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' 17 April 2002 • AGE-NC Project No. 97-0343 ' Page 5 of 6 ' Benzene and fuel additives were not detected at or above laboratory reporting limits in any of the ground water samples.The laboratory report(MAI Lab I.D.88129 through 88131,88234 and 88235) QA/QC report and chain-of-custody form are included in Appendix B.Analytical results of the CPT grab ground water samples are summarized in Table 1. 3.4. LABORATORY RESULTS OF SOIL SAMPLE The general count of heterotrophic organisms in soil sample CPT1-31 was 12.2 X 105 (colony- forming units/gram) cfu/g and the selective count was 2.1 X 105 cfu/g, which indicate a moderate population of organisms capable of gasoline metabolism. However,the nutrient concentrations are at moderate to high levels to sustain ongoing bioremediation; nitrates (NO3), phosphate(PO4) and ammonium(NH4)were detected in the sample at concentrations of 57.2 parts per million(ppm),22 ppm and 28.38 ppm, respectively, indicating. The moisture content (MC) of the soil sample was 23%. ? y, r IMicrobiological and physicochemical analytical results are summarized on Table 2. The laboratory report and chain-of-custody form are included in Appendix C. I • ' 4.0. SUMMARY AND CONCLUSIONS Based on the findings from this investigation, AGE concludes: • Gravelly sand, sand, cemented sand and sand to silty sand were encountered at depths between 20 feet bsg and 25 feet bsg and 90 feet bsg to 95 feet bsg. Silty sand, sandy silt, silt and clay were observed at all other depths.CPT computer-generated boring logs are included in Appendix A. Geologic cross sections A-A' and B-B' were generated from CPT data collected and depict general lithology beneath the site in cross sectional views(Figures 3 and 4). • TPH-g, TPH-d, toluene, ethylbenzene and total xylenes were detected in the water sample collected from CPT-1 from unit HU2. TPH-d was detected in the water sample collected from CPT-3 from unit HUI and total xylenes were detected in the water sample collected from CPT-2 from unit HUI.Benzene was not detected in the water samples.Concentrations of toluene, ethylbenzene and total xylenes detected were below the State of California Primary Maximum Contaminant Levels(MCLs).Constituents of concern detected in ground water samples collected during the CPT investigation are depicted in cross sectional views A-A' and B-B' (Figures 5 and 6). • The vertical extent of petroleum hydrocarbon-impacted ground water is defined except at iCPT-1, where below-MCL levels of contaminants were still detected. Advanced GeoEnvironmental,Inc.