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Limited Soil and Groundwater Report-05/24/99 Page 8 Western 0,1,11 Spreading1preal,ng Site Project No 024 98 6.0 SI'Z'E SOILS The site soils encountered beneath the site property during drilling consisted of brown silty sand to a depth between 8 to 9 314 feet bgs followed by an underlying layer of grey to brown sand, with the exception of boring B-3,which did not contain a sand seam at that elevation Below these layers of soil at a depth of between 12 and 13 feet bgs, a brownish-grey to brown clayey sand to silty sand was encountered to a depth of approximately 40 feet bgs However, a grey sand layer approximately 9 feet thick(at B-2) and a half-foot thick grey silty clay layer(at B-4), were encountered followed by a grey silty clay and grey-brown sand layer(at B-2) or a grey sand, grey-brown silty sand, and light ' grey sand layer (at B-4) At the time of sampling, petroleum hydrocarbon odors and soil discoloration were noted in the soil samples collected from borings B-1, B-2, and B-4 commencing at a depth of approximately 14, 4, and 12 feet bgs, respectively Analytical results later confirmed petroleum hydrocarbons within the soil at these three locations No indication of impacted soil was observed or confirmed by analytical results at borings B-3 and B-5 7.0 SOIL. SAMPLING A total of 20 soil samples were selected during the drilling of borings B-1 through B-5 and submitted for laboratory analysis of TPH-d, TPH-k, TPH-g, MTBE, and BTEX The soil samples for borings B-2 through B-5 were collected using a 2 '/2-foot long, 2-inch 1 D steel split-spoon sampler containing three six-inch long stainless-steel or brass liners, while soul samples for boring B-1 were ' collected using a three-inch diameter, five-foot long split-spoon sampler containing no brass liners Each sampler used was decontaminated before and after each use by using a Tri-Sodium Phosphate ' wash solution and tap water The sampler was placed down the boring and driven into the ground approximately 18-inches using a 140-pound hammer, with the exception of boring B-1, which was continuously-cored ' Soil sampling intervals and initial sampling runs were used for visual classification of the underlying soil The soil sampling intervals were generally at depths of approximately 5, 10, 15, 20, 25, 30, 35, and 40 feet bgs Soil samples not submitted for laboratory analysis were used for visual identification of the underlying lithology ' 8.0 GROUNDWATER SA1J,IPII 2MG Because groundwater was encountered in only one of the exploratory soil borings, a total of one groundwater "grab"sample was collected from boring B-4 After boring B-4 was completed, the hollow-stem augers were left in-place for approximately one hour to prevent collapsing of the borehole and to assure that a representational groundwater "grab"sample could be collected from rthe borehole Groundwater samples were collected by placing a disposable bailer down the center of the auger to allow for an in-situ water sample collection The water sample was placed in three 40 rnl VOA vials containing HCL as a preservative for TPH-g and MTBE analysis and a one-liter amber bottle for TPH-d and TPH-k analysis The sample vials were filled with the collected groundwater until they overflowed, and were then sealed with Teflon-lined septa caps so that no air was trapped in the vial or bottle Once filled, each of the samples were inverted and tapped to test for air bubbles The groundwater water samples were contained in vials approved by the US EPA and the SFBRWQCB in accordance with EPA SW 849 Each sample container was properly labeled and contained the sample number, and date of sampling