A Comparative Ecological Risk Assessment of Orimulsion and Fuel Oil #6 Spills in the Coastal Marine Environment. J. Gentile, M. Harwell, and J. Ault, Center for Marine and Environmental Analyses, University of Miami, Miami, FL
The conduct of comparative ecological risk assessments (CERA) resulting from the release of anthropogenic stressors into coastal marine environments requires theoretical and methodological innovations to integrate contaminant exposure with populations at risk over time and space scales. Consequently, predicted risks must be scaled to allow comparisons of relative ecological impacts in three physical dimensions plus time. This study was designed to compare the risks from hypothetical spills of Orimulsion and Fuel Oil #6 into the Tampa Bay ecosystem. The CERA framework used in this study integrates numerical hydrodynamic and transport-and-fate, toxicological, and biological models with extensive spatially explicit databases that describe the distributions of critical species and habitats. The presentation of the comparative ecological risks is facilitated by visualization and GIS techniques to allow realistic comparisons of toxicant exposures and their co-occurrence with key biological resources over time and across the seascape. A scaling methodology is presented that uses toxicological data as scalars for graphically representing the ecological effects associated with exposure levels for each scenario simulation. The CERA model serves as an interactive tool for assessing the relative ecological consequences of a range of potential exposure scenarios and for forecasting the longer-term productivity of critical biological resources and habitats that are key to ecosystem structure and function.