Laserfiche WebLink
_ T � <br /> PROJECT BACKGROUND <br /> 1988: Mobil Oil Corporation abandoned the former bulk storage and <br /> distribution plant. All structures were removed from the <br /> property including one underground gasoline tank and four <br /> aboveground diesel fuel storage tanks. <br /> August 1988: Following removal of the underground gasolinestorage <br /> tank, Kaprealian Engineering, Incorporated (KEI) collected and <br /> analyzed one ground water and two soil samples for fuel <br /> hydrocarbon constituents. Detectable concentrations of TPH and <br /> BTEX were present in the samples collected. <br /> November 71, 1988: KEI supervised the drilling of six onsite <br /> exploratory borings to depths ranging from 12 to 13 feet below <br /> grade (fbg) . Analyses of soil samples collected from depths of 5 <br /> and 10 feet showed detectable concentrations of TPH-D up to 2,900 <br /> parts per million (ppm) and TPH-G up to 360 ppm. Ground water <br /> was encountered between 11 and 12 fbg. <br /> February 1989: Additional soil samples were collected at the site <br /> by KEI from 12 test holes at depths of 5 and 10 fbg using a <br /> backhoe. Analyses of soil samples detected concentrations of <br /> TPH-D up to 3,600 ppm and TPH-G up to 170 ppm. Results of the <br /> investigative work revealed the presence of diesel-range <br /> contamination in the subsurface soil extending to a depth of 10 <br /> feet below grade and encompassing an area of approximately 3 ,700 <br /> cubic feet. Analytical data from test holes suggests that <br /> gasoline-range hydrocarbon-affected soil was limited to the <br /> northern portion of the site. <br /> February 1990: Mobil Oil Corporation contracted Alton Geoscience <br /> to profile the soil in situ for potential offsite disposal. The <br /> results of the soil profiling were used during excavation as an <br /> aid in segregating the soil for disposal at appropriate offsite <br /> facilities. <br /> July 9, 1990: Soil excavation was initiated. Balch Petroleum, <br /> Inc. , of Milpitas, California, was contracted by Mobil Oil to <br /> perform the excavation under the supervision of Alton Geoscience <br /> personnel. Based on the results of the in situ soil <br /> characterization, approximately 6, 100 cubic yards of soil were <br /> excavated and properly disposed of at either the Class II <br /> facility of Liquid Waste Management, Inc. , or at the Class III <br /> Durham Road Landfill. On July 23 , 1990, approximately 7, 300 <br /> cubic yards of imported clean fill was used to backfill the open <br /> excavation. <br />