Laserfiche WebLink
1 <br /> 10 August 2002 <br />' AGE-NC Project No 98-0433 <br /> Page 3 of 4 <br />' Ground water flow direction and gradient were calculated from the June 2002 gauging data Ground <br /> water flow was Inferred to be northwesterly with a gradient of 0 001 ft/ft at the southern end of the <br />' site, rotating to a northerly flow at a gradient of 0 003 ft/ft towards the northern portion of the site <br /> (Figure 3) <br />' 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br />' TPH-g was detet din the ground water samples collected from MW-1, MW-2 and MW-6 at <br /> concentrations o1 r crograms per liter(µg/l), 330 gg/l, and 1- 6b6 gg/l, respectively TPH-d was <br /> not detected in the analyzed water samples <br /> IBTEX compounds were detected insamples MW-1 and MW-2 the maximum concenti ations were <br />' detected in sample MW-1 at 22 gg/1 benzene, 4 6 gg/l toluene, 5 0 µg/1 ethylbenzene and 6 0 gg/l <br /> xylenes &,-/ <br />'. MTBE was detected by EPA method 8260 in samples MW-1 and MW-8 at concentrations of <br /> 1,800 gg/l and 11 gg/l, respectively TAME and TBA were detected in sample MW-1 at 66gg/l and <br /> 250 µg/l, respectively <br />' Analytical results from gi ound water samples are summarized in Table 2 The laboratory report <br /> (CalTech ID 0206-118-1 to 9), quality assurance and quality control(QA/QC) and chain-of-custody <br />' are Included in Appendix B The distribution of dissolved hydrocal bons is depicted in Figure 4 <br /> 4.0. SUMMARY AND CONCLUSIONS <br /> Based upon the data collected during the June 2002 monitoring event, AGE concludes <br /> • Ground water at the site was encountered at approximately 20 53 to 22 27 feet below the <br /> casing tops The prevailing ground water flow direction varied, rotating from a generally <br />' northwest flow at the southern portion to a northerly flow in the northern portion of the site <br /> • The highest concentration of TPH-g was in the area of (monitoring well MW-1 located <br /> adjacent to the former UST area M <br /> • In general,TPH-g concentrations in ground water increased in the samples om wells MW-1 L <br /> and MW-21and BTEX concentrations decrease in samples from wells(- MW-I and IWy �i <br /> (Figure 4) since the February 2002 samplinevent^ -" 'U <br /> • Benzene was detected on in the sample from well MW-1 at a concentration above the DHS' <br /> Maximum Contaminant Level (MCL) of 1 0 gg/1 in drinking water <br /> Advanced GeoEnvironmenful,Inc <br />