Auxinic Herbicides and Ecotoxicological Risk for Fish Species Inhabiting the Pampas Region of South America

Abstract

The extensive use of herbicides worldwide is, at present, a potentially harmful aspect to be included in environmental health risk analyses. Formulations of auxinic herbicides containing 2,4-D, dicamba and MCPA, among others, are widely employed alone or in combination with other agrochemicals. In this sense, significant concentrations of these herbicides can be found in water bodies, inhabited by aquatic species, e.g., fish that are employed for toxicological evaluation. In the Pampas Region, different studies were performed to evaluate lethal and sublethal effects induced by the auxinic herbicides 2,4-D and dicamba, in several aquatic species. These included, Cnesterodon decemmaculatus (Cyprinodontiformes, Poeciliidae), Rhamdia quelen (Siluriformes, Heptapteridae), Poecilia vivipara (Cyprinodontiformes, Poeciliidae), Jenynsialineata (Cyprinodontiformes, Anablepidae) and Leporinus obtusidens (Characiformes, Anostomidae). The results obtained demonstrated that these compounds induce lethal and sublethal effects such as genotoxicity as well as behavioural, enzymatic, biochemical and histological alterations, to name a few. These observations highlight the feasibility of auxinic herbicides of inducing detrimental effects on these species that inhabit this highly cultivated area of South America.