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FIELD MIETHODS AND PROCEDURES 1.0 GROUND WATER AND LIQMD-PHASE HYDROCARBON DEPTH ASSESSMENT A water/petroleum interface probe was used to assess the thickness of liquid-phase hydrocarbon (LPH) if present, and a water level indicator was used to assess ground water depth in monitoring wells that do not contain LPH. Depth to ground water was measured from the top of each monitoring well casing. The tip of the water level indicator was subjectively analyzed for hydrocarbon sheen. All measurements and physical observations were recorded in the field. 2.0 SUBJECTIVE ANALYSIS OF GROUND WATER Prior to purging, a water sample was collected from the monitoring well for subjective analysis. The sample was retrieved by gently lowering a clean, disposal bailer to approximately one-half the bailer length past the airfliquid interface. The bailer was then retrieved and the sample contained within the bailer was examined for floating LPH and the appearance of an LPH sheen. 3.0 MONITORING WELL PURGING AND SAMPLING Prior to sampling, the monitoring wells were purged using a centrifugal pump until pH, temperature, and conductivity of the purge water had stabilized and a minimum of three to four well volumes of water had been removed. Ground water removed from the wells was stored in 55-gallon barrels at the site. The barrels were labeled with corresponding monitoring well numbers and the date of purging. After purging, ground water levels were allowed to stabilize. A ground water sample was then removed from each of the wells using a disposal bailer. If the well was purged dry, it was allowed to sufficiently recharge and a sample was collected. Samples were collected in air-tight vials, appropriately labeled, and stored on ice from the time of collection through the time of delivery to the laboratory. A chain-of-custody form was completed to ensure sample integrity. Ground water samples were transported to the laboratory and analyzed within the EPA-specified holding times for the requested analyses. Purge water will be collected from the storage barrels in a vacuum truck and transported to an appropriate facility for treatment and/or disposal. i I.RP698.TA