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29 June 1999 <br /> . AGE-NC Project No 97-0290 <br /> Page 6 of 7 <br /> illustrated on Figure 3 The groundwater flow direction was southerly with a gradient of 0 0012 ft/ft <br /> 3 4 ANALYTICAL RESULTS OF WATER SAMPLES <br /> TPH-g was detected at concentrations as high as 24,000 parts per billion (ppb, reported as <br /> micrograms per liter, MW2) TPH-d was detected at concentrations as high as 1,100 ppb BTEX <br /> compounds were detected at concentrations as high as 2,700 ppb, 740 ppb, 520 ppb and 1,500 ppb, <br /> respectively (MW2) <br /> Low concentrations of petroleum hydrocarbons were detected in the samples collected from MW3 <br /> and MW5 through MW8 The detected hydrocarbons in these wells are suspect, based on previous <br /> samples collected, ground water flow direction data and the estimated lateral extent of impacted <br /> ground water Hydrocarbons were not detected in the initial samples collected from MW6 and MW7 <br /> and only toluene was detected in the initial samples from MW3 and MW5 The concentrations of <br /> hydrocarbons detected in these wells was also similar The possibility of cross-contamination during <br /> sampling, laboratory contamination or laboratory error exists Continued sampling is necessary to <br />�. determine if hydrocarbons are present in these wells or if the results are anomalous <br /> DIPS was detected in the samples collected from MW2 and MW4 at concentrations of 3 3 ppb and <br /> I 2 5 ppb, respectively Tertiary butanol was detected in the samples from MW1, MW2 and MW4 at <br /> concentrations of 7 4 ppb, 12 ppb and 18 ppb, respectively Oxygenated compounds were not <br /> detected in remaining samples collected from the site during the April 1999 sampling event <br /> Analytical results of all water samples collected at the site are summarized on Tables 3 and 4 The <br /> laboratory report(AAL Batch No 99-0506-012), chain-of-custody forms and QA/QC are included <br /> in Appendix E <br /> 4.0. SUMMARY AND CONCLUSIONS <br /> Based on the data collected from the site, AGE finds <br /> - The highest concentrations of petroleum hydrocarbons in soil were again detected near the <br /> southeast portion of the site <br /> - Petroleum hydrocarbons and organic vapor were not detected during the installation of <br /> monitoring well MW8 <br /> - Groundwater was encountered in the monitoring wells at approximately 43 feet bsg and was <br /> . inferred to have a southerly flow direction during the April 1999 monitoring event <br /> Advanced GeoEmironmental,Inc <br /> I <br />