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ATTACHMENT C FIELD AND LABORATORY PROCEDURES Drilling and Monitoring Well Installation Procedures The monitoring wells will be drilled by a licensed drilling contractor using hollow-stem auger drilling equipment Soil samples for logging and chemical analysis will be collected at 5-foot depth intervals or at any lrthologic change noted during drilling. Samples will be collected using a split-spoon sampler with brass liners driven into the soil beyond the tip of the augers The depth of the monitoring wells will be based on static water level and geologic conditions on site, but is expected to be approximately 60 feet below the ground surface Soil samples for chemical analysis will be retained in brass liners, capped with Teflon sheets and plastic end caps and sealed in clean plastic bags, and transported on ice to a state-certified laboratory for chemical analysis Soil samples collected at 5-foot depth intervals will be analyzed in the field for organic vapors using a photo-ionization detector The test procedure involves measuring approximately 30 grams from an undisturbed soil sample, placing this subsample in a clean glass jar, and sealing the jar with aluminum foil secured under a ring-type threaded lid The jar as warmed for approximately twenty minutes, then the foil is pierced and the head-space within the lar is tested for total organic vapor, measured in parts per million as benzene (ppm, volume/volume) Results of these tests will be used to assist in selection of samples for laboratory analysis The borings for the wells will penetrate a maximum of 15 feet into the water-bearing zone taking care not to penetrate any aquntard underlying the first water-bearing zone, encountered These borings will be converted to groundwater monitoring wells with the installation of 2-inch diameter, Schedule 40 PVC casing and 0 02-inch factory-slotted screen Screen will be placed through the entire saturated section, extending approxi- mately 5 feet above the static water level A 2 X 16 graded sand pack will be placed in the annular space across the screened interval, and will extend approximately 2 feet above the screen Screen size and filter pack size have been determined based on previous well constructions on site. Approxunately two feet of bentonite will be placed above the sand pack followed by a concrete seal to the ground surface A locking cap 3104001\WORKPLN C— 1 August 6, 1993