BOX 8.3

The Risk Assessment Paradigm

Risk assessment consists of four elements:

  • Hazard identification—defining the hazard and nature of the harm; for example, identifying a chemical contaminant, say lead or carbon tetrachloride, and documenting its toxic effects on humans.

  • Exposure assessment—determining the concentration of a contaminating agent in the environment and estimating its rate of intake in target organisms; for example, finding the concentration of aflatoxin in peanut butter and determining the dose an “average” person would receive.

  • Dose-response assessment—quantifying the adverse effects arising from exposure to a hazardous agent based on the degree of exposure. This assessment is usually expressed mathematically as a plot showing the response in living organisms to increasing doses of the agent.

  • Risk characterization—estimating the potential impact of a hazard based on the severity of its effects and the amount of exposure.

ization can most effectively be accomplished by linked research using some model that provides pooled resources from all these agencies.


Despite the absence of existing institutional mechanisms to support research activity at the interface of earth science and public health, a base level of collaborative research exists primarily as a consequence of individual scientists establishing research partnerships and individual program managers in a variety of agencies identifying the strong merits of such research and providing support. It is also clear that there is a considerable amount of existing research activity in both the earth science and public health fields that is being carried out without knowledge or communication of potentially complementary research “across the divide.” the committee suggests that, for there to be substantial and systemic advances in interdisciplinary interaction, a formal multiagency collaboration support system needs to replace the existing ad hoc nature of collaborations. Within this context, and despite wariness about proposing yet another bureaucratic structure, the committee believes that a useful contribution would be to suggest a multitiered hierarchical management and coordination mechanism by which the relevant funding agencies could interact to promote communication and collaboration.

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