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UPS <br /> July 15, 1992 <br />' Job No. 074-013 <br /> Page 2 <br /> together with sample locations and designations on Plate 4, Stockpile Sample Location <br /> Plan. Laboratory chemical data and chain-of-custody forms are presented in the <br />' Appendix. <br /> BACKGROUND <br /> GENERAL <br /> Two underground tanks were removed from the site by others prior to our <br /> involvement. A 550-gallon waste-oil tank was removed from the subject excavation; <br /> a 10,000-gallon gasoline tank was removed and replaced with a new diesel tank at <br /> a second location shown on Plate 2. Groundwater Technology provided consulting <br />' services during the described work. We were retained to address remaining issues <br /> which included closure of the waste-oil tank excavation and characterization of soil <br /> stockpiles. Background information regarding these two issues is discussed separately <br /> • below. <br /> WASTE OIL TANK <br />' During the earlier waste-oil tank removal work performed by others, one soil sample <br /> was obtained at a depth of about 12 feet. The sample was analyzed for BTEX <br /> (benzene, toluene, ethylbenzene and xylenes), TPH (total petroleum hydrocarbons) as <br /> both diesel and motor oil, priority pollutant volatile organics and semi-volatile organics, <br /> the CAM-1 7 list of metals and hexavalent chromium. Only slight levels of toluene, <br />' xylenes, and various metals were detected. Toluene and xylene concentrations were <br /> .027 and .0067 parts-per-million (ppm), respectively. The detected metal <br /> concentrations were generally within expected background levels, although the <br /> concentrations of barium, copper, nickel and vanadium were equal to or exceeded the <br /> California Code of Regulations, Title 22 Soluble Threshold Limit Concentrations <br /> (STLC's). Based on the described data, SJCEHD required that additional excavation, <br />' sampling and testing be performed to confirm "clean" limits. <br /> SOIL STOCKPILES <br /> Groundwater Technology obtained three samples from the stockpiled soil removed <br />' from the gasoline tank excavation: one from soil excavated during actual tank <br /> removal and two from additional soil removed during follow-up excavation work. The <br /> initial sample was analyzed for TPH as gasoline, BTEX, total lead, organic lead and <br /> ethylene dibromide (EDB). The results from the initial sample testing revealed 37 ppm <br /> ■ Geotechnical <br /> a <br /> nmn r.1 � <br />