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Geologicalrecknialnc. Page 3 Groundwater Monitoring Report Project No.750.2 May 13,2004 with an electrically actuated sounding tape. The water level reading was recorded to an accuracy of 0.01 foot. No floating product was detected during the monitoring event. Stagnant water in the well casing was purged using a Waterra© pump and dedicated tubing. The rate of well purging was monitored. The well was purged of at least three casing volumes until the groundwater parameters (temperature, conductivity and pH)had stabilized (Appendix C) 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 well's water level was allowed to recharge to at least L80% of its initial level. All water removed from the monitoring well and not used as a sample was placed in a 55 gallon DOT approved container that is properly labeled and temporarily stored on-site. A Waterra D pump and dedicated tubing were used to collect each sample. Extreme care was exercised while collecting samples to prevent agitation of the water contained in the Waterra© pump. With minimal sample aeration, water samples were transferred from the pump into 40-m1 VOA vials preserved with hydrochloric acid. Each sample container was checked for headspace bubbles, identified and labeled with a unique designation, inserted into foam holders and placed in a chilled ice chest for transport to the laboratory. i All non-disposable sampling equipment was decontaminated using a steam cleaner before and between uses. Disposable gloves were used by the technician to collect all samples and were changed with each sampling event. A chain of custodydocument listing all samples, collected and their intended analyses, � g P accompanied the samples from field to the laboratory, thereby providing a means to track the movement of and ensure the integrity of the samples. Groundwater monitoring field logs are included in Appendix C. 1.3 Laboratory Analyses The groundwater samples collected on March 13, 2004, were delivered to Sherwood Labs of Hilmar, California(Department of Health Services Certification No. 1400), for analysis. The groundwater samples were analyzed for: • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX)by EPA method 8020/8015 L • Total Petroleum Hydrocarbons as Gasoline (TPH-G)by EPA method 8020/8015(M) • Fuel oxygenated compounds (MTBE, DIPS, ETBE, TAME & TBA) by EPA method 8260