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GROUND WATER INVESTIGATION WORK PLAN <br />BULK TERMINALS SITE, PORT OF STOCKTON, STOCKTON, CALIFORNIA _ <br />MW-6 and 7— are located upgradient from the bulk materials stockpiles to characterize <br />background ground water quality. <br />MW-8 and 9 — are located downgradient of all bulk terminal site operations to assess <br />persistent impacts to ground water quality, if any, associated with the <br />stockpiling and handling of bulk materials. These wells are anticipated to <br />monitor shallow ground water for potential sulfur and sulfate, petroleum <br />hydrocarbons, nickel and vanadium and copper. <br />3.2.2./ Monitor Well Construction <br />Boreholes for the monitor wells will be advanced using hollow-stem auger drilling equipment, <br />and the wells constructed within the hollow-stem auger. Soil samples will be collected <br />continuously in a 2-inch diameter split-spoon sampling device. The soil samples will be <br />described and logged as detailed in Task 2 above. Soil samples collected from the borehole are <br />not proposed for laboratory analysis. <br />Monitor wells will be screened in the sandy aquifer materials as described in Phase 1, above. <br />The anticipated total depth of the borings for monitor wells completed in the shallow sandy <br />aquifer is from 25 feet to 35 feet bgs; this depth will be known with greater accuracy following <br />completion of Phase 1. <br />The monitor wells will be constructed using 2-inch diameter schedule 40 PVC. The screen will <br />be 0.010-inch factory-slotted and will be surrounded with a sand filter pack of Lonestar #2/16 <br />sand, or similar. The sand pack will be "set" using a bailer to gently surge the water within the <br />well screen. At least 2 feet of hydrated bentonite will be placed above the sand pack to provide <br />a well seal. A cement-bentonite slurry will be placed above the bentonite seal to ground <br />surface. The well casing will be protected with concrete, and within a water tight, traffic rated, <br />locking Christy box, or similar. Figure 7 shows a schematic for a typical ground water monitor <br />well. <br />3.2.2.2 Well Development <br />All monitor wells will be developed by bailing. The development water will be monitored for <br />electrical conductivity, pH, and turbidity. When these parameters have stabilized to within 10 <br />percent of successive measurements, the well will be considered adequately developed. All <br />bailed development water will be contained in drums for proper disposal. Disposal options <br />will be identified based on the analytical results of water samples to be collected from the <br />monitor wells. <br />July 2005 Page 16 Environmental Risk Services Corp.