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Geofagua!?echnrrs Inc Page 3 <br /> Groundwater Monitoring Report <br /> Project No 723 2 <br /> June 29,2000 <br />' The dedicated Waterra pump was used to collect each sample <br /> Extreme care was exercised while transferring the sample into 40-m1 VOA vials preserved <br /> with hydrochloric acid All samples were checked for headspace bubbles, labeled, inserted <br /> into foam holders and placed in an ice chest cooled to 4°C for transport to the laboratory <br /> The sampling technician while collecting all samples wore disposable gloves <br /> A chain of custody document, listing all samples collected and their intended analyses, <br /> accompanied the samples from field to the laboratory, thereby providing a means to track <br /> their movement and ensure their integrity <br /> 1 1.3 Laboratory Analyses <br /> ses <br /> The groundwater samples collected on May 4, 2000 were delivered to Sherwood Labs of <br /> Hilmar, California(certification#1400) for analysis of <br /> • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX)by method EPA method 602 <br /> • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) <br /> • Fuel Oxygenates (MTBE, DIPE, ETBE, TAME & TBA) by EPA method 8260B <br /> The detection limits for the above analyses are listed in Table 2 of Appendix A while the lab <br /> analytical results are presented in Appendix B <br /> 2.0 FINDINGS AND DISCUSSION <br /> The results of the groundwater sample analysis show the following <br /> • BTEX and TPH-G concentrations continued to increase in wells MW-2, MW-3 and MW- <br /> 1 <br /> • Wells MW-4 & MW-101 exhibited decreases in contaminant concentration since the <br /> December 1999 monitoring event <br /> • The contaminant concentrations in well MW-6 continue to fluctuate <br /> • MW-101 showed low levels of BTEX and TPH-G for the third consecutive event This <br />' well was installed in August 1999 through the upper, heavily contaminated zone of soil <br /> and groundwater GTI has observed that these wells will typically test positive for <br /> contaminants due to contaminated soil and groundwater being dragged down the borehole <br /> 1 during drilling This drilling artifact usually dissipates within a few months of the <br /> drilling and any contamination that is present long term is a portion of the larger <br /> groundwater plume GTI recommends continued quarterly monitoring to see if the levels <br />' decrease before further deep investigation is continued <br /> • <br /> I <br /> 1 <br />