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SNOB Environmental Management Inc U-Hau!#704-50 ' 002-70950 03 Groundwater Monitoring Report 8113101 4.0 CONCLUSIONS 1 Blaes Environmental conducted a groundwater monitoring event at U-Haul facility #709-50 in July 2001 ' In general, groundwater levels in July 200I have dropped approximately six feet since March 2001 Based on the groundwater level measurements from the middle "B"well casings, the groundwater surface ' map for July 2001 indicated a slight flow gradient toward the south and west The highest groundwater elevation from the middle"B"well caings was measured in monitor well MW-513 1 Groundwater level measurements from the Iower"C"well casings indicated a relative groundwater low at ' monitor well MW-2 and a relative high at monitor well MW-7 Despite groundwater on the U-Haul property being relatively flat, the general flow gradient appears to be toward the north Analytical results of groundwater samples collected in July 2001 from the middle"B" and lower"C"well ' casings both indicated the presence of hydrocarbons in groundwater across the central portion of the site Results of samples collected from the middle "B" well casings revealed that the main portion of the hydrocarbon plume (with benzene concentrations greater than 10,000 pg/L) includes wells MW-213 and MW-313 Results indicated that the extent of hydrocarbons were less widespread and at lower i, concentrations from the lower"C" well casings compared to results of samples from the middle`B"well casings ' Although the analytical results of samples from the middle "B"well casings underlie the former dispenser island and former UST areas, which are likely hydrocarbon source areas, the detection of hydrocarbons in ' groundwater samples from wells MW-4 and MW-6 do not have such obvious source areas Due to the proximity of the former dispenser area, the detection of hydrocarbons in groundwater from well MWA ' are likely associated with the former dispenser area The detection of hydrocarbons in groundwater from well MW-413 support this suggestion In contrast, the detection of hydrocarbons in samples from wells ' MW-6 and MW-613 do not have local source areas and can most likely be attributed to the migration of hydrocarbons in groundwater The migration of hydrocarbons appears to be occurring at the groundwater ' interface with the detection of hydrocarbons across a wide area (MW-213, MW-3B, MW-413, and MW-613) The detection of hydrocarbons in the lower "C" well casings is less widespread and includes ' 11