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i <br /> concentrations of salt and alkali. Stream-channel deposits <br /> m- of sand and gravel are also included (Hotchkiss and Balding, <br /> 1971 ) . <br /> This study focuses on the water quality in the "shallow <br /> water-bearing zone" of Hotchkiss and Balding ( 1971 ) . <br /> Groundwater within this zone occurs less than 10 feet below <br /> grade over most of the Tracy area. The flood-plain deposits <br /> of the shallow water-bearing zone have well developed soil <br /> profiles and, consequently, poor permeability. The base of <br /> the shallow zone is poorly defined and probably is from 5 to <br /> 25 feet below land surface. <br /> Based on monitoring data from a nearby facility, regional <br /> groundwater flow in the shallow water-bearing zone beneath <br /> WA the Heinz plant is to the north. <br /> 3.0 FIELD INVESTIGATION <br /> 3. 1 Purpose and Scope <br /> On September 14, 17th through 21st, and 24th the former tank <br /> � & pit area was excavated with a backhoe to remove as much <br /> contaminated soil as possible. The lateral extent of the <br /> excavation was 10 feet west and east, 8 feet south and 32 <br /> feet north of the former tank pit. All observable <br /> contaminated soil was removed in tha east, and west <br /> directions. High voltage utilities and lighting structures <br /> prevented complete excavation of all contaminated soils <br /> above the water table along the northern and southern <br /> boundaries of the excavation. However, it is clear that the <br /> vast majority of the contaminated soil in the unsaturated <br /> � . zone has been removed. The water table was encountered at a <br /> depth of 9. 5 feet below grade (Figure 2) . Approximately 800 <br /> cubic yards of soil were removed from the pit. Sixteen soil <br /> pile composites were collected from this excavated material. <br /> g1 Also, soil samples were collected at the bottom of the pit <br /> along the side walls in seven locations. These soil samples <br /> were submitted to B.C. Laboratories for analysis. The <br /> laboratory results for the samples are included in Appendix <br /> I and are summarized in Table 3. <br /> A composite of the sixteen composites submitted to B.C. <br /> Laboratories was analyzed for soluble and total metals. The <br /> analyses showed non--detectable to below the regulatory <br /> criteria set forth by Title 22, Article II of the California <br /> Administrative Code. This denotes soil as non-hazardous <br /> (see Taole 3) . <br /> On October 2, 1990, a composite from each soil pile (six) <br /> were collected and submitted to Sequoia Analytical <br /> Laboratory. A single composite of these six samples was <br /> �" 3 <br />