Cristina Viriato

Sao Paulo State University (UNESP), Brazil

Title: Evaluation of the potential teratogenic and toxic effect of the herbicide 2,4-D (DMA® 806) in bullfrog embryos and tadpoles (Lithobates catesbeianus)

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Biography

Cristina Viriato endeavors to apply her experience in the field of ecotoxicology, evaluating pesticides exposed to aquatic organisms. The aim of her studies is to evaluate the herbicide 2,4-D and its commercial formula, which is a widely used herbicide and one of the most used pesticide in Brazil, using bullfrog (Lithobates catesbeianus) and zebrafish (Danio rerio) as model aquatic organisms. Currently, she is doing a PhD in São Paulo State University (UNESP), where she collaborates with TOXICAM (Nucleus of Environmental Impact Assessment on Human Health) group, which performs studies regarding to toxicological tests using different types of pesticides and other substances. Her current work involves embryos and adults of zebrafish exposed to 2,4-D (DMA® 806) and its components separately.

Abstract

Pesticides are one of the causes implicated in the decline of amphibians, which are frequently used as a biological indicator of environmental health status due to their life cycle in both aquatic and terrestrial habitats. The current agricultural production systems are contaminating the southern waters, which is one of the most important surface waters of South America. In Brazil, the herbicide 2,4-D is indiscriminately used throughout the entire country and studies demonstrate a high ecological risk. The study of the herbicide 2,4-D in its commercial formula 2,4-D (DMA® 806) allows for a better knowledge of the potential teratogenic and toxic effects of this pesticide on bullfrog (Lithobates catesbeianus) embryos and tadpoles. The result of the present study contributed to more data analyses regarding to healthiness, hematology, and histopathology of tadpoles exposed for 49 days and also values of LC50-144h (Median Lethal Concentration), EC50-144h (Median Effective Concentration), MCIG (Minimum Concentration to Inhibit Growth) and TI (Teratogenic Index) for embryos exposed to this pesticide using FETAX (Frog Embryo Teratogenesis Assay Xenopus) assay. This study showed that the herbicide 2,4-D (DMA) is not acutely toxic to embryos and tadpoles of L. catesbeianus. Nevertheless, the chronic toxicity test (49 days) demonstrated physiological stress and dehydration, characterizing this pesticide as a respiratory allergen for L. catesbeianus tadpoles. More studies on 2,4-D are needed, mainly in its commercial formulas. Currently, working on the same formula and also its components separately using zebrafish (Danio rerio) as a model organism.