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GROUND WATER INVESTIGATION WORK PLAN BULK TERMINALS SITE, PORT OF STOCKTON, STOCKTON, CALIFORNIA over a period of 5 to 10 minutes to establish the equilibrated depth to water. Measurements will continue until the depth to water is stable to within 0.05 feet over a 5-minute period. Water samples will be collected according to the methods provided below and after measurements of depth to water are complete. 3.1.2.4 Soil Sampling As described above, the borehole will be advanced sequentially into and through each of the geologic materials: surficial materials, underlying clay layers, and sandy to silty-sand water- bearing zone. Soil samples will be collected continuously and described with regard to soil type, relative moisture, and color in accordance with the Unified Soil Classification System. Soil samples will be collected within clear acetate tubes lining the inside of the boring equipment. In the event that CPT borings are advanced in selected locations, continuous cone physical data will be collected first, and a second adjacent boring will be advanced to collect samples at targeted intervals for chemical analysis and conventional lithologic logging. Vadose zone soils will be analyzed for chemical constituents in borings C-1, C-3, C-4, C-7, C-8, C-10, C-11 and C-12. Soils will be analyzed for the contaminants associated with the adjacent potential sources, as well as for soil pH, total organic carbon (TOC) and cation exchange capacity (CEC). Soil sample intervals for potential laboratory analysis will be collected from approximately 0 to 0.5 feet, 3 to 3.5 feet, and 6 to 6.5 feet bgs. Samples from the surface and 6 feet bgs will be analyzed initially, and the 3-foot sample will be placed on hold at the laboratory pending results of the upper and lower vadose zone soils. If results indicate the need for intermediate-depth analytical data, the 3-foot sample will be analyzed. The selected soil sample intervals will be cut to length, capped at both ends, labeled, and placed in a chest containing water ice pending transport to the laboratory under standard chain-of- custody procedures. The label will identify the top of the sample interval and will include boring number, sample depth, date and time of sample collection, and sampler's initials. A field log will be recorded in the field for each boring and will include geologic descriptions and symbols, depth to water, sample intervals, and date and time of sample collection. 3.1.2.5 Water Sampling Within Borings Grab ground water samples will be collected from the first coarse-grained shallow water- bearing zone. Upon reaching the desired water-bearing material, a hydro-punch system, or 5 feet of slotted PVC screen, will be lowered into the boring to serve as temporary well casing to collect ground water samples. Ground water grab samples will be collected using either a bailer constructed of Teflon, PVC, or stainless steel, or a peristaltic pump outfitted with PVC or Teflon tubing. The samples will be collected in laboratory-supplied containers appropriate for the types of analyses specified July 2005 Page 11 Environmental Risk Services Corp.