Aquatic Toxicology Notes: Predicting the Fate and Effects of Aquatic and Ditchbank Herbicides1

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A&M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place , Dean Introduction The potential for a given pesticide to cause adverse effects on aquatic organisms depends on 1) its inherent toxicity to the specific organism and 2) the organism’s exposure to the compound in terms of concentration and duration (Table 1). The inherent toxicity is a specific relationship between the organism and the chemical, which cannot be changed (i.e. specific mode of action). On the other hand, exposures can be highly variable due to a variety of factors including application rates and techniques, chemical and physical properties of the chemical and environmental conditions at the time of application.