ARCHIVED REPORTS XR0000153 - Laserfiche WebLink

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1. Additionally examine the vertical distribution of petroleum hydrocarbons in soil beneath the former tank location. 2. Assess the impact of soil vapor extraction efforts on soil quality. 3. Further identify the subsurface geology surrounding the site 4. Evaluate all results and recommend any further action at the site that may be warranted. S. Coordinate all field work with Pacific Bell as well as local and regional regulatory ' agencies. ' To accomplish these goals, IT drilled two soil borings (Figure 3 and Appendix A). The soil boring locations were identified to examine the vertical distribution of petroleum hydrocarbons beneath the former diesel tank and to assess the impact of the soil vapor extraction efforts completed at the site. Borings were installed adjacent to the former vapor well where the greatest diesel concentrations had been previously encountered. A mobile lab was used to analyze soil samples collected from the open boreholes. The total borehole depth was 40 feet below grade. Where applicable. field investigation methods followed the Tri Regional Board Staff Recommendations for Preliminary Evaluation and Investigadons of Underground Storage Tank Sites, 10 August 1990. The following section describes the procedures used in ' completing the investigation. ' 2.1 Drilling Methodology IT notified Underground Services Alert (USA) three working days before starting drilling activities. In addition IT representatives studied utility maps and contracted an independent line locating service to help insure that drilling activities did not encounter any underground utilities. Each day, prior to field work, the field geologist or IT site representative conducted a tailgate safety meeting to ensure proper site safety precautions were identified and also to conform to the IT site specific health and safety plan. MV 12-08-93/ENG193-1065.nbr 2