Risk computation for environmental restoration activities

Abstract

Environmental restoration activities planned by the U.S. Department of Energy (DOE) and other agencies will require consideration of long-term environmental and public health risks. These restoration activities will require risk computations capabilities in support of baseline, reme- diation, and residual risk assessments. During the initial stages of problem characterization, risk screening approaches are useful; then, as more data become available, more detailed risk evaluations are appropriate. While a wide variety of models address specific site characteristics, transport media, and impact type, only a few models address the broad range of long-term public health issues encountered in environmental resto- ration activities. One such model, the Multimedia Environmental Pollutant Assessment System (MEPAS®) (© Battelle Memorial Institute, 1989, 1993), integrates radioactive and hazardous materials risk computations for major exposure routes via air, surface water, groundwater, and over- land flow transport. By considering a broad range of potential environmental issues, models such as MEPAS can be used to help prioritize potential environmental problems. An illustrative application is described involving relative risk-based evaluation of the mixed waste in underground tanks. The results provide an indication of (1) the relative importance of each of the constituents from a public-health standpoint, and (2) the sensitivity of those rankings to important input parameters.