A Risk-Based Approach for a National Assessment

The need for environmental systems modeling is growing rapidly because of the 1) combination of increasing technical scope and complexity related to questions of risk-based cause and effect and 2) need to explicitly address cost effectiveness in both the development and implementation of environmental regulations. The nature of risk assessments are evolving with their increased complexity in assessing individual sites and collection of sites, addressing regional or national regulatory needs. These assessments require the integration of existing tools and the development of new databases and models, based on a comprehensive and holistic view of the risk assessment problem. To meet these environmental regulatory needs, multiple-media-based assessments are formulated to view and assess risks from a comprehensive environmental systems perspective, crossing the boundaries of several scientific disciplines. Given the consideration and the advanced states of computer hardware and software, it is possible to design a software system that facilitates the development and integration of assessment tools (e.g., databases and models). In this paper, a risk-based approach for supporting national risk assessments is presented. This approach combines 1) databases, 2) multiple media models, combining source-term, fate and transport, exposure, and risk/hazard, and 3) sensitivity/uncertainty capabilities within a software system capable of growing within the science of risk assessment. The design and linkages of the system are discussed. This paper also provides the rationale behind the design of the framework, as there is a recognized need to develop more holistic approaches to risk assessment.