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08 August 1997 <br /> AGE-NC Project No 97-0326 <br /> Page 2 of 4 <br /> were labeled,placed in a chilled container and selected samples were transported to Alpha Analytical <br /> Laboratories,Inc (AAL)in Ukiah under chain-of-custody A total of six soil samples were analyzed <br /> for total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with method <br /> 503018015-m and aromatic hydrocarbons (benzene, toluene, ethylbenzene and xylenes, BTE&X) <br /> with methyl tertiary-butyl ether (MTBE) in accordance with EPA method 8020 <br /> All probing rods, sampling tools and sample liners used for sample collection were thoroughly rinsed <br /> with clean water after washing with a solution of Alconox between each sampling run All probings <br /> were backfilled over their entire depth with Portland cement <br /> 32 LOGGING <br /> Soil was extruded from the remaining brass sleeves and screened for the presence of organic vapor <br /> using an organic vapor meter equipped with a photo-ionization detector (PID Thermo <br /> Environmental 580A, 10 OeV, calibrated to isobutylene), and the readings were recorded on the <br /> boring logs Soil was described in accordance with the Unified Soil Classification System (see <br /> Boring Logs, Appendix A) <br /> • <br /> 40 FINDINGS <br /> 41 STRATIGRAPHY <br /> The soil type varied from silty clay to silty sand in samples collected from surface grade to 15 feet <br /> bsg Silty sand, apparently backfill material from the UST installation, was encountered in probing <br /> B3 in the 5-foot and 10-foot samples Silty sand was encountered at a depth of 20 feet bsg in each <br /> probing Silt was encountered at depths of 25 and 30 feet in probing B2, clayey fine sand was <br /> encountered at depths of 35 and 40 feet Dense silt was encountered at the terminal depth of 45 feet <br /> in probing B2 Boring logs are included in Appendix A <br /> Organic vapor was detected in probing B2 at concentrations as high as 774 parts per million (ppm) <br /> Organic vapor was also detected at a concentration of 1 ppm in the sample collected from a depth <br /> of 10 feet bsg in probing B4 <br /> 42 ANALYTICAL RESULTS OF SOIL SAMPLES <br /> TPH-g was detected in samples B2-30 and B2-40 at concentrations of 460 ppm and 1,000 ppm, <br /> . respectively Toluene, ethylbenzene and xylenes were detected in samples B2-30 and 132-40 at <br /> Advanced GcoEn%ironmental,Inc <br />