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r �sN bearing zone have well developed soil profiles and consequently poor permeability. The base of the shallow zone is poorly defined and probably is from five to twenty feet below ground surface. The qualify of the shallow groundwater in the Tracy area is of generally poor quality 1 4.0 INVESTIGATIVE METHODS AND PROCEDURES 4.1 Soils ' To assess the lateral and vertical extent of soil contamination beneath the site RESNA drilled eleven shallow soil borings and 3 deeper borings in the tank and product line areas. The shallow ' borings were drilled to 7 feet below grade (Figure 3) using a 2 inch solid flight auger. The deeper borings were drilled to depths of 20 feet below grade and completed as groundwater ' monitoring wells. ' All borings were sampled at 5.5 or 6 5 feet using a California modified split-spoon sampler with brass liners. The material from one sample nng was described and field screened with a photoionization detector (PID) for possible volatile organic content. The second ring was sealed at each end with Teflon tape and a plastic cap. The cap was sealed with duct tape and the ' sample was preserved on ice and transported under strict chain-of-custody procedures to Sequoia Analytical Laboratory, a State certified laboratory 1 Between sampling events, equipment was cleaned using a three bucket wash system. In this ' system, the rings and samplers were scrubbed with a brush in a bucket of tap water and detergent, then rinsed in a bucket of tap water and a final rinse of distilled water i One soil sample from each boring was submitted for laboratory analysis All samples were analyzed for BTEX, and TPHG by EPA methods $02018015 respectively. The sample collected near tank pit 2 (the waste oil tank) was also analyzed for lead, cadmium, zinc, and chromium 1 by EPA methods 7421 and 6010 respectively. R-012792 LF 3 1