ARCHIVED REPORTS_XR0012638 - Laserfiche WebLink

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a � 4 r i� e...6 5 8 E ttE O 5V 9 Shall oil Company Cslifnrnia 3716 Tracy Boulavard,Tracy, Delta Prolact No.10-69.011 Page 3 are believed to be single-wailed and of steel construction. The fiberglass tanks were placed in the same location as the steel tanks that were removed. A waste oil tank of unknown size was removed from the site in 1985. The location of the previous waste oil tank is unknown at this time. 2.:3 Previ us Suhsuria Inv ti lv ivi 1 Prior to tank replacement activities in 1985,Shell contracted J.H.Kleinfelder& Associates to drill four test soil borings in the vicinity of the underground storage tanks. The soil borings were drilled to a depth ranging from 11.5 to 16.5 feet below the ground surface; approximate locations are illustrated in the Kleinfelder report presented in Appendix A. In the course of their investigation, Kleinfe;der collected soil samples for classification and screening with a trace gas analyzer(believed to be an OVA). In general, Kleir►felder characterized the natural soils at the site as sand and silt. Nater was encountered in boring B-1 at a depth of approximately 11.5 feet. Gasoline hydrocarbons (presumed) were detected using a trace gas analyzer in borings B-4, B-2, and B-1 at a depth of approximately 10 feet or roughly corresponding to the bottom of the tanks and just above the detected water level. Samples collected from greater depth (i.e., below the water table) did not �_--. tituents. Petroleum hydrocarbon constituents were not found contain petroleum hydrocarbon cons in any of the soil samples screened from boring B-3. s in 1985,soil samples were collected by Cananie Following removal.of the steel underground tank Engineers, Inc., from below the three tanks. In addition, water samples were collected from the bottom of the excavation. The results are included in the analytical report prepared by Canonie Engineers (Appendix B). Samples were analyzed for total extractable hydrocarbons, benzene, toluene, xylenes, ethylene dibromide, and organo-lead. In summary, soil samples indicated concentrations of TPH between no (1 ppm) to 40 pPm in soils, and o.7 ppm in water. Organo-lead, ethylene dibromide, benzene, and toluene were below detectable levels in all soil samples analyzed. Xylenes were detected in the water sample at a concentration of 66 parts per billion(ppb)and in one soil sample at a concentration of 1.2 ppb. The depth represented by these t samples is not known. Z q ill Leak Hi forof According to Shell's-records,--no leaksorspills-have.been..reported...at this site. a source petroleum constituents detected in earlier investigations is unknown.