Risk assessment is still limited in its emphasis on human health. Keep in mind that environmental health, as Peter Galbraith and others noted, has to be, by statute, and should be, by science, holistic in its breadth and compass. Risk assessment has been unable to give us methods for assessing mixtures of toxic substances, which is how we are exposed to toxic substances in the real world. Risk assessment has methodologic problems that create real problems in public health because it cannot be extrapolated and used in the population, which is the dimension in which epidemiologists and public health people work. Nor does it deal with issues where dose and duration vary.
Problems exist in validating the models.
Public resistance has not abated, and all these other issues continue to reinforce the public's suspicion. We would start from a different point than the hazard-driven risk assessment model that we use for toxicology. Out of such questions, we have selected three endpoints that appear to meet the definition of being significant, having a high social cost, and not being well explained by known etiologies. The first is low birthweight, which we can look at as either a continuous or dichotomous variable. It occupies an interesting position in terms of looking at causality and is predictive of later complications in development.