ARCHIVED REPORTS XR0012580 - Laserfiche WebLink

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r !a ' ti L !,U G WATER A M' B: TINGAPRODUCT DEFTH DEMMINAIM A water and petroleum product interface probe was used to determine the thickness of free product, if present. A water level indicator.was used to determine ground water depth in each well that did not contain free product. Depth to ground water was measured from a known reference elevation point at the top of each well casing and recorded to the nearest 0.01 foot. If a free-floating product layer was not detected, the tip of the water level indicator was subjectively analyzed for product sheen. All f measurements and physical observations were then recorded on individual data syeets in the field. 2,0 IVE ANALYSIS OF JjRER In the event that free product or a sheen was detected with the interface probe or water level indicator, 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 hailer length past the airlliquld interface. The bailer was then retrieved and the sample contained within the bailer was examined for floating product and appearance of a petroleum product sheen. 3.0 MONITORYNr z MALL DEVELQI'h4E P a ND SAMPLING In the event that free product may have been detected within the monitoring well,the product would have been removed by bailing or using a centrifugal pump until product could no longer be effectively removed. In an effort to collect a representative ground water sample, monitoring wells were purged of 3 to 4 well volumes of water or until the well became dry, using a clean centrifugal pump or bailer. 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. Purge water was collected from the storage barrels in a vacuum truck and transported to an appropriate facility for treatment and/or disposal. After purging, ground water Ievels were allowed to stabilize. A water sample was then removed f_)n.each of the wells using a clean,dedicated disposal bailer. Samples were preserved in air- tight vials, appropriately labeled, and stored at approximately 4°C 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. l LRP102.HMB