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Wort:Plan-Soil and Groundwater investigation i.r New Jerusalem Scbool October 26,1995 Page-4- 3.6 MONITOR WELL SURVEYING,DEVELOPMENT,AND SAMPLING Condor's licensed land surveyor will determine the location and relative elevation of the well collars following the installation of the monitor wells. The well collars will be surveyed with a vertical accuracy of 0.01 foot and horizontal accuracy of 1.0 foot. The measuring point for water-level measurements will be marked on each well collar. The groundwater gradient will be estimated using the survey information and the depth to water measurement in each well. The wells will be gauged during periods of low and high tide to evaluate tidal influences on the groundwater gradient. At least 48 hours following construction, the monitor wells will be developed by surging and bailing the groundwater in each well until the discharge water is free of sediment (clear to the unaided eye). The monitor wells will be purged until the temperature, electrical conductivity and pH of the water has stabilized. All well-development equipment will be cleaned prior to use in each well by washing in a solution of laboratory-grade, non-phosphate detergent and hydrocarbon-free water, and double rinsing with hydrocarbon-fi-ee water. The purge water discharged from the wells during development will be placed in 55-gallon drums, sealed, labeled, and left on site to await disposal pending results of laboratory t✓ analysis. Groundwater samples will be collected at least 48 hours following development of the monitor wells. L, Prior to sample collection, the static water level in each well will be measured to the nearest 0.01-foot with a battery-operated, water level meter. A disposable bailer will be lowered into each well to check for floating product, petroleum odors and/or sheen. If floating product is present, the thickness will be measured.�Laboratory samples will not be collected from wells that contain floating product. The monitor wells will be purged using a clean, disposable bailer until the temperature, electrical conductivity and pH of the water has stabilized. At least three casing volumes of water will be purged t� from each monitor well. The purged water from each well will be containerized in a 55-gallon drum and left on site pending analytical results. Each well will be allowed to recover to at least 80% of its pre-purge water level before sampling. The groundwater samples will be collected with clean, disposable bailers. Each water sample will be gently drained from the bailer to three 40-m1 glass, volatile organic analyses (VOA) vials using a bottom- emptying device. Each vial will be labeled for sample identification and placed in a cooler chilled with Blue Ice. Upon completion of the fieldwork, the water samples will be delivered under chain-of-custody 4 procedures to GeoAnalytical Laboratories,Inc., in Modesto, California. 3.7 LABORATORY ANALYSIS �. The soil samples collected from the borings will be analyzed for methyl tertiary butyl ether (MTBE), benzene, toluene, ethyl benzene, and total xylenes (BTEX) by EPA Method 8020, and for TPH-G by Method 5030/LUFT. The groundwater samples collected from the borings and monitor wells will be analyzed for TPH-G by Method 5030/LUFT, for BTEX by EPA Method 602, and for gasoline oxygenates/additives by EPA Method 8260. The gasoline oxygenates/additives include Methyl tertiary- Butyl Ether (MTBE), Ethanol, tertiary-Butanol, Di-isopropyl ether (DIPE), Ethyl tertiary-Butyl Ether (ETBE), and tertiary-amyl Methyl Ether (TAME). Any soil samples that contain MTBE at or above the laboratory reported detection limit using EPA Method 8020 will be subsequently analyzed by EPA Method v L+ CONDOR W