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08 November 2002 AGE-NC Project No.02-0918 Page 5 of 9 surveyed a reference point on the top of each ground water monitoring well casing at the site to the nearest 0.01-foot relative to the City of Stockton Bench Mark No. 182,at an elevation of 15.77 feet above mean sea level(MSL).The results of the monitoring well survey are contained in Table 4.The surveying report(Baumbach&Piazza) is presented in Appendix B. 3.6. QUARTERLY WELL MONITORING PROCEDURES The initial ground water monitoring event was performed on 02 July 2002.Ground water monitoring activities included the measurement of ground water levels and collection of ground water samples. 3.6.1. Well Monitoring and Evacuation A Solinst water level meter was used to measure the depth to ground water to the nearest 0.01-foot in the three wells relative to the tops of the well casings.The ground water elevations and gradient were determined from these data(Table 1). After recording water level measurements, disposable plastic bailers were used to purge the wells of standing water; between 12 and 20 gallons of water(a minimum of 3 casing water-volumes per well) were evacuated from each well. Ground water temperature, pH and conductivity were measured at regular intervals during purging using an Oakton water analyzer.Purged ground water was containerized in properly labeled DOT-approved model 17H 55-gallon drums and was stored on-site. Field sheets and data are included in Appendix C. 3.6.2. Collection and Analysis of Ground Water Samples Prior to collection of ground water samples,the depth to ground water was measured in each purged well to ensure that a minimum of 80%of the well volume had recharged.Afterwards,water samples were collected from each well using a new disposable plastic bailer. Each water sample was transferred into three chilled 40-m1 volatile organic analysis (VOA) vials containing 0.5 ml hydrochloric acid(18%)as a sample preservative.The samples were labeled and placed in a chilled container for transportation under chain-of-custody to MAI. Each sample was analyzed for: • TPH-g by EPA Method 8015 Modified and • BTEX and oxygenated fuel additives MTBE, TBA, DIPE, ETBE, TAME, EDB and 1,2-DCA in accordance with EPA methods 8260 Modified. Advanced GeoEnvironmentA Inc.