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<br />' 07 September 2005
<br /> • AGE-NC Project No 98-0540
<br />' Page 8 of 9
<br />' • Generally, alternating Iayers of clayey soil (clayey silt, silty clay, clay, and sandy clay) and
<br /> silty and sandy soil (silt, sandy silt, silty sand, sand, and clayey sand) were encountered in
<br /> borings CPT-1,MW-4,and MW-5 to approximately 95 feet bsg In boring CPT-1,stiff,fine-
<br /> grained material and cemented sand was predominantly identified below 95 feet bsg, with
<br /> thinner (approximately 3 feet thick) layers of silt and sand encountered at approximately
<br /> 120 feet, 130 feet, and 137 feet bsg
<br /> • A total of three grab ground water samples were collected from boring CPT-1 and submitted
<br /> for laboratory analysis for the constituents listed In Section 2 12 TPH-g was detected In all
<br />' three samples at concentrations of 1,400 µg/1, 340 µg/l,and 1,400 µg/1,respectively BTEX
<br /> compounds were detected In all three samples at maximum concentrations of 180 µg/1
<br /> toluene, 57 µg/1 ethylbenzene, and 490 µg/l total xylenes 1,2-DCA was detected in sample
<br />' CPT1-135-138 at a concentration of 8 3 µg/1 EDB was detected in samples CPT 1-117-120
<br /> and CPT1-135-138 at concentrations of 3 2 µg/l and 14 µg/l, respectively
<br /> • The detected concentrations of toluene, 1,2-DCA, and EDB in grab ground water samples
<br />' collected from boring CPT-1 exceed the State of California's Maximum Contaminant Levels
<br /> (MCLS) of 150 µg/1, 0 5 µg/l, and 0 05 µg/l, respectively, for those constituents
<br /> • A total of two soil samples, collected from borings MW-4 and MW-5 at a depth of 70 feet
<br /> bsg,were analyzed for the constituents listed in Section 2 12 , no analytes were detected at
<br /> or above laboratory reporting limits in the soil samples
<br />' During the second quarter ground water monitoring event,TPH-g was detected In the ground
<br /> water samples collected from wells MW-1 and MW-3 at equivalent concentrations of
<br /> 300 µg/1 1,2-DCA was detected In the ground water samples from wells MW-1 and MW-3
<br /> through MW-5 at concentrations of 190 µg/l, 310 µg/l, 9 7 µg/l, and 9 5 µg/1, respectively
<br /> BTEX constituents were detected in well MW-1 at concentrations of 4 7 µg/1 benzene,
<br />' 4 5 µg/1 toluene, and 34 µg/1 xylenes
<br /> • The detected concentrations of 1,2-DCA and benzene In ground water samples collected
<br /> during the June 2005 ground water monitoring event exceed the State of California's MCLs
<br /> of 0 5 µg/1 and 10 µg/1, respectively, for those constituents
<br /> • No constituents of concern were detected in any of the domestic wells sampled on 14 June
<br /> 2005
<br /> • On 14 June 2005,depths to ground water ranged from 78 58 feet to 8145 feet below the tops
<br /> of the well casings Ground water elevation at the site averaged approximately 21 97 feet
<br /> below MSL, indicating an increase in ground water elevation of approximately 2 77 feet
<br /> since the last ground water monitoring event in December 2004 Ground water was Inferred
<br /> Ito be flowing toward the southwest under a hydraulic gradient of approximately 0 007 ft/ft
<br /> • With the exception of the area of well MW-2 north of the former UST location, the vertical
<br /> and lateral extents of Impacted ground water have not been fully delineated
<br /> Advanced GeoEnnronmental,Inc
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