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25 :March 2002 <br /> AGE-NC Project No 97-0326 <br />' Page 8 of 9 <br />' permeabiIity flow units with significant lateral continuity The first, third and fifth HLs, which are <br /> fine grained intervals with moderate to low permeability,are possibly leaky confining layers through <br /> which the contaminates of interest can apparently migrate vertically <br /> TPH-g and various BTEX compounds were detected In all HLTs, the highest concentrations were <br /> detected in HUi (14,000 µg/l TPH-g, 4,000 µg/1 benzene, 79 µg/1 toluene, 690 µg/1 ethylbenzene <br />' and 710 µg/1 xylenes), at a depth of 54 feet bsg In the CPT-4 location From. HU2 to HU3, TPH-g <br /> and BTEX concentrations decreased significantly,with the highest concentrations encountered near <br /> the tank-pit area (CPT-01) <br /> TPH-g and BTEX concentrations sharply increased again in HU4,the highest concentrations(6,200 <br /> µg/l TPH-g, 1,900 µg/l benzene, 65 µg/1 toluene, 29 µgrl ethylbenzene and 59 ug/1 xylenes) were <br />' detected in off-site CPT-4, at a depth of 108 feet <br />' Analytical results of ground water samples from CPT-4 and CPT-5, indicate that TPH-g and BTEX <br /> concentrations appeared to decrease from HU5 to HU6, the highest concentrations were detected in <br /> on-site CPT-5 However, MTBE, which was not detected in overlying HUs, was detected in these <br /> deeper units <br /> Petroleum-hydrocarbon compounds were detected in the deepest ground water sample collected <br />' during the CPT investigation, at a depth of 147 feet in CPT-4 (1 3 4g/1 MTBE, 8 1 ug/1 benzene, <br /> 0 78 µg/1 toluene, 0 96 µg/1 ethylbenzene and 2 1 ug/l xylenes), the vertical extent of ground water <br /> contamination is still undefined, but Is inferred to not be much deeper than the 147-feet CPT-4 <br />' sample <br /> Based on the distribution of petroleum hydrocarbons in the HUs, there is the possibility of another, <br />' offsite petroleum hydrocarbons release to the west or northwest of the K & S site which may be <br /> contributing to the hydrocarbons plume at the site <br />' S.O. RECOMMENDATIONS <br />' Based upon the CPT investigation results, AGE recommends <br />' • Continued quarterly ground wafter monitoring A quarterly ground water monitoring event <br /> occurred on 08 January 2002, the report Is in preparation <br /> • Installation of shallow and deep-screened ground water monitoring wells and vapor <br />' extraction wells based on the results of the completed and proposed CPT surveys. <br /> Advanced GeaEnviranmental,Inc <br />