ARCHIVED REPORTS_XR0007454 CASE 1

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' h'q KLEINFELDER 6 CONCLUSIONS AND RECOMMENDATIONS 1 61 GROUNDWATER A transparent disposable bailer was partially submerged Into the groundwater prior to purging monitoring well MW-1 during the October 2000 and January 2001 sampling events to assess the groundwater for a potential sheen and/or floating product No product or sheen was observed in ' the groundwater samples collected during either sampling event, although a slight sheen and petroleum-like odor was noted in the purge water Monitoring well MW-1 is located approximately 5 to 10 feet south to southwest from the existing UST ' The depth to groundwater was approximately 32 58 feet bgs in October 2000 and 33 03 feet bgs in January 2001 During the initial sampling event in June 2000, the depth to groundwater was approximately 34 04 feet bgs At this time the local groundwater flow direction is unknown, although PHS/EHD has indicated that a southwestern groundwater flow direction is prevalent in surrounding areas based their experience ' The analytical results for the groundwater sample collected from MW-1 is summarized in Table Yt 2 and in the previous Section 5 TPH-D was detected in groundwater samples collected from MW-1 during the October 2000 and January 2001 sampling events at concentrations ranging from 14 4 to 18 6 mg/1 The initial groundwater sampling of MW-I in June 2000 was significantly higher at 46 8 mg/1 BTEX constituents were not detected from the groundwater samples collected from MW-1, during these two sampling events (October 2000 and January 2001) Initially, however ethylbenzene and total xylenes were detected at 4 88 µg/1 (parts per billion) and 4 17 µg/l, respectively in June 2000 Benzene and toluene have not been detected in groundwater samples since installation and groundwater sampling of MW-1 over three sampling events TPH-G, which was analyzed for the first time in January 2001 was detected in the groundwater sample collected from MW-1 at 3 3 mg/l 6.2 CONCLUSIONS Generally it appears that the concentration of TPH-D and BTEX has decreased during the October 2000 and January 2001 sampling events as compared to the initial groundwater sampling event conducted in June 2000 The concentrations of previous BTEX constituents detected in ' June 2000 were below state and federal primary Maximum Contaminant Levels (MCLS) Benzene and toluene have not been detected over three groundwater sampling events installation of MW-I in June 2000 TPH-G was analyzed for and detected for the first time in January 2001 at 3 3 mg/1 ' 20-1417-16 E03/201 IR259 Page 8 of I I Copyright 2001 Kleinfelder Inc February 28 2001