Twenty Years Before and Hence; Ecological Risk Assessment at Multiple Scales with Multiple Stressors and Multiple Endpoints

Abstract

In the 20 years since risk assessment was codified it has been applied to the management of ecological systems, first tentatively with one chemical and one receptor, to its current application at large spatial and temporal scales. The original risk assessment paradigm in the National Research Council's report Risk Assessment in the Federal Government: Managing the Process, known as the “Red Book,” was modified by the risk assessment group at Oak Ridge National Laboratory so that it could be applied to ecological systems. Even in the early 1990s, it was apparent that to be ultimately successful as a management tool, risk assessment had to be applied to populations, communities, and eventually to the ecological landscape at large scales. The risk analysis of multiple stressors, not just multiple chemicals but multiple types of agents, was also seen as a major challenge. During the late part of the 1990s and early 2000s, attempts were made to conduct risk assessments at the watershed and other comparable landscape levels. Studies on the fjord of Port Valdez, Alaska; the Clinch River in Tennessee, the Big Darby in Ohio, and Codorus Creek in Pennsylvania have attempted such risk assessments. Currently it appears possible to conduct landscape scale risk assessments, although the development of appropriate spatial statistical and uncertainty analysis methods is necessary. The future ecological risk assessment is broadening to include not only chemicals but also a wide variety of environmental stressors. These stressors include urbanization, changes in land use, fishing, and climate change. The structure of ecological risk assessment also provides a common framework allowing the multiple stakeholders, regulatory groups, and scientists to come to terms with the inherent difficulties of managing complex systems. Risk assessment has the potential of becoming the generalized quantitative tool of environmental management and decision-making at multiple scales.