Bioassays- Procedures and Results

Bioassay procedures to describe, evaluate, and predict potential hazard of toxic materials to organisms, ecosystems, and health-related aspects of polluted waters continue to receive widespread attention. However, synthesizing these diverse theoretical, methodological, and procedural entities into an integrated multidisciplinary approach to evaluate environ mental hazards of toxic substances remains difficult. Symposia proceedings pertinent to the toxic substances management in ecosystems have appeared1 and provide an overview of major problems and emerging solutions, including chapters on new bioassay protocols development, and multiple exposure toxicity paradigms. Conclusions and recommendations resulting from a toxicity testing workshop2 discussed current state-of-the-art, identified needed improvements in methodology and research priorities, and called for coordinated multidisciplinary activities regarding physico-chemical, photodegradation, biodegradation, accumulation, and ecotoxicology test protocols. A comprehensive review of test methods for ecotoxicology was prepared by the National Research Council,3 in conjunction with a companion document of working papers prepared for committee use.4 The report was critical of single-species tests to predict ecosystematic effects, and presented detailed discussions of chemical toxicity assessment, factors influencing chemical fate in terrestrial and aquatic ecosystems, relevant properties and processes, appropriate test systems and end points, and a detailed assessment strategy employing integrated use of test systems. Multispecies tests to address eco logical toxicity have been critically reviewed and evaluated,5 including methods for measuring chemical effects on aquatic and terrestrial population interactions and ecosystem properties. A primary conclusion is the need for development and standardization of tests for effects of chemicals on ecological parameters that are indicative of interspecific interactions, community dynamics, and ecosystem function