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iff7KLEINFELDER with subsurface utilities. Kleinfelder assumes that the proposed sampling locations will also be satisfactory to Chevron and PG&E. SOIL SAMPLING Twenty nine (29) push probes will be advanced within and near the estimated footprint area of petroleum impacted soil (Plate 1). Twenty five pushprobe locations will be advanced in a grid- like pattern within the footprint area generally based on a 75-foot grid pattern to depths ranging from surface to approximately 20 feet below ground surface (maximum estimated depth of oil impacted soil) within the surveyed footprint of the spill area. In addition to sampling within the 75-foot grid pattern, Kleinfelder is proposing approximately six additional sample locations in the assumed greatest impact areas east and northeast of the rupture site (Based on aerial photograph depicting surface oil accumulation and field observations by Kleinfelder). Kleinfelder anticipates that up to half of the pushprobe borings located in less impacted areas, will not have to be advance to depths greater than ten feet bgs. The actual total depths of the pushprobes will be based on field observations and field screening using a photo-ionization detector (PID). The PID measures ionizable compounds in air in parts per million by volume (ppmv). Therefore, based on field screening and observations, greater sampling depths may be necessary. Kleinfelder proposes collection of approximately 104 discrete soil samples from the approximately 29 pushprobe locations. Kleinfelder anticipates a minimum of two soil samples and a maximum of up to four soil samples will be collected at each probe location for potential chemical analyses. Kleinfelder proposes collection of two discrete soil samples for analyses from eight probe location in the southwest portion of the footprint area and collection of four discrete soil samples from the remaining pushprobe locations within the footprint area (See Plate 1). Eighty eight (88) of the discrete soil samples collected within the footprint area will be composited by the laboratory into 22 four-point composite samples prior to analyses. Kleinfelder is proposing that four discrete soil samples collected at each probe location (collected within the estimated petroleum impacted interval) will be composited into a 4-point composite sample by the laboratory. However Kleinfelder anticipates that in less impacted areas (where vertical impacted area is minimal), such as areas southwest of the rupture point, that more than one probe location will be needed to generate 4 discrete and petroleum impacted samples. Therefore modified compositing with more than one probe location may be necessary. Kleinfelder anticipates approximately 8 probe locations will be needed to generate four 4-point composite samples in the southwest quadrant of the footprint area. Additional sampling and analyses may be warranted if the volume of impacted soil is expected to exceed the estimated Y Y P P s 20,000 cubic yards. A total of sixteen discrete samples will also be collected including four from each of the perimeter deep pushprobe borings. Four of these sixteen discrete soil samples will be collected from a pushprobe boring in each quadrant of the spill area below the estimated contaminated area. These four soil samples will be analyzed for confirmation of field observations of"clean" soil. Please note additional confirmation soil samples will be needed during the excavation and disposal phase of the project. 02001PROP.ENV/ST04P118/DH:ss Page 3 of 8 Copyright 2004,Kleinfelder,Inc. March 22,2004