Anthropogenic Factors Both risk assessors and risk managers bring valuable perspectives to the initial planning activities for an ecological risk assessment. Risk managers charged with protecting environmental values can ensure that the risk assessment will provide information relevant to a decision. Ecological risk assessors ensure that science is effectively used to address ecological concerns. Both evaluate the potential value of conducting a risk assessment to address identified problems. Further objectives of the initial planning process are to establish management goals that are agreed upon, clearly articulated, and contain a way to measure success; determine the purpose for the risk assessment by defining the decisions to be made within the context of the management goals; and agree upon the scope, complexity, and focus of the risk assessment, including the expected output and available resources. Problem formulation, which follows these planning discussions, provides a foundation upon which the entire risk assessment depends. A brief outline of the problem formulation stage follows. A more detailed description of this stage is included in Appendix A. Problem formulation is the process by which the components of risk assessment are identified and related to each other. The components include stressors, receptors, pathways, exposures, endpoints, and adverse effects. Generally, only those receptors that are valued are considered. The pathways by which the stressor affects the receptor are varied; they can be direct or indirect. The measurements to determine impact are taken at the endpoints. An endpoint is often a valued attribute of the receptor. Because there is uncertainty in this description of a complex situation, the adverse effect can only be described as a probability. Later, there may be an iteration on the problem formulation because the information gathered may suggest a modified risk hypothesis or a new path of exposure. Considering all these components and iterations, it is not surprising that a full assessment may be very costly. An alternative is to perform the assessment in tiers, starting with a simple and inexpensive assessment and working toward a more complex and costly assessment if the situation warrants.
