Introduction: the comparative approach to mechanisms of pollutant toxicity

The broad field of comparative pharmacology has as a goal "to take advantage of the diversity of form and function [of all animals] to increase our knowledge of general principles" of drug or xenobiotic interactions with the living organism (1). Our current perspective on the comparative approach is derived largely from the seminal conference on comparative pharmacology held in 1967 under the joint auspices of several NIH Institutes (2). Indeed, it is through the support of one of the organizers of the 1967 meeting, David P. Rall, the Director of the National Institute of Environmental Health Sciences, that we have had the opportunity to meet and summarize progress in this area. The goals of the present conference are to examine the current use of the comparative approach as a tool to assess the impact of xenobiotic pollution on the aquatic environment and identify those general principles that govern the interactions of environmental chemicals with aquatic organisms. We approach these goals primarily from a biochemical-physiological perspective. However, we have also tried to stress the importance of correlating detailed cellular and organ effects with intact animal responses. As a starting point, Malins et al. have used their studies in Puget Sound to document the staggering array ofchemicals found in the aquatic environment. Their work also clearly demonstrates that these chemicals, even those primarily associated with the sediments, are bioavailable and that exposure may cause readily demonstrable pathologies. Guarino describes the current state of aquatic toxicology and its roots in classical mammalian pharmacology and toxicology. He makes a case for thorough pharmacokinetic studies in aquatic species as a prerequisite to use of their unique advantages for identification of sites and mechanisms of xenobiotic toxicity. After these two largely introductory presentations, focus shifts to a more detailed look at several systems in which anatomical or physiological specializations of aquatic organisms lend themselves to study of the interactions between foreign chemicals and organ or cell