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r ` ' 09 January 1998 AGE-NC Project No 96-0235 ' Page 5 of 6 , the same wells at concentrations ranging from 2 3 ppb to'1,000 ppb Toluene, ethylbenzene, and ' xylenes were detected in the same wells at concentrations ranging from 0 58 ppb to 3,300 ppb TPH- d was detected in MW-1, MW-2 and MW-3 at concentrations of 200 ppb, 2,300 ppb and 160 ppb, respectively TPH-Trio was detected in MW-2 at a,concentratlon of 320 ppb Petroleum hydrocarbons were not detected in the samples collected from MW-4 or MW-5 Tertiary butanol was detected in MW-2 at a concentration of 480 ppb Other oxygenating compounds ' were not detected at the site 1,2-Dichloroethane was detected In MW-1 and MW-2 at concentrations of 20 ppb and 80 ppb, respectively 1,2,4-Trrmethylbenzene, 1,3,5-trim ethylbenzene and n- ' propylbenzene were detected in MW-1 and MW-2 at concentrations ranging from 10 ppb to 850 ppb Chloroform was detected In MW-3 at a concentration of 2 9 ppb Analytical results of all water, samples collected at the site are sdnunanzed on Tables 2 and 3 The laboratory report (MAI Sample ' Nos 83116 through 83120), cham-o f-custody form and QA/QC are included in Appendix B R ' 50 SUMMARY AND CONCLUSIONS ' . Based on the`data r collected from the site, AGE finds 1 • The highest concentrations of hydrocarbons in ground water continue to be detected in ' samples collected from MW-2 _ , , • � r Groundwater sampled fro lr MWA and MW-2 may not be indirect communication with the ground water sampled from MW-4 and MW-5 due to completion of the former in only the ' lower clay-rich intervals –;– — • The ground water elevation at the site is higher than the tops of the screened intervals in ' monitoring Aells MW-1, MW-2 and MW-3 • The ground water flow appears to form a trough of lower ground water elevation oriented approximately through MW-1 and MW-2 This apparent trough may be related to the varying ' screen intervals of monitoring wells at the site • The apparent down-gradient extent of hydrocarbon-impacted ground water has not been ' delineated The current cross-gradient extent of impacted shallow ground water Is delineated 4 by monitoring wells MW-4 and MW-5 s 60 RECOMMENDATIONS 1 _ Based on the findings of the environmental activities recounted In this report, AGE recommends I r Advanced GeoEniironmental,Inc