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Geological Technics Inc. Page 2 Groundwater Monitoring Report Project No, 989.2 November 14,2003 fluctuate with groundwater elevation and that the overall MTBE concentration has ' decreased over time (Chart: MW-6). i 1.0 GROUNDWATER MONITORING 1.1 Groundwater Sampling ' On September 2, 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%. All water removed from the monitoringwell and not used as a sample was laced into a 55- P P gallon DOT approved container that was properly labeled and temporarily stored on-site. r The groundwater samples were obtained utilizing the Waterra pump and dedicated tubing. ' Extreme care was exercised while collectipg samples to prevent agitation of the water moving in the tubing. Water samples were transferred from the tubing into 40-10 VOA vials, preserved with hydrochloric acid, while minimizing sample aeration during transfer of t 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. 1.2 Laboratory Analyses The groundwater samples collected on September 2, 2003, were delivered to Sherwood ' Labs (Department of Health Services Certification No. 1400), of Hilmar, California, for the following analyses; ' • Benzene, toluene, ethylbenzene and xylene (BTEX by EPA method 802018015(m))