Laserfiche WebLink
Clayton <br /> E IIRONMENTAL <br /> CO'`5ULTA,NTS <br /> borehole concentrations of VOCs during the dril ing activities as well as for field <br /> evaluation of the soil samples. <br /> 3.1.2 Decontamination <br /> In order to minimize the potential for cross con urination, decontamination <br /> procedures for the equipment used during the field work were followed. Clayton <br /> hand washed the hand auger and stainless steel tubes prior to the drilling of each <br /> borehole. The equipment was washed in an Alc noXTM detergent solution, rinsed <br /> twice in potable water, and final rinsed in deioni ed water. <br /> 3.2 FIELD WORK <br /> Clayton drilled three boreholes (BH-1, BH anc BH-3) with the hand auger. Each <br /> was borehole was drilled to a depth of 10 feet. k soil sample was collected from <br /> each borehole at a depth of 5 and 10 feet below grade. An additional soil sample was <br /> collected at 2.5 feet below grade in Borehole BH-1. The boreholes were backfilled to <br /> near grade with a cement bentonite grout, and capped with concrete. <br /> 3.3 ANALYTICAL METHODS <br /> This investigation generated soil samples for ana.ysis. Because the site was formerly <br /> occupied by a service station with possible undis losed leaking USTs, the analytical <br /> methods used for the samples from this investigation were chosen to identify typical <br /> fuel and fuel-related hydrocarbons. The laboratory analyses were performed at <br /> Clayton's laboratory facilities in Pleasanton, Cal'fomia. <br /> 3.3.1 Soil Samples <br /> The analytical methods used for the laboratory analysis of the soil samples collected <br /> during the investigation were the following: <br /> • EPA Method 8015 (modified) for gasoline <br /> • EPA Method 8020 for volatile aromatic cc mpounds (BTEX) <br /> • EPA Method 7240 for organic lead <br /> 4.0 INVESTIGATION RESULTS <br /> The subject site is located in the City of Manteca, California. Manteca is located in <br /> the Great Valley Geomorphic Province of California, in the northern portion of the <br /> San Joaquin Valley. The San Joaquin Valley, in this area, is composed of low angle <br /> to the near level alluvial plains. Deposits exposed at the surface consists primarily of <br /> 3 <br /> 46514M.RU CONFIDENTIAL AND PRIVILEGED <br />