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4010 lcal Tcrkxus luc Page 5 <br /> Groundwater Moratonng Report <br /> Project No 989 2 <br /> October 4,2004 <br /> The groundwater samples were obtained utilizing a Waterra®-style foot valve and dedicated <br /> t tubing Extreme care was exercised while collecting samples to prevent agitation of the <br /> water moving in the tubing Water samples were transferred from the tubing into 40-m1 <br /> VOA vials, preserved with hydrochloric acid, while nunimizing sample aeration during <br /> ' transfer of the sample All samples were checked for headspace bubbles, labeled, inserted <br /> into foam holders and placed into a cooled ice chest for transport to the laboratory <br /> ' The sampling technician wore disposable gloves while collecting all samples <br /> A chain of custody document, listing all samples collected and their intended analyses, <br /> ' accompanied the samples from the field to the laboratory, thereby providing a means to track <br /> the movement of the samples and ensure their integrity <br /> ' 2.2 Laboratory Analyses <br /> The groundwater samples collected on July 15, 2004, were delivered to Sherwood Labs <br /> ' Corporation (ELAN 1400), of Hilmar, California, for the following analyses <br /> • Benzene, toluene, ethylbenzene and total xylenes (BTEX)by EPA method 8020/8015 <br /> • Gasoline range petroleum hydrocarbons (TPH-G)by EPA method 8020/8015 <br /> • MtBE by EPA method 8021B (positive results confirmed by EPA method 8260) <br /> ' The detection limits for these compounds are listed in the laboratory data sheets included in <br /> Appendix C and summarized in Table 3 of Appendix A A Chain of Custody was completed <br /> for all samples collected and tracked to ensure sample integrity <br /> ' On September 7, 2004, the laboratory data were submitted electronically to GeoTracker as <br /> required under AB2896 The confirmation number for the electronic submittal is <br /> ' 1632075428 <br /> 2.3 Groundwater Analytical Results <br /> ' • Low concentrations of TPH-G and BTEX constituents were detected in MW-1 and MW- <br /> 4 TPH-G and BTEX constituents were not present in any other monitoring wells above <br /> ' laboratory reporting limits <br /> • Trace concentrations of MtBE were present in MW-1 <br /> ' • Low concentrations of MtBE were present in MW-4, MW-5, MW-6, MW-8 and MW-9 <br /> The levels are consistent with previous monitoring events <br /> • A plot of TPH-G versus groundwater elevation for MW-1 shows that generally the <br /> ' concentrations of TPH-gasoline fluctuate with groundwater elevation and that the overall <br /> concentrations have decreased two orders of magnitude over time <br /> k <br />