Laserfiche WebLink
groundwater sample collection, the borings were backfilled with neat cement grout to the ground <br /> surface. <br /> Soil and Groundwater Sample Analysis <br /> Soil samples collected from each boring at depths of 10 and 20 feet bgs were analyzed by <br /> NEI/GTEL for total petroleum hydrocarbons as gasoline, (TPHg), benzene, toluene, <br /> ethylbenzene, and xylenes (BTEX), methyl tertiary butyl ether (MTBE), and total lead. <br /> Groundwater samples were also analyzed by NEIIGTEL for TPHg, BTEX, and MTBE. <br /> RESULTS OF INVESTIGATION <br /> Site Geolopry <br /> Native sediments encountered in soil borings SBI, SB2, and SB3 during field activities indicate <br /> that the upper 6 to 9 feet of the soil column consists primarily of clay or sand with silt. Soil from <br /> depths between 6 to 9 feet bgs and I 1 to 14 feet bgs consisted of elastic silt and silt with sand. <br /> Below I1 to 14 feet bgs, poorly graded sand was encountered to a depth of 20 feet bgs, the <br /> maximum depth explored. <br /> Soil Analytical Results <br /> Results of laboratory analyses performed on selected soil samples indicate that total lead, detected <br /> in soil samples SBI-10, SBI-20, and SB3-20, is present beneath the site at concentrations ranging <br /> from 1.7 to 5.4 milligrams per kilogram (mg/kg). The analytical results for total lead were <br /> consistent with the typical U.S. Mean and typical Bay Area concentrations in soil as presented in <br /> Summary of Typical Metals Concentrations in Soils and Surficial Materials, from U.S G.S <br /> Professional Paper 12 70for the Conterminous United States. Total lead was not detected in any <br /> of the other soil samples collected. Petroleum hydrocarbon constituents were not detected in any <br /> of the soil samples collected from borings SBI, SB2, and SB3. Analytical results of soil samples <br /> are summarized in Table 1. Laboratory data sheets and chain-of-custody documentation is <br /> presented in Attachment 3. <br /> Groundwater Analytical Results <br /> Petroleum hydrocarbon constituents were not detected in the grab groundwater samples collected <br /> from borings SB 1 and SB3. The grab groundwater sample collected from boring SB2 contained <br /> benzene and TPHg at concentrations of 0.7 parts per billion (ppb) and 60 ppb, respectively. <br /> Analytical results of groundwater samples are summarized in Table 2. Laboratory data sheets and <br /> chain-of-custody documentation are contained in Attachment 3. <br /> w-.W77391reporlslsum.doc 3 <br /> SMTH <br />