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FIELD METHODS AND PROCEDURES <br /> 1.0 GROUND WATER AND LIQUID-PHASE HYDROCARBON DEPTH DETERMINATION <br /> A water/petroleum interface probe was used to determine the thickness of liquid-phase hydrocarbon (LPH) if <br /> present, and a water level indicator was used to determine ground water'depth in monitoring wells that do not <br /> contain LPH. Depth to ground water was measured from the top of each monitoring well casing. The tip of <br /> the water level indicator was subjectively analyzed for hydrocarbon sheen. All measurements and physical <br /> observations were recorded in the field. <br /> 2.0 SUBJECTIVE ANALYSIS OF GROUND WATER <br /> Prior to purging, a'water sample was collected from the monitoring well for subjective analysis. The sample <br /> was retrieved by gently lowering a clean, disposal bailer to approximately one-half the bailer length past the <br /> air/liquid interface. The bailer was then retrieved and the sample contained within the bailer was examined for <br /> floating LPH and the appearance of an LPH sheen. <br /> 3.0 MONITORING WELL PURGING AND SAMPLING <br /> Monitoring wells were purged using a centrifugal pump or bailer until pH, temperature, and conductivity of <br /> the purge water had stabilized and a minimum of three to four well volumes of water had been removed. <br />. Ground water removed from the wells was stored in 55-gallon barrels at the site. The barrels were labeled with <br /> corresponding monitoring well numbers and the date of purging. After purging, ground water levels were <br /> allowed to stabilize. A ground water sample was then removed from each of the wells using a disposal bailer. <br /> If the well was purged dry, it was allowed to sufficiently recharge and a sample was collected. Samples were <br /> collected in air-tight vials, appropriately labeled, and stored on ice from the time of collection through the time <br /> of delivery to the laboratory. A chain-of-custody form was completed to ensure sample integrity. Ground water <br /> samples were transported to the laboratory and analyzed within the EPA-specified holding times for the <br /> requested analyses. Purge water will be collected from the storage barrels in a vacuum truck and transported <br /> to an appropriate facility for treatment and/or disposal. <br /> LRP560.TA <br />