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... .ow, <br /> Site Background Information: Larry's Auto <br /> AGE-NC Project No. 95-0184 <br /> Page 7 of 8 <br /> HU6 <br /> TPH-g was detected in samples CPT1-162 and CPT1-191 at concentrations of 1,500 pg/I <br /> and 20,000 pg/l, respectively. BTEX compounds were detected in samples CPT1-162 and <br /> CPT1-191 at maximum concentrations of 89 pg/I benzene, 220 pg/I toluene, 120 pg/I <br /> ethylbenzene and 910 pg/I total xylenes, in sample CPT1-191. Fuel additives were not <br /> detected. No additional petroleum hydrocarbons were detected at or above laboratory <br /> reporting limits. <br /> ANALYTICAL RESULTS OF SOIL SAMPLES <br /> Two soil samples were collected for laboratory analysis, one at the HU1/HU2 boundary <br /> (CPT7-60) and the other in HU6 (CPT8-155). No petroleum hydrocarbons were detected <br /> at or above laboratory reporting limits. <br /> PRELIMINARY SITE CONCEPTUAL MODEL <br /> • AGE interpreted the CPT data to identify three potential hydrogeologic flow units <br /> informally identified as HU2-First Flow Unit, HU4-Second Flow Unit and HU6-Third <br /> Flow Unit . Generally, permeable to semi-permeable lithology was observed in the <br /> units that consisted of gravelly sand, fine to medium sand and silty fine sand. <br /> • AGE interpreted the CPT data to identify semi-confining/confining units informally <br /> identified as HU1, HU3 and HUS. Generally, semi-confining, silty fine sand and <br /> isolated intervals of silty clay/clayey silt was observed from HU1 and less <br /> permeable, semi-confining to confining, stiff fine grained silt and clay observed from <br /> HU3. <br /> • Petroleum hydrocarbons were detected at three of the six CPT locations: CPT-1 at <br /> the former gasoline UST area at the northwest corner of the site and CPT-5 and <br /> CPT-6 at the eastern and southeastern end of the block. The lateral extent of <br /> petroleum hydrocarbon contamination is defined to the west by soil boring CPT-8, <br /> to the north by soil boring CPT-9, and to the southwest by CPT-7; the lateral extent <br /> appears undefined to the northeast, east, southeast, and south. <br /> • The vertical extent of petroleum hydrocarbon-impacted ground water is undefined <br /> at the former gasoline UST location (CPT-1) and at the eastern end of the block on <br /> Aurora Street (CPT-5); however, it should be noted that CPT-5 was a shortened <br /> boring, encountering refusal at 115 feet bsg. Based on the November 2001 CPT <br /> investigation, the vertical extent of petroleum hydrocarbon-impacted ground water <br /> Advanced GeoEnvironmental,Inc <br />