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ARCADIS GERAGHTY&MILLER <br /> collected from the product piping trench between the dispenser islands D-I and D-3 at <br />' concentrations of 150 and 0 81 milligrams per kilograms of soil (mg/kg), respectively <br /> This trench area was over-excavated, and a confirming soil sample collected from the base <br />' of the excavation Petroleum hydrocarbons were not detected in this soil sample <br /> 1 A second 130-gallon waste oil UST, that was discovered on March 2, 1992, was <br /> removed from the eastern portion of the property in May 1992 Petroleum hydrocarbons <br /> were not detected in the soil sample collected from beneath this UST <br />' Data pertaining to the UST removal were presented in GeoStrategies (GSI) <br /> Report No 782701-1, Tank Removal Observation Report, dated September 11, 1992 <br /> GSI reported that the data collected during the investigation indicated that no <br /> hydrocarbons, benzene (B), toluene (T), ethylbenzene (E), xylenes (X), or ethylene <br /> dibronude (EDB) were detected in the soils beneath the UST pit of the 1992 tanks south <br />' of the station, building, the excavation pit of the 1992 waste oil UST, beneath the location <br /> of the former oil-water separator, or beneath the Iocation of the former hydraulic lifts <br />' Two out of four samples collected from the bottom of the piping trenches were nondetect <br /> for total petroleum hydrocarbons as gasoline (TPHg), BTEX, and EDB The third sample <br />' was nondetect for benzene The fourth sample, as mentioned above, indicated 81 mg/kg <br /> benzene In the two samples with TPHg detections, toluene ranged from 070 to 14 <br />' mg/kg, ethylbenzene ranged from 017 to 5 4 mg/kg, xylenes ranged from 087 to 32 <br /> mg/kg After further excavation of the trench area with the highest petroleum <br /> hydrocarbon concentrations, an additional sample taken at the bottom of the excavation <br /> was nondetect for TPHg, BTEX, and EDB <br /> In October 1993, GSI drilled eight on-site exploratory soil borings (U-A through <br /> U-H, Figure 2-3) in the locations of both the 1967 and the 1992 USTs, the former product <br /> dispenser islands, and the former hydraulic lifts, as part of UNOCAL's pre-divestment site <br />' 5 <br />