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r •. �r per_ Y _ j December 11, 1991 Beacon Service Station No. 492, Manteca, California A traffic-rated cast-aluminum utility box with a PVC apron will be placed over the wellhead and set in concrete flush with the surrounding concrete pad. This box has a watertight seal to protect against surface water infiltration and is opened with a special wrench. The design of the box discourages vandalism and reduces the possibility of accidental disturbance to the well. Well l)evelo in and Samplin The well will be developed using a combination of surging and pumping. This method effectively ref.,ioves sediment from the sand pack and the well. Following ground-water recovery to static conditions,an initial water-level measurement will be taken using a Solinst electric water-level indicator. Water samples for subjective analyses will be collected from the air-fluid interface by lowering approximately half the length of a clean Teflon bailer past the interface. The bailer will be retrieved and the water sample examined for floating product,sheen, or other subjective evidence of hydrocarbons. If free product is present,the well will not be purged or sampled. If free product is not present, approximately 3 to 4 well volumes of water will be purged from the well using a submersible pump until the physical parameters of the water (pH, conductivity, and temperature)stabilize. After the well is allowed to recover to their static water level, a ground-water sample will be collected by lowering a clean Teflon bailer past the air-water interface. The bailer will be retrieved and the sample slowly transferred to a laboratory-cleaned,40-milliliter glass vial containing hydrochloric acid as a preservative, sealed with Teflon-lined lids, labeled, and immediately placed in iced storage. A Chain of Custody Record will be initiated by the field geologist and will accompany the water samples to the laboratory. 86102-7W 9