Effects of acute and chronic exposure to the fungicide tebuconazole on tadpoles under different temperatures

• Grant number: 25/01433-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: December 31, 2025
• Field of knowledge: Biological Sciences - Zoology - Applied Zoology
• Principal Investigator: Juliane Silberschmidt Freitas
• Grantee: Rafaela Aparecida dos Reis Couto
• Host Institution: Faculdade de Ciências (FC). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil
• Associated research grant: 22/12104-4 - Fate and impacts of microplastics and pesticides in aquatic and terrestrial matrices in agricultural contexts, AP.TEM

Abstract

Brazil is one of the largest consumers of pesticides in the world, and the indiscriminate use of these products leads to ecosystem contamination, threatening sensitive organisms such as amphibians. In open systems, the toxicity of pesticides can be amplified by temperature, especially for ectothermic species, whose metabolic rates increase with warming, heightening their vulnerability to these substances. Currently, amphibians are among the groups most threatened by environmental contamination and climate change, yet few studies have focused on evaluating the effects of the interaction between these stressors on these animals. This study aims to assess the acute and chronic toxicity of a widely used agricultural fungicide, tebuconazole, on tadpoles of a Brazilian species under different temperature gradients (28°C and 34°C). First, the LC50 values for tebuconazole will be determined for the collected species at 28°C and 34°C over 96 hours, to evaluate whether there is a synergistic effect of thermal stress and tebuconazole on the lethality value for 50% of the population. Subsequently, sublethal effects will be assessed through chronic toxicity tests (15 days), using environmentally relevant concentrations of the fungicide at both temperature gradients. Genotoxicity, acetylcholinesterase (AChE) enzyme activity, swimming performance, growth and development effects, and the occurrence of abnormalities in tadpoles will be analyzed. This study will provide a better understanding of the mechanisms of action of tebuconazole under conditions common to tropical regions, contributing to the assessment of environmental risks of exposure to this fungicide for amphibians.