The fish community of the middle Wabash River has been studied since 1973 from the standpoint of its capacity for measuring the biological impact of various kinds of point influences, such as thermal, municipal, and industrial effluents. Of particular interest has been the potential value of various community parameters as indicators of environmental quality, since individual species populations tend to vary markedly from year to year. The primary sampling method consisted of repeated direct-current electrofishing through a series of 0.5-km-long zones located strategically throughout 274 km (170 miles) of river, divided into twelve reaches. The use of cluster analysis and community indexes, including a composite index, has been of value in isolating problem areas prior to the development of lethal environmental conditions and in gaging the degree of environmental benefit resulting from improved waste treatment.

Practical and theoretical solutions to the quantitation of chemical accumulation by aquatic animals are evaluated. Laboratory studies presently rely on continuous exposure for extended periods of time to simulate field conditions. Application of the principles of pharmacokinetics permit laboratory results to be compared and indicate that mathematical models can be derived to predict contaminant accumulation under natural conditions adequately. Additional laboratory studies with large-sized and growing fish are identified as future research needs.

This symposium marks the tenth time that we have gathered as a group of professional scientists who share common goals and ideas concerning the protection of our nation's aquatic resources. This tenth symposium seems like a fitting time to reflect on our origins, our successes, and our plans for the future. To that end, several people who have been instrumental in shaping the science of aquatic toxicology and hazard (risk) assessment were invited to present their views on the growth of this science and their ideas about its future. This paper is, then, a collection of those viewpoints, which are set down in writing so that others may benefit from the experience of the authors and so that newcomers to this field may benefit by knowing about the roots of aquatic toxicology and hazard assessment. The fact that the science has persisted and grown over the past ten years is a tribute to all those who have contributed their time, energy, and intellect.

Description A pioneer attempt to assess the safety of chemicals that directly of indirectly affect water based ecosystems. 22 papers provide state-of-the-art for research approaches, new applications of old methods, new data on several pesticides and other chemicals.

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