Laserfiche WebLink
30 July 2003 <br /> • AGE-NC Project No 99-0584 <br /> Page 3 of 8 <br /> I concentrations as high as 6,800 µg/kg(xylene) MTBE and TBA were detected in the stock pile at <br /> concentrations up to 500 gg/kg and 970 µg/kg, respectively <br /> I2 2 2 Dissolved Petroleum Hydrocarbons <br /> TPH-g was detected in the grab ground water sample at a concentration of 37 milligram per liter <br /> (mg/1) MTBE was also detected in the grab ground water sample at a concentration of <br /> 3,200 micrograms per liter(µg/1) <br /> 23 SITE ASSESSMENT ACTIVITIES <br /> On 08 and 09 February�AGE advanced six soil bonngs to collected soil samples and for the <br /> construction of five ground water monitoring wells The borings encountered silty clay at 5 feet bsg, <br /> sand to coarse sand with gravel at between 10 feet and 15 feet bsg and between 20 and 30 feet bsg, <br /> thin, alternating clay and sand between 15 and 20 feet bsg,and clay with sand from 30 feet to 45 feet <br /> • bsg in boring SB 1 Soil cross sections AC and BD are provided as Figures 3 and 4, respectively <br /> Laboratory analysis of eighteen soil samples detected TPH-g, TPH-d and BTEX compounds in soil <br /> I sample SB 1-10, TPH-g and TPH--d were detected at concentrations of 4 mg/kg and 4 mg/kg, <br /> respectively, and BTEX compounds were detected at concentrations of 12 gg/kg, 5 µg/kg, 5 Rg/kg <br /> and 20 µg/kg, respectively In addition, total xylene was detected in sample SBI-15 at a <br /> concentration of 5 gg/kg and TPH-d was detected in sample MW-1-10 at 100 mg/kg <br /> The oxygenated fuel additive MTBE was detected in seven of the soil samples analyzed The <br /> concentration of MTBE detected in the seven soil samples ranged from 7 µg/kg (MW-1-10) to <br /> 2,720 µg/kg(SB 1-10) The highest MTBE concentration was detected from soil collected from the <br /> former dispenser area at 10 feet bsg(SB 1-10),although significant concentrations were also detected <br />' at depths of 5 feet and 15 feet bsg No MTBE was detected at 35 feet or 40 feet bsg <br /> The mass of impacted soil is minimum,adsorbed and not considered mobile,based on ground water <br /> data to date Since MTBE was the only contaminant present in ground water at or slightly above the <br /> State of California's Primary Maximum Contaminant Level,the vertical and lateral extent ofMTBE <br />' in soil was mapped on Figures 3 through 5 Volumetric calculations of MTBE concentrations over <br /> a 1900 ft' area estimated that the amount of MTBE in soil is approximately 0 44 pound (lb) <br /> (Appendix A) <br /> 1 <br /> • <br /> Advanced GeoEnvironmental,Inc <br />