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<br /> 23 May 2003
<br /> • AGE-NC Project No 95-0184
<br /> Page 6 of 9
<br /> and 1,900 µg/1 xylenes, only benzene and xylenes were detecteA in sample CPT3-117 at
<br /> Iconcentrations of 3 2 µg/1 and 2 1 µg/1 , respectively In addition, were detected in sample
<br /> CPT2-114 at concentrations of 370 µg11 naphthalene, 150 gg/1 n-propyl benzene, 960 µg/1
<br /> 1,2,4-tnmethylbenzene and 3 00 µg/l 1,3,5-tnmethylbenzene, only i ,2,4-tnmethylbenzene, ata
<br /> concentration of 2 1 gg/l, was detected in sample CPT3-117 V
<br /> HU12/HU13 Sample CPT2-145 was collected from HU12,samples CPT2-155 and CPT3-156 were
<br /> collected at the HU 12/HU 13 boundary TPH-g and TPH-d were detected at maximum concentrations
<br /> of 45,000 gg/l and 31,000 pg/l,respectively,in sample CPT2-145`' BTEX compounds were detected
<br /> by EPA Method 8260 at maximum concentrations of 680 µg11 benzene, 5,300 µg11 toluene,
<br /> 1,60 µg/l ethylbenzene and 7,900 gg/1 xylenes, in sample CPT2-145 In addition, the following,
<br /> �, s were detected at maximum concentrations of 3 5 gg/l 1,2-DCA in sample CPT3-156,61 µg11
<br /> �� isopropylbenzene in sample CPT2-155, and 980 pg/1 naphthalene, 390 gg/1 n-propyl benzene,
<br /> 2,500 µg/1 1,2,4-tnmethylbenzene and 730 gg/l 1,3,5-tnmethylbenzene, in sample CPT2-145
<br /> HU 14 Sample CPT3-178 was collected from HU 14 TPH-g and TPH-d were detected at
<br /> concentrations of 120 µg/l and 70 µg/1, respectively The BTEX compounds benzene and xylenes
<br /> . were detect"
<br /> A Method 8260 at concentrations of 2 0 pg/1 and 5 0 pg/l, respectively In
<br /> addition, t s n-propyl benzene, 1,2,4-tnmethylbenzene and 1,3,5-tnmethylbenzene were
<br /> detected at concentrations of 1 3 pg/l, 5 4 µg/l and 1 9 pg/l, respectively
<br /> IThe laboratory report(MAI Lab I D 83757 to 83767)QA/QC report and chain-of-custody form are
<br /> included in Appendix B'The vertical distribution of TPH-g •-Bff-EX—eamPoundf is depicted in
<br /> Figure 4, the vertical distribution of�VOCsAedepicted in
<br /> Figure 5 Analytical results of
<br /> Ithe CPT grab ground water sample is summarized in Table 1 svoci are In P` Vre"
<br /> VM
<br /> I34 SITE CONCEPTUAL MODEL L j3/0 3
<br /> The site is located in a commercial area of low topographic relief in central Stockton, on the
<br /> northeast corner of the intersection of Grant Street and Miner Avenue The site is currently operated
<br /> as Larry's Auto Repair and was formerly operated as De Rollo Mazda The property is occupied by
<br />' a single building with attached canopy and a parking area
<br /> AGE has developed a preliminary site model for the release, migration and distribution of the
<br />' contaminants in the subsurface based on the available data to date
<br /> • The subsurface stratigraphy is composed predominantly of inter-bedded fine-grained soil,
<br /> mainly clay, silty clay, clayey silt and silt, the amount of clay in subsurface soil possibly
<br />' increases off-site towards the east Inter-bedded sand layers generally appear as fine grained
<br /> . or cemented, laterally discontinuous units less than 5 feet thick, these layers may be more
<br /> i
<br /> Advanced GeoEnvironmental,Inc
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