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1 rwologia I7i"hnusInc Page 2 <br /> Groundwater Mon tormg Report <br /> Project No 989 2 <br /> March 29,2004 <br /> I <br /> concentrations of MtBE fluctuate with groundwater elevation and that the overall MtBE <br /> concentration has decreased over time (Chart 2) <br /> 1 <br /> 10 GROUNDWATER MONITORING <br /> 1.1 Groundwater Sam lin <br /> P g <br /> ' On February 12, 2004, Del-Tech Geotechnical. Support Service personnel arrived on-site, <br /> opened the wells and measured the depth to water with an electrically actuated sounding <br /> tape The water level reading was recorded to an accuracy of 0 01 foot If free-floating <br /> ' product had been suspected, a clear disposable bailer would have been used to gauge the <br /> interface No floating product was observed during this sampling event <br /> Stagnant water in the well casing was purged using a Waterra© pump (MW-1 through MW- <br /> S and MW-101) and a centrifugal pump (MW-7 through MW-9) with dedicated tubing The <br /> rate of well purging was monitored The wells were purged of at least three casing volumes <br /> and until the groundwater parameters (temperature, conductivity and pH) had stabilized <br /> (Appendix B) indicating that water representative of actual aquifer conditions was entering <br /> the well Groundwater parameter stabilization was characterized by three successive <br /> readings within 10% <br /> All water removed from the monitoring well and not used as a sample was placed into a 55- <br /> gallon DOT approved container that was properly labeled and temporarily stored on-site <br /> I <br /> ' The groundwater samples were obtained utilizing a Waterra foot valve and dedicated <br /> 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 minimizing 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 /> I <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 <br /> track the movement of the samples and ensure their integrity <br />