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FIELD METHODS AND PROCEDURES <br /> 1 0 GROUND WATER AND LIQUID-PHASE PETROLEUM__HYDROCARBON <br /> DEPTH ASSESSMENT <br /> A water/petroleum interface probe was used to assess the thickness of liquid-phase petroleum <br /> hydrocarbons (LPH), if present, and a water level indicator was used to assess ground water depth in <br /> monitoring wells that do not contain LPH Depth to ground water was measured from the top of each <br /> monitoring well casing The tip of the water level indicator was subjectively analyzed for LPH sheen <br /> All measurements 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 <br /> length past the air/liquid interface The bailer was then retrieved and the sample contained within the <br /> bailer was 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 <br /> of the purge water had stabilized and a minimum of three to four well volumes of water had been <br /> removed Ground water removed from the wells was stored in 55-gallon barrels at the site The barrels <br /> were labeled with corresponding monitoring well numbers and the date of purging After purging, <br /> ground water levels were allowed to stabilize A ground water sample was then removed from each of <br /> the wells using a disposal bailer If the well was purged dry, it was allowed to sufficiently recharge and <br /> a sample was collected Samples were collected in air-tight vials, appropriately labeled, and stored on <br /> ice from the time of collection through the time of delivery to the laboratory A chain-of-custody form <br /> was completed to ensure sample integrity Ground water samples were transported to the laboratory and <br /> analyzed within the EPA-specified holding times for the requested analyses Purge water will be collected <br /> from the storage barrels in a vacuum truck and transported to an appropriate facility for treatment and/or <br /> disposal <br /> LRP187 CAC <br />