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FIELD METHODS AND PROCEDURES <br /> 10 GROUND WATER AND LIOUID-PHASE PETROLEUM HYDROCARBON <br /> DEPTH ASSESSMENT <br /> A water/petroleum interface probe was used to assess the thickness of liquid-phase petroleum hydrocarbons <br /> (LPH), if present, and a water level indicator was used to assess ground water depth in monitoring wells <br /> that do not contain LPH Depth to ground water was measured from the top of each monitoring well <br /> casing The tip of the water Ievel indicator was subjectively analyzed for LPH sheen All measurements <br /> and physical observations were then recorded in the field on separate data sheets <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 <br /> sample was retrieved by gently lowering a clean, disposal bailer to approximately one-half the bailer length <br /> past the air/liquid interface The bailer was then retrieved and the sample contained within the bailer was <br /> examined for floating LPH and the appearance of a petroleum sheen <br /> 3.0 MONITORING WELL DEVELOPMENT, 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 <br /> with corresponding monitoring well numbers and the date of purging After purging, ground water levels <br /> were allowed to stabilize A ground water sample was then removed from each of the wells using a <br /> disposal bailer If the well was purged dry, it was allowed to sufficiently recharge and a sample was <br /> collected Samples were collected in air-tight vials, appropriately labeled, and stored on ice from the time <br /> of collection through the time of delivery to the laboratory A chain-of-custody form was completed to <br /> ensure sample integrity Ground water samples were transported to the laboratory and analyzed within the <br /> EPA-specified holding tunes for the requested analyses Purge water will be collected from the storage <br /> barrels in a vacuum truck and transported to an appropriate facility for treatment and/or chsposal <br /> LRP004 809 <br />