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07 February 1997 <br /> AGE-NC Project No 96-0266 <br /> ' Page 6 of S <br /> Analytical results of the grab ground water samples for metals are summarized in Table 4 The <br /> ' laboratory report (MAI Laboratory ID 72947 to 729613), QA/QC report and chain-of-custody are <br /> included in Appendix B <br /> 1 1 <br /> 5.4. CONCLUSIONS AND RECOMMENDATIONS <br /> 5 1 CONCLUSIONS <br /> ' Based upon the results of the subsurface investigation and historical research,AGE has the following. <br /> conclusions <br /> • Hydrocarbon-impacted soil at the site is limited to the vicinity of the former UST within San <br /> Jose Street The impacted soil was encountered in a somewhat narrow zone from depths of <br /> approximately 5 to 15 feet bsg Hydrocarbon-impacted soil was not encountered southwest, <br /> ' north or east of the former UST area <br /> • The detection of MTBE in soil samples collected from probe boring P I indicate the release <br /> !� of gasoline to be relatively recent, possibly within the past twenty years <br /> • Gasoline-impacted ground water is present around the former UST on San Jose Street The <br /> ' dissolved gasoline plume appears to extend to appioximately 50 feet northeast and 50 feet <br /> southwest from the former UST location, and has an approximate width of 40 feet Figure <br /> 3 depicts the estimated extent of the gasoline-impacted ground water <br /> • Diesel fuel-impacted ground coater appears to be limited to the southwest portion of the site, <br /> diesel fuel was not detected in grab water samples collected near the existing UST inside <br /> Building C Since diesel fuel was not known to be used or stored on-site, an off-site source <br /> of the dissolved diesel in ground water is likely <br /> • Results of historical research indicate that a Texaco bulk-oil storage facility was located <br /> ' immediately west of the site,this adjacent property may be a source of the dissolved diesel <br /> in ground water <br /> ' The background concentrations of metals in the soils at the site are represented by the two <br /> soil samples analyzed from the southern portion of the site (P2-10 and P5-15) <br /> ' • The laboratory analyses of the soil samples collected near the plating shop indicate that only <br /> low concentrations of metals are present in the shallow soil Furthermore, no significant <br /> concentrations of soluble lead were detected in the soil samples <br /> • Cadmium, chromium, lead and nickel were detected above the State of California Maximum <br /> Contamination Levels (MCL) for drinking water in both samples, zinc was detected above <br />