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2.0 SCOPE OF WORK The objectives of this investigation were to further assess the lateral extent of impacted groundwater and to expand the on-site groundwater monitoring network to the northeast, downgradient of the former USTs To achieve these objectives, one additional on-site ' groundwater table monitoring well was permitted, installed, surveyed, monitored and sampled 21 Project Planning Prior to initiating fieldwork, a site-specific health and safety plan addendum was prepared ' according to 29 CFR 1910 120 The health and safety plan included safety procedures, chemical hazard information, site safety officers, and preferred medical emergency locations On November 28, 2001, PHS/EHD issued permit SR#0028187 to complete the on-site monitoring well A copy of the approved permit is included in Appendix A At least two working days prior to ' drilling, PHSIEHD and Underground Service Alert (USA) were notified so that regulatory and utility clearance inspections could be scheduled Underground utilities were marked by USA member utilities under USA Ticket#363463 22 Groundwater Monitoring Well Installation On November 30, 2001, under the supervision of Ramage Environmental, Mitchell Drilling (C-57 License#672617) installed one on-site groundwater table monitoring well (MW-4) to expand the groundwater monitoring network to the northeast, downgradient of the former USTs (Figure 2) ' 2 2 1 Monitorim Well Construction, Development and Survey ' Mitchell Drilling installed the well in an 8-inch diameter soil boring, drilled to a depth of 87 feet bgs, using a truck-mounted CME 75 drill ng and hollow stem augers The well consisted of 20 feet of two-inch diameter, Schedule 40, flush-threaded and machine-slotted (0 020-inch) polyvinyl chloride (PVC) well screen, spanning from approximately 67 to 87 feet bgs Blank PVC casing was threaded into the top of the well screen and extended to the surface A filter pack of#3 ' graded and washed silica sand was placed through the hollow stem augers as they were slowly retrieved and until the sand pack reached approximately two feet above the top of the screened interval (i e , 65 feet bgs) 11