SECTION 4 



TRENDS IN AQUATIC TOXICOLOGY IN THE UNITED STATES: 



A PERSPECTIVE 



Foster L. Mayer, Jr., Paul M. Mehrle, Jr. and Richard A. Schoettgerl 



The need for toxicology testing has increased during the 1970's. It was 

 expanded for pesticide registration; many of the same requirements for 

 pesticide registration will be required for toxic .substances approval; and 

 acute and some chronic toxicity testing are being required for ocean dumping 

 permits. Research approaches are changing from acute toxicity testing and 

 residue analysis to more complex and integrated research involving chronic 

 toxicity, clinical chemistry, and ecosystem concepts. These approaches are 

 resulting in assessments of the environmental hazard of contaminants, some- 

 times even before they enter the environment, rather than in the production 

 of acute toxicity and residue data of only limited value. Also, the inte- 

 grated approach is providing basic scientific concepts that are essential in 

 the prediction of environmental hazards. 



Developmental research is providing better interpretation and shortcuts 

 in toxicology. In ecosystem studies, scientists are determining what really 

 must be measured to assess the type and degree of pollution; biochemical 

 techniques are decreasing the time required for chronic toxicity studies; 

 and organisms other than fish (plants and invertebrates) are being recogn- 

 ized for their importance to fish and aquatic ecosystems and are being 

 tested accordingly. Recognition of the complexity of aquatic contaminant 

 residues has led to increased emphasis on the development of integrated 

 strategies for their detection and analysis. 



Research emphasis has shifted from the problems of persistent organo- 

 chlorine pesticides to the prediction of problems that may arise as mining, 

 smelting, and coal conversion are increased, new methods of sewage dis- 

 posal, petroleum and detergent use expands, and pesticides use changes in 

 forest, range, and agricultural practices. The increasing concern of indus- 

 try with environmental problems is resulting in joint industry-government 

 research, not only to assess hazards, but to further define less hazardous 

 substitutes. A new interest is emerging in metals and other inorganics. 

 Although the literature contains abundant research on organics, much of it 



^United States Fish and Wildlife Service, Columbia National Fisheries 

 Research Laboratory, Route #1, Columbia, Missouri 65201. 



44 



