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i.. §eaCogita!?ethnics Zxc. Page 5 � Well Installation,Report City of Esc alon Project No. 750.2 s January 31,2400 Now that construction work is finished at the site, a Cost Pre-Approval has been submitted to 1 the USTCUP for the completion of the all the wells on site. The central portion of the site needs to be raised by adding baserock to prevent pooling of water and well boxes need to be installed around MW-1, MW-2 and the vapor extraction wells. This work will be scheduled a as soon as cost pre-approval is received from the USTCFP. 3.0 RESULTS OF INVESTIGATION f The analytical results and field observations are discussed below. Tabular summaries of all # , analytical data are included in Appendix A, and the boring logs are included in Appendix B. A site map with monitoring well locations is included as Figure 2. i 3.1 Analytical Results I ; 1 Soil Sample,Analysis : • in summary, low to moderate levels of BTEX, TPH-G and MTBE were detected in the soil samples from MW-1. • Low levels of TBA were detected in the 55-foot sample collected froze.MW-1. • Low levels of MTBE were detected in the 15-foot soil sample from MW-2. • The soil samples tested in MW-3 was non-detect for all analytes. • Soil samples collected from VEW-1 showed only the presence of low levels of Xylene and MTBE. t ' Table I in Appendix A is a full summary of all soil analytical data collected at the site. 3.2 Geology and Field Observations The following section discusses the subjective field observations and geology documented J, during this investigation based on the interpretations of the field geologist. ° • The dominant soil type in the upper 75 feet of subsurface geologic soils investigated is sand, with fine to coarse-grained texture. t • Varying amounts of silt and silty sand were encountered from borehole to borehole. f • A couple laterally discontinuous clay lenses were encountered in a few of the boreholes. • Heaving sand was encountered at 75 feet in MW-1. • Groundwater was encountered at 5$-61. feet. The capillary fringe did not appear to j extend up very far. The soil was generally moist from the surface to the groundwater I interface. • Only low levels of contamination were noted by field evidence in the borings drilled near the former excavations, MW-1, VEW-3 and VEW-4. It appears that the infiltration of U rainwater through the open excavations washed much of the contamination from the soil. ; See Appendix B, Boring Logs for more information. x i 1 I d