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J t n t i ly. r r 10 March 1998 AGE-NC Protect No 95-0135 Page 8 of 9 _ TPH-g was detected at a concentration of 13,000 parts per billion{ppb,reported as micrograms per i rliter)in the samples from well MW-1 A,the lower screen of well MW-I Sample MW-IB,collected from the upper screen of the well contained TPH-g at a concentration of 7,000 ppb Benzene was i p 4 detected at concentrations of 3,300 and 320 ppb in samples MW-lA and MW-1B, respectively These are the maximum benzene concentration detected at the site The maximum toluene concentration detected was 200 ppb,encountered to MW-IA The maximum r i ethylbenzene and total xylenes concentrations of 700 ppb and 1,500 ppb, respectively, were encountered in samples MW-IA and MW-2A i MTBE, TBA, ETBE and TAME were not detected in any of the water samples analyzed DIPE was detected in the water samples MW-2A, MW-2B and MW-3B at concentrations of 120, 74 and 2 7 ippb, respectively Analytical results of ground water samples are summanzed on Table 4 -Analytical Results of Ground i Water Samples -Analyzed by EPA methods 8015 and 8020 and in Table 5 -Analytical Results of Ground Water Samples - Analyzed by EPA methods 8260/8260m The laboratory report (MAI, lie Laboratory ID 81173 through 81178) and chain-of-custody are in Appendix F 5.0. SUMMARY/CONCLUSIONS The following conclusions were drawn from the results of this investigation • Hydrocarbon-impacted soil was present in the vadose zone below the former UST location, within saturated zone in the locations of the newly installed well MW-1, and distributed in the capillary zone Soil encountered at 35 feet bsg in the boring established for well MW-1 was not impacted by detectable concentrations of petroleum hydrocarbons, while soil at depths between 43 and 70 feet bsg were impacted by petroleum hydrocarbons • The impacted soil encountered between 43 and 70 feet bsg in MW-I appears to be part of a significant, undefined plume,possible associated with the former dispenser island more than I20 feet southeast of the well T •' Impacted soil encountered in the former UST cluster may extend, at depth, to the MW-1 area,but the lower hydrocarbon concentrations in the former UST cluster suggest otherwise No soil contamination was encountered in boring B2, which extended only to 35 feet bsg I • On 24 September 1997,the ground water flow direction at the site was generally toward the . northeast • The analytical data from the upper and lower screen intervals of well MW-1 indicted that the Advanced GeoEnvironnsental,Inc ^ x "