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EXECUTIVE SUMMARY <br /> Groundwater monitoring was performed at 8125 S EI Dorado Street (J&L Market) on <br /> April`5, 2004 After the depth to the static water level was measured, the standing water <br /> was purged and water samples were collected from the three monitoring wells The <br /> samples were analyzed for Total Petroleum Hydrocarbons in the gasoline and diesel <br /> ranges, volatile aromatic hydrocarbons (BTEX benzene, toluene, ethylbenzene, and <br /> xylene), gasoline oxygenates (methyl tertiary butyl ether, etc ), and the lead scavenger <br /> 1,2-dichloroethane <br /> Methyl tertiary butyl ether (MTBE) and 1-2 DCA concentrations remained constant at <br /> concentrations of 2-20 parts per billion in monitoring wells JLM-3 and JLM-5 The <br /> MTBE concentration in JLM-4 doubled from 13 to 26 ppb, and a second gasoline <br /> oxygenate (tertiary butanol [TBA]) was detected for the first time at 11 ppb This <br /> suggests that oxygenates have migrated toward this well since the third quarter of 2003 <br /> Total Petroleum Hydrocarbon (TPH-gasoline) and volatile aromatic concentrations <br /> (BTEX) were higher this quarter than in the previous quarter, but this may be due to <br /> analysis by a different laboratory The December 2003 samples were analyzed by <br /> Excelchem Analytical Laboratory, whereas the April 2004 samples were analyzed,by <br /> McCampbell Analytical Laboratory It is possible that these labs use slightly different <br /> analytical or interpretational procedures to obtain results with EPA method 8015, <br /> yielding slightly different concentrations <br /> The depth to groundwater on April 5 was 27 feet, which is deeper than last year at this <br /> time but shallower than in December 2003 A southwest groundwater flow direction was <br /> mapped for the first time, previously, groundwater elevation contour maps have indicated <br /> flow to the southeast The hydraulic gradient on April 5 was 0 0027 ft/ft <br /> 1 <br />