ARCHIVED REPORTS_XR0010479 - Laserfiche WebLink

Home Browse Search

I 3.0 SCOPE OF WORK 3.1 Soil Borings On December 8-14, 1998, five soil borings (MW-1, MW-2, MW-3, MW-4 and B-2) were drilled to depths of90-100 feet bgs using a CME-75 drill rig equipped with 8-inch diameter hollow- stem auger The locations of the borings are illustrated in Figure 2, Site Plan Soil sampling was attempted at 5-foot intervals in each boring using a California Modified split spoon sampling device Samples were field screened using an OVM Subsequent to sampling, sample tubes retained for possible later analysis were immediately sealed and placed in an ice chest containing blue ice Sampling equipment was washed and rinsed after each sampling event Drill spoils were stored on site in 55-gallon drums Field observations of soil samples obtained and conditions encountered during drilling at the Site were recorded on Bonng Logs, which are presented in Appendix A Soil samples were transported under Chain-of-Custody protocols to BSK Analytical Laboratories for subsequent analysis Twenty-five soil samples, including four from boring MW-1, six from boring MW-2, three from boring MW-3, three from boring MW-4 and nine from boring B-2 were analyzed for TPHg and BTEX using EPA Method 8015/8020 The samples were analyzed for fuel oxygenates using EPA Method 8260 A Hydropunch® was used to obtain a groundwater sample from boring B-2, which was not converted to a monitoring well The groundwater sample was analyzed for BTEX and fuel oxygenates using EPA Method 8250 3.2 Monitoring Well Construction Borings MW-1, MW-2, MW-3 and MW-4 were converted to 2-inch-diameter, PVC monitoring wells Each well was installed to a depth of approximately 90 feet bgs, with 0 020-mch screen installed from 70-90 feet bgs The annular space of each well was packed with a#2/12 graded sand filter-pack to about 2 feet above the screened interval An approximately 3-foot-thick bentonite seal was placed above the sand and hydrated with potable water to prevent the cement grout from entering the filter media The remaining annulus was backfilled with cement grout to the existing grade Traffic-rated steel utility boxes were placed over the wells The boxes were set in concrete such that surface water drains away from the well covers The utility boxes are constructed with rubber seals to reduce the potential for infiltration of surface water Monitoring well completion details are included in Appendix A ' tntenm Report-07400178-May 1999 3 r �