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1 ' 31 March 2004 AGE-NC Project No 03-1077 ' Page 6 of 7 ' Various BTEX compounds were detected in all grab groundwater samples except CPT-2-65-70,CPT-2- 94-98 and CPT-2-106-110,at maximum concentrations of 156µg/l benzene,630µg/1 ethylbenzene and 1,030 µg/l xylenes in sample CPT-4-65-70 and 103 µg/1 toluene in sample CPT-4-80-84 ' MTBE was detected only in one grab groundwater sample(CPT-3-65-69)at a concentration of 3 7µg/1 ' The vertical distribution of TPH-g concentrations in groundwater is depicted in cross sectional view A-A' (Figures 5) The laboratory report(Associated Laboratories Lab I D 120408) Quality Assurance and Quality Control(QA/QC)report and cham-of-custody form are included in Appendix C Analytical ' results of the CPT grab groundwater samples are summarized in Table 2 ' 4.0. SUMMARY AND CONCLUSIONS Based upon data collected between 18 and 21 November 2003,AGE concludes the following ' • The soil at the site consisted dominantly of clay,silt,clayey silt,and silty clay,interbedded with sand layers consisting of silty sand, fine-to medium-grained sand, and gravelly sand at depths of between 65 and 75 feet bsg, 90 and 100 feet bsg,and 110 and 115 feet bsg The thickest fine- grained interval within the sand layers was encountered at between 75 and 95 feet bsg • TPH-g, BTEX compounds and MTBE were detected in soil underlying the southwest portion of the site The highest TPH-g concentrations ranged between 408 mg/kg and 9,110 mg/kg and were detected at depths of between 40 and 100 feet bsg in CPT-4 The highest BTEX concentrations were reported in samples collected at depths of between 60 and 80 feet bsg in I CPT-4 MTBE was detected in only three samples, at a maximum concentration of 72 µg/kg TPH-g,BTEX and MTBE concentrations appear to decrease laterally and may not extend much beyond CPT-2 towards the west and CPT-3 towards the southeast • The vertical extent of TPH-g,benzene,and MTBE in soil do not appear to exceed 100 feet bsg, which indicates that the fine-grained interval at between 75 and 90 feet bsg does retard the ' vertical migration of contaminants,however, assuming no vertical cross-contamination during the sampling procedures, low concentrations of the remaining BTEX compounds toluene, ethylbenzene and/or xylenes were present to total depth in borings CPT-3 (120 feet bsg) and I CPT-4 (112 feet bsg) • TPH-g was detected in all groundwater samples except sample CPT-2-94-98 at concentrations ranging from 15,200 µg/1 at the water table to as high as 414 µg/1 at total depth The I anomalously higher concentration (414 µg/1) of TPH-g at 110 feet bsg in CPT2, located on Wilson Way west of the site, may indicate additional off-site source(s) for the deeper, hydrocarbon-impacted groundwater I Advanced GeoEnvironmental,Inc I