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iu¢IMGE0.5 GES�Ea5CON5lx1AN 5 ' Since the performance of the Phase II investigation, monitor wells MW-2 and MW-3 have gone • dry because the regional water table elevation has dropped In order to properly assess ' groundwater beneath this portion of the site, replacement wells were necessary. ' 3.0 SUMMARY OF FIELD ACTIVITIES t Soil sampling and monitor well abandonment, installation and development were completed during 10 to 12 July 1995 and groundwater sampling was completed 26 July 1995. All work was performed under the supervision of a California Registered Geologist in accordance with ' the WESTON Work Plan and Work Plan Amendment dated 9 March and 22 June 1995, respectively. Additional requirements were defined by the PHSEHD in their letter dated 28 March 1995 The following discussion summarizes the investigation program while a detailed field report is presented in Appendix A ' 3.1 MONITOR WELL ABANDONMENT ' One dry monitor well (MW-3) was abandoned during this field effort MW-2, which is also dry, was originally planned for abandonment in the 9 March 1995 Work Plan, however, the well ' was not abandoned at the request of PHSEHD MW-3 was abandoned by placing a bentonite-cement grout mixture from the bottom of the well ' via a tremie pipe The well was grouted and all pressure was supplied by the weight of the grout column. The drill ng was unable to form a pressure seal over the well because the well ' was beneath an overhang of the building The well casing was refilled to the surface as necessary, and the surface patched with a concrete mixture 3.2 MONITOR WELL INSTALLATION AND SOIL SAMPLING Two replacement monitor wells, MW-2A and MW-3A, were installed to depths of 60 and 57 feet below ground surface (bgs), respectively, at the locations shown on Figure 2 Soil sampling ' and well installation procedures are discussed in the Field Report, Appendix A ' Soil samples were collected at 5-foot intervals for field screening and lithologic description Four soil samples from MW-2A and three soil samples from MW-3A were submitted for chemical analysis based on field conditions and screening results Soil samples were submitted for chemical analysis of total petroleum hydrocarbons as gasoline ('IPH-g) and diesel (TPH-d) using EPA Method 8015m and for benzene, toluene, ethyl benzene, and xylene (BTEX) using urxOlEC SZANj0Q%MAPHASE M 3 29^"o""M