ARCHIVED REPORTS_XR0007450 CASE 1

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' k" KLEINFELDER 6 CONCLUSIONS AND RECOMMENDATIONS 1 ' 6.1 CONCLUSIONS Water levels were measured prior to each of the 2002 quarterly sampling events The depths to ' water ranged from approximately 35 to 38 feet below ground surface (bgs) In 2002 the groundwater flow direction has been consistently towards the southwest with a groundwater gradient ranging from 0 003 to 0 004 ft/ft (Table 1) No petroleum odor, floating product or sheen has been observed in perimeter monitoring wells p � gp p g MW-2, MW-3, and MW-4 A strong petroleum odor has been noted in MW-1 during the four sampling events in 2002 Approximately four inches of floating product was noted in September 2002 and a product film (<0 01 feet) was noted in December 2002 from groundwater purged from MW-1 Petroleum constituents have been pnmanly detected in MW-1 located approximately 10 feet ' down-gradient of the UST area With the exception of a trace concentration of diesel (0 076 mg/1) detected once in June 2002 from downgradient monitoring well MW-2 TPH-G, TPH-D, BTEX and five oxygenates have not been detected in penmeter monitoring wells MW-2, MW-3 and MW-4 in 2002 Oxygenates were discontinued during the fourth quarter 2002 after approval by PHS/EHD ' TPH-D was reported in groundwater from MW-1 at concentrations ranging from 13 to 350 mg/l TPH-D was detected at 27 mg/l from MW-1 during the most recent fourth quarter 2002 sampling event TPH-G was detected in MW-1 in 2002 at concentrations ranging from 1 7 to 6 4 mg/l ' TPH-G was detected in MW-1 at 1 7 mg/l during the fourth quarter of 2002 Ethylbenzene and/or total xylenes have been detected in MW-1 only during 2002 and at ' relatively low concentrations Ethylbenzene was detected in groundwater collected from MW-1 in 2002 at concentrations ranging from 1 6 to 2 1 µg/1 Total xylenes were detected at ' concentrations ranging from none detected to 1 5 µg/l The concentration of ethylbenzene found in MW-1 ranging from 1 6 to 2 1 pg/l was found to be ' well below the State and Federal Primary Maximum Contaminant Levels (MCLS) for ethylbenzene which is 700 �ig/1 The concentration of total xylenes detected in MW-1 ranging from none detected to 1 5 ug/l during 2002 was also below the State Primary MCL of 1750 ug/l ' Based on the information obtained, it is Kleinfelder's opinion that the groundwater contaminant plume is located in the vicinity of MW-1 and the existing UST and is contained within perimeter ' monitoring wells MW-2, MW-3 and MW-4 ' 18748 T02/ST03RO81 Page 10 of 12 ©2003 Kleinfelder,Inc January 23,2003 1