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1 0 GROUND WATER AND FREE-FLOATING PRODUCT DEPTH DETERMINATI N <br /> . A water/petroleum product interface probe was used to determine the free product thickness, if <br /> present, and a water level indicator was used to measure the ground water depth to monitoring wells <br /> that do not contain free product 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 product <br /> sheen All measurements and physical observations were then recorded in the field on separate data <br /> sheets presented in Enclosure B <br /> 260 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, disposable bailer to approximately one-half the <br /> bailer length past the air/liquid interface The bailer was then retrieved, and the sample contained <br /> within the bailer was examined for floating product and the appearance of a petroleum product 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 <br /> conductivity of the purge water had stabilized and a minimum of three to four well volumes of water <br /> had been removed Ground water removed from the wells was stored in 55-gallon barrels at the site <br /> The barrels were labeled with corresponding monitoring well numbers and the date of purging After <br /> purging, ground water levels were allowed to stabilize A ground water sample was then removed <br /> from each of the wells using a disposable bailer If the well was purged dry, it was allowed to <br /> sufficiently recharge and a sample was collected Samples were collected in air-tight vials, <br /> appropriately labeled, and stored on ice from the time of collection through the time of delivery to <br /> 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 <br /> the requested analyses Purge water will be collected from the storage barrels in a vacuum truck and <br /> transported to an appropriate facility for treatment and/or disposal <br /> LRP 100 HMB <br />