Despite the acceptance of health risk assessment (RA) as a subspecialty of regulatory toxicology, it has been argued (Gordis, 1988) that "Epidemiologic methods are increasingly used to identify specific environmental and occupational hazards and to estimate the levels of risk likely to be associated with them. There (also) has been growing recognition of the need for an interdisciplinary approach to health risk assessment and, specifically, for integrating the methods and results of epidemiology, toxicology, or other research in order to derive valid estimates of health risk."

RA is considered to be more within the scope of epidemiology than of toxicology for a couple of good reasons. To extend the argument made in the last slide, it is not only because human exposure assessment is thought to be better handled by the epidemiologist than the toxicologist, but also because RA is very much a public health problem. Epidemiology is that branch of health sciences dealing primarily with community health, whereas toxicology has its focus on studying the adverse effects of chemicals on living organisms.

This limited, biased perspective might have to be corrected soon. The latest, fourth edition of Principles and Methods of Toxicology (Hayes, 2001) is among a couple of toxicology textbooks that have devoted an entire chapter on human exposure assessment (e.g., Paustenbach, 2001). And more recent textbooks of toxicology now include a section on regulatory toxicology or RA, suggesting that community environmental health problems have gradually become a topic of interest or concern to the toxicologist.