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595 East I I th Street, Tracy, CA November 8, 1993 The average depth to groundwater was reported to be approximately 8-feet below surface grade meth an inferred groundwater flow direction to the north-west with a gradient of approximately 0 003 vertical per horizontal feet In October 1993, RRM performed quarterly groundwater sampling at monitor wells MW-1 through NM- 3 Groundwater samples were analyzed for TPHg and BTEX TPHg concentrations of 5,500 (5 5 ppm)and 2,900(2 9 ppm)parts per billion(ppb) along with BTEX compounds were found at wells MW-2 and MW-3, respectively TPHg and BTEX were not detected in well MW-1 The average depth to groundwater was measured at approximately 8-feet below surface grade with an inferred groundwater flow direction to the north-east SCOPE OF WORK RRM performed the following activities 1) Power actuated hand augenng, and 2) Soil and Groundwater Sampling Details of these activities are described below PROCEDURES On October 5 &7, 1993,RRM conducted a Phase II Site Characterization The characterization consisted of augenng rune 2-inch diameter boreholes, designated SB-1 through SB-9, to depths ranging from 8 0 to I0 5 feet below surface grade Boreholes were augered using a power actuated hand auger consisting of a Bosch roto-hammer equipped with a 2-inch diameter flighted auger The auger was advanced in 3-feet intervals until groundwater was encountered Augered soils were visually inspected for lithology and field screened for total volatile hydrocarbons (TVH) using a Beckman Model 400A Total Hydrocarbon Analyzer equipped with a Flame Ionization Detector (FID) A weighted Teflon sample line connected to the FID was placed into the bottom of each borehole at approximately 3, 6, and 9 feet depth intervals to draw a TVH sample TVH concentrations were then recorded on a circular chart recorder Augenng locations mere selected based on the field data from previous site characterization reports, which were provided by MS & R The general locations of the borings were in the vicinity of and down gradient of the former UST area Figure 2, shows the soil boring locations Three additional bonngs were attempted on the Tracy Union High School property located just north of the subject site Based on TVH readings, one soil sample was collected from each borehole location Actual samples were collected between 8 0 and 10 5-feet below surface grade Sample depths are presented in Table 1 Each sample was collected into a sterile 125-inch stainless steel sample sleeve Each sleeve was then capped, labeled and placed into iced storage Instead of collecting a soil sample at boring S13-2, RRM collected a grab groundwater sample The groundwater sample was collected into a 314-inch diameter stainless steel bailer and then transferred into a preserved 40-ml VOA container All samples were transported under chain of custody documentation to Anametnx Laboratories of San Jose, California for certified analysis for TPHg and BTEX In addition, soil sample SB-3 was analyzed for Total Oil and Grease (TOG) by Friedman & Bruya Environmental Chemists of Seattle, Washington Upon completion of the characterization, each borehole was grouted to surface grade using Portland cement FINDINGS Results of the soil sample analysis data are summanzed in Table 1, and a complete laboratory analyses report is attached as Appendix A The groundirater sample data from monitor wells MW-1 through MW- 3 «hich is also listed in Appendix A, is presented in a separate quarterly groundwater monitoring report . A description of soil ltthologv including borehole depths and TVH field screening readings are presented in the field boring logs%%hich are attached as Appendix B 2