Do the concentrations of MTBE in ground water pose a threat to human health?
The EPA draft drinking water lifetime health advisory for MTBE is estimated to fall within the range of 20-200 g/L. The health advisory is the maximum concentration in drinking water that is not expected to cause any adverse effects over a lifetime of exposure, with a margin of safety. EPA expects to issue the final health advisory in the fall of 1995. EPA tentatively classifies MTBE as a possible human carcinogen. MTBE is also on the EPA’s Drinking Water Priority List which means it is a possible candidate for future regulation. There are no current Federal regulations that require municipalities to test for MTBE in drinking water. The water sampled by U.S. Geological Survey scientists was located near the top of the water table and is the ground water most likely to show contamination from sources at the land surface. In seven of the eight urban areas studied, the sampled ground water is the uppermost part of an aquifer used for drinking water or is possibly connected to an underlyin
