WORK PLANS_CASE 1 - Laserfiche WebLink

Home Browse Search

C A M B R I A in our February 22, 2001 meeting at the RWQCB's Sacramento office, Equiva re-evaluated Cambria's October 23 and December 18, 2000 Site Investigation Work Plans. Discussions of these work plans and our revised work plan are presented below. Equiva's objective is to achieve complete delineation of petroleum hydrocarbon and MTBE impacted soil beneath the site. During the January 1999 tank removal activities and subsequent February 1999 over-excavation activities, residual petroleum hydrocarbons and MTBE remained in soil in locations near the northern group of dispensers, one location beneath piping near the station building, and in one sample along the northern edge of the former tank excavation. These locations and residual TPHg, benzene, and MTBE concentrations are presented on Figure 3 and the original site map and soil table from this investigation, which provide complete soil results, are included in Appendix A. Subsequent to UST removal and over-excavation activities, soil borings were drilled in the locations where residual petroleum hydrocarbons and MTBE were identified in soil. Boring SB-1 appears to have delineated the vertical and lateral (to the southeast) extent of petroleum hydrocarbons and MTBE in soil at the northeastern dispenser. Boring SB-2 appears to have delineated the vertical extent of petroleum hydrocarbons and MTBE in soil at the northwestern dispenser. Boring SB-3 appears to have delineated the vertical and lateral (to the west and southwest) extent of MTBE in soil at the southern dispenser and in piping sample location PL-I1. Boring SB-4 appears to have delineated the vertical and lateral (to the south) extent of petroleum hydrocarbons and MTBE in soil beneath product line sample location PL-10. Boring locations and TPHg, benzene, and MTBE results are presented on Figure 3 and the original site map and soil table from this investigation, which provide complete soil results, are included in Appendix A. Cambria is proposing additional lateral assessment of vadose soil around the northern dispenser island as discussed in our revised work plan below. Once we have completed this site investigation, we anticipate this additional data will demonstrate complete delineation of the vadose zone impact. If SJCPHS/EHD or the RWQCB do not concur with the boring locations or do not agree that these borings, if clean, would provide complete soil delineation, please contact Equiva or Cambria. Equiva is considering the use of soil vapor extraction (SVE) methods to remediate the residual petroleum hydrocarbons and MTBE in vadose soil in the northern dispenser island area. Data collected during the proposed investigation can be used .to properly locate any future SVE, wells. 1346 2