> exceeded 400 mg/kg (the PRG for residential sites). Both of these samples were collected at 1 <br /> foot deep, and deeper samples do not appear to have significant lead concentrations. <br /> Petroleum hydrocarbons have been detected in 33 of the 49 samples analyzed at Area 11. Two <br /> of these samples had concentrations greater than 1,000 mg/kg, and all other detections had <br /> • <br /> 27 <br /> 25970309.DGD 24 August 2000 <br />