First Generation of a New Science: Risk Assessment in Transition3

Abstract

The greatest challenge facing human populations today is that of extraordinary rapid change. Such a change in the society is illus trated by the increasing public awareness of environmental issues, accompanied by continuously expanding scientific investigations of chemical pollution. Our industrial civilization has developed and introduced into the various environmental media many compounds affecting human health individually and as a society. The science of toxicology is the evaluation of the effects of chemical and physical agents in various biological systems. Most chemical compounds cannot be tested in man due to their possible carcinogenic, muta genic, teratogenic, or other long-term toxic potential. Therefore, carefully designed toxicologic studies in other species, especially mammalian, are conducted to provide biological dose-response data, which can be used to predict human response. Toxicologists have the responsibility of providing accurate scientific dose- response data based on experiments employing, among others, "practical" concentrations of pollutants or toxicants. When the toxic effects are considered, the action of these agents in the atmosphere, water, and other environmental vehicles should be considered. There are always interacting events that co-exist in the environment. Multiple causality as a factor of a disease is well established but frequently overlooked. The various issues in envi ronmental health need to be tied together in order to be understood by scientists who are not intimately familiar with risk assessment procedures as they relate to the implementation of environmental laws. Much effort is needed both in the area of improved risk assessment methodology as well as in the area of toxicologic testing and validation of the theoretical approaches. The U.S. EPA is making every reasonable effort to improve its risk assessment approach.