ABSTRACT
Environmental toxicology can be simplified to the understanding of only three functions. These functions are presented in Figure 2.1. First, there is the interaction of the introduced chemical which is xenobiotic with the environment. This interaction controls the amount of toxicant or dose available to the biota. Second, there is the xenobiotic interaction with its site of action. The site of action is the particular protein or other biological molecule that interacts with the toxicant. Third, there is the interaction of the xenobiotic with a site of action at the molecular level, producing effects at higher levels of biological organization. If environmental toxicologists could write appropriate functions that would describe the transfer of an effect from its interaction with a specific receptor molecule to the effects seen at the community level, it would be possible to predict accurately the effects of pollutants in the environment. We are far from a suitable understanding of these functions. The middle of the chapter introduces the critical factors for each of these. After the introduction, the three functions of the ecological systems are introduced as complex structures that have both spatial and temporal scales. Finally, the hierarchical patch dynamics paradigm is introduced as a framework that may prove useful in combining complexity and scale. Unfortunately, at this time we do not clearly understand how the impacts seen at the population and community levels are propagated from molecular interactions.
