Assessing the Ecological Risk of MTBE in Surface Water. P. Sheehan and P. Kabour, ChemRisk Division, McLaren/Hart, 1135 Atlantic Avenue, Alameda, CA
Methyl tertiarybutyl ether (MTBE) is being detected more frequently in effluent, groundwater and surface water samples. MTBE is highly soluble and relatively resistant to microbial degradation and therefore may persist in aquatic systems for moderate periods. At this time, little has been done to assess the risks posed by MTBE exposures to aquatic organisms and wildlife dependent on aquatic organism in systems contaminated by MTBE. We have taken two steps to address the issue of MTBE ecological risks. As a first step, we have evaluated the available toxicity data for aquatic species and developed distributions on no effect and low effect concentrations. As a second step, we have evaluated available toxicity data for MTBE effects on birds and mammals and have developed reference doses for selected wildlife species. These data are used to provide a preliminary characterization of the potential risk posed by MTBE in aquatic ecosystems.