The four key components of health risk assessment (RA) were described at some length in the first lecture. In short, risk characterization is the final step in which hazard identification and exposure information are brought together to describe and estimate the overall health risk from exposure of the toxic agent at issue.

The RA process is not only bound by social values and public concerns, but at some government levels or organizations also fragmented primarily because of limited resources and focus. It is due to this type of fragmentation and limits that toxicology and epidemiology cannot always play an important role in RA in promoting public health (PH). Accordingly, much of the discussion presented in the slides that follow is intended to delineate the areas in which epidemiology and toxicology can or cannot improve the RA process as well as PH.