Laserfiche WebLink
methodologies. Laboratory results are summarized in Table <br /> 1 . Analytical data sheets and chain-of-custody documentation <br /> are included in Appendix IV. <br /> 3 .2 Soil Contamination <br /> Analytical results of soil samples collected from boring <br /> ASS-1 showed significant concentrations of gasoline <br /> hydrocarbons at 15. 5 and 21 feet along the boring length. <br /> This corresponds to approximately 11 and 15 vertical feet <br /> below grade, at the fill end of the tank. Laboratory <br /> ' analysis of soil samples collected from ASB-2 at the <br /> opposite end of the tank recorded very low levels of <br /> contamination. The absence of significant contamination at <br /> ' this end of the tank indicates that soil contamination is <br /> somewhat localized at the fill end of the tank. Soil <br /> contamination at the site is likely due to overspillage <br /> during routine filling of the tank. To fully define the <br /> ' vertical and lateral extent of soil contamination, <br /> additional investigation is recommended. Since groundwater <br /> reportedly occurs between 45 and 50 feet below grade, and <br /> ' since it is likely that the current water table is even <br /> lower; at least 30 feet of soil as present between the <br /> deepest sample and the groundwater table <br /> ' 4.0 RECOMMENDATIONS <br /> 4. 1 Additional soil investigation <br /> Workscope/methodology <br /> ' To fully define the vertical and lateral extent of <br /> significant soil contamination, the following scope of work <br /> is proposed: <br /> ' 1. Three soil borings will be drilled to a depth of <br /> approximately 30 feet below grade or to a depth below <br /> which no contamination is evident based on field <br /> ' observations ( PID readings, discoloration, odors) . The <br /> location of proposed borings are shown on Figure 4. <br /> These borings will be angled if necessary to avoid <br /> ' overhead lines. <br /> 2. Drilling will be conducted by Spectrum Exploration, Inc. <br /> (C57-51-2289 ) using a hollow stem auger drill rig. A <br /> ' field geologist will continuously log all drill cuttings <br /> and soil samples utilizing the Unified Soil <br /> Classification System. Descriptions of soil types <br /> ' encountered, sample collection intervals, and boring <br /> abandonment details will be recorded on boring/well logs <br /> and included within the assessment report. Cored soil <br /> samples will be collected at five foot intervals in <br /> accordance with WaterWork' s Quality Assurance/Quality <br /> Control Plan (QA/QC) (Appendix III ) . Selected soil <br /> samples will be submitted for laboratory analysis . <br /> 4 <br />