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40061#01 Technics W. Page 2 Groundwater Monitoring Report Project No. 989.2 April 30,2003 ' fluctuate with groundwater elevation and that the groundwater elevation and MTBE concentration has decreased over time (Chart: MW-6). 1.0 GROUNDWATER MONITORING ' 1.1 Groundwater Sampling A g ' On February 14, 2003, Del-Tech Geotechnical Support Service personnel arrived on-site, opened the wells and measured the depth to water with an electrically actuated sounding ' tape. The water level reading was recorded to an accuracy of 0.01 foot. If free-floating product had been suspected, a clear disposable bailer would have been used to gauge the interface. No floating product was observed during this sampling event. Stagnant water in the well casing was purged using a Waterra pump with dedicated tubing. The rate of well purging was monitored. The wells were purged of at least three casing ' volumes and until the groundwater parameters (temperature, conductivity and pH) had stabilized (Appendix B) indicating that water representative of actual aquifer conditions was entering the well. Groundwater parameter stabilization was characterized by three successive readings within 10%. Before a sample was collected, the water level in the well was allowed to recharge to at least ' 80% of its initial level. All water removed from the monitoring well and not used as a sample was placed into a 55-gallon DOT approved container that was properly labeled and temporarily stored on-site. ' The groundwater samples were obtained utilizing the Waterra pump and dedicated tubing. ' Extreme care was exercised while collecting samples to prevent agitation of the water moving in the tubing. Water samples were transferred from the tubing into 40-m1 VOA vials, preserved with hydrochloric acid or trisodium phosphate, while minimizing sample aeration during transfer of the sample. All samples were checked for headspace bubbles, labeled, inserted into foam holders and placed into a cooled ice chest for transport to the laboratory. ' The sampling technician wore disposable gloves while collecting all samples. A chain of custody document, listing all samples collected and their intended analyses, accompanied the samples from the field to the laboratory, thereby providing a means to track the movement of the samples and ensure their integrity. i