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enVIYOSo <br /> Task 2 - Soil and Ground Water Sampling During Tank Removals <br /> Soil samples will be collected from beneath the USTs per Tri-Regional Guidelines. A copy <br /> of these guidelines is included in Appendix A. If ground water is encountered in the tank <br /> pit during UST removal activities, one water sample will be collected from the excavation <br /> pit for chemical analysis. <br /> If it is necessary to remove ground water from the excavations, a vacuum truck will be <br /> used, and the water transported for recycling at Shell's Martinez Manufacturing Complex <br /> located in Martinez, California. Vacuum trucks will be provided by Allwaste of Martinez, <br /> California. <br /> Task 3 -Piping Trench Sampling <br /> Piping associated with the existing USTs will be removed. One soil sample will be <br /> collected from piping trenches for every 20 lineal feet of piping. <br /> Task 4 -Chemical Analysis of Soil and Ground Water Samples <br /> Soil and water samples collected from the tank and piping excavations will be sent to a state <br /> of California certified laboratory for chemical analysis for Total Purgeable Petroleum <br /> Hydrocarbons (TPPH) according to EPA Method 8015 (Modified),BTEX compounds <br /> according to EPA Method 8020, Total Lead according to EPA Method 7421 and methyl- <br /> tertiary-butyl-ether(MTBE) according to EPA Method 8020. Chemical analytical results <br /> will be requested on a 24-hour turnaround time frame to expedite this project. <br /> Task 5 -Over-excavation <br /> Based on the results of previous investigations performed at this site, it is not expected that <br /> over-excavation beneath the tank complex or product piping trenches will be necessary. <br /> However, if petroleum hydrocarbons are detected in soil samples collected from beneath <br /> the USTs or product piping, over-excavation of soils may be performed. An Enviros <br /> geologist will be present on-site to observe field conditions and direct the excavation <br /> contractor in the removal of soils, and to document field observations, if necessary. The <br /> field geologist will screen excavated soils and stockpile soils appropriately based on field <br /> observations. <br /> Plate 2 shows the area which may be over-excavated. This extent of this is considered to <br /> be a worst case scenario, as site data available to date suggest that no over-excavation will <br /> be necessary. <br /> The total soil volume to be generated based on this estimate is 5328 cubic yards. <br /> Calculations performed to determine this volume are presented in Appendix B. <br /> The actual extent of over-excavation (if performed) around the peripheral edge of the tank <br /> pit and along piping trenches will be determined in the field by the Enviros geologist. <br /> Over-excavation will be performed in areas as warranted based on visual observations <br /> and/or screening of soils using an organic vapor meter. Confirmation samples will be <br /> 96378 3 <br />