IMPACTS OF FUEL OXYGENATES FROM VEHICLE EMISSIONS ON GROUNDWATER

摘要

Methyl tert-butyl ether (MTBE), ethanol, and other fuel oxygenates have been widely used since the 1970s. TheUSGS has identified MTBE as the second most common contaminant of urban aquifers in America. Previous estimates ofUSGS research suggest that MTBE concentrations in shallow groundwater could exceed 20 mug/Lbeneath high vehicular trafficareas. Along the Interstate Highway-80 (I-80) where atmospheric deposition and spills are suspected, shallow groundwater atmultiple depths was sampled with a Geoprobe~R system at ten sites throughout Nebraska. Trace concentration of fiveoxygenates in groundwater were analyzed by the solid-phase microextraction and gas chromatograph / mass spectrometry(SPME-GC/MS). Concentrations of oxygenates in shallow groundwater along I-80 were compared to those in agriculturalareas with limited atmospheric exposure to vehicle traffic and to those in surface waters in urban areas of Lincoln, Nebraska.No oxygenates were detected in the majority of water samples above the method reporting limits: 10 mug/Lfor ethanol, 3.0 mug/Lfor tert-butyl alcohol (TBA), 0.10 μg/Lfor MTBE, ethyl tert-butyl ether (ETBE), and tert-amyl ethyl ether (TAME),respectively, except for two isolated detections of MTBE and TBA in groundwater. Nonpoint sources of oxygenates fromvehicle emissions do not appear to affect shallow groundwater and surface water quality even in high traffic areas of Nebraska.