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VALUE OF MODE OF ACTION RESEARCH IN RISK ASSESSMENT
Citation:
WOLF, D. C. VALUE OF MODE OF ACTION RESEARCH IN RISK ASSESSMENT. Presented at USEPA Workshop on Research and Risk Assessment for Arsenic, Sheperdstown, WV, May 31 - June 02, 2006.
Description:
In order to develop a scientifically defensible assessment of the risk for the development of an adverse health effect including cancer after long-term exposure to xenobiotics, regulatory agencies have adopted a uniform approach. This approach includes the characterization of a toxic or carcinogenic mode of action and its biological plausibility in exposed humans. The Human Relevance Framework (HRF) and Mode-of-Action (MoA) analysis is used to assess the relevance of an increased frequency of lesions in rodents identified in toxicity and carcinogenicity studies. This approach provides a framework for assessing possible risks from exposures to pollutants or other agents in the environment. The goal is to make greater use of the scientific understanding of the process that leads to adverse health effects and cancer. The process includes analysis of all available information, identifying the key events in the processes from exposure to adverse health consequence, mode(s) of action, a description of the biological plausibility for the MoA to occur in humans, considering differential susceptibility to subpopulations, and finally characterizing the risk to humans based on the weight of scientific evidence. The MoA is considered biologically plausible in humans unless there is mechanistic evidence to refute this conclusion. Default approaches to risk assessment are only used when there are insufficient data to support a mode of action analysis and human relevancy approach.