Laserfiche WebLink
1 I <br /> II ! ^I ' � 'A r 1 t + <• _ _ r .. - - L v r f Y t t - - ' -r s_ - <br /> } I I <br /> I „ t <br /> • ` 06 June 2003 <br /> AGE-NC Project No 95-0135 <br /> Page 6 of 7 <br /> The laboratory report(CTEL Lab I D 0211-116-01 to 04 and 0211-117-01 to 09)Quality Assurance M <br />' <br /> and Quality Control (QA/QC) report and chain-of-custody form are included in Appendix B <br /> Analytical results of the CPT grab ground water samples are summarized in Table 1 Analytical <br />' results of the soil samples are summarized in Table 2 <br />' 4.0. SUMMARY/CONCLUSIONS <br /> The following conclusions were drawn from the results of this investigation <br />' • ' Silt and clay were the dominant subsurface soil types, with significant sand encountered <br /> between 90 feet bsg and total depth Groundwater was encountered at 50 feet bsg in the CPT <br />' soundings <br /> • Pore pressure dissipation tests suggest that hydraulic conductivities were typical for sand <br /> SBT at between 116 to 118 feet bsg, but the hydraulic conductivity may be too high(in the <br />' silty sand to sand BST range) for the stiff, fine-grained soil SBT at 80 feet bsg <br /> • TPH-g was detected in grab ground water samples collected from HU2 and HU3 The <br /> • highest concentrations of TPH-g were detected at the base of HU2 at approximately 80 feet <br /> bsg The lateral distribution of TPH-g (Figure 4) suggests the possibility of additional <br /> source(s) of contamination <br /> C BTEX compounds except ethylbenzene were detected in grab ground water samples from <br /> HU2 and HU3 Benzene was the most prevalent of the BTEX compounds, and is present at <br />' concentrations exceeding the DHS'Maximum Contaminant Level(MCL)for drinking water, <br /> in addition,the concentrations of benzene appear to increase with depth both on-site at CPT 1 <br /> and off-site at CPT3 and CPT4 The lateral distribution of benzene (Figure 5) suggests the <br />' possibility, of additional source(s) of contamination <br /> The vertical and lateral extent of petroleum hydrocarbon--impacted ground water has not been <br />' defined north, south and east of the site <br />' S.O. RECOMMENDATIONS <br /> 1 <br /> Based on the results of this and previous investigations;AGE recommends <br />'� • <br /> I Continued quarterly monitoring of the site <br /> I 1 <br /> I <br />' F Advanced GeoEnvnronmentai,Inc <br /> I <br /> c ` <br /> 1 1 <br />