Efeitos ecogenotóxicos e reprodutivos da atrazina em ambientes aquáticos: avaliação dos impactos atuais e futuros

Abstract

Atrazine is the second most widely used herbicide in Brazil due to its broad spectrum of weed control and low cost, being the cheapest herbicide found on the market. However, atrazine has a residual effect on the soil, due to the fact that it is leached during the rainy season and consequently contaminates aquatic systems. A study conducted by the Ministry of Health shows that one in every five Brazilian cities analyzed presents residual traces of atrazine in tap water. Studies suggest that atrazine can induce irreversible changes in tissue formation during embryonic development, in addition to reducing reproductive potential, endocrine disorders, and obesity. Increasing evidence shows that this herbicide may present greater toxicity in future generations. Based on this information, the scope of this work is to investigate the impacts of realistic concentrations of atrazine found in drinking water using aquatic bioindicators, in addition to exploring the interactive effects of this herbicide and factors associated with climate change. By investigating the impacts of low concentrations of atrazine (1, 2, 5, 10, 15, and 20 µg/L), we have found that the herbicide alters the reproductive cycle, physiology, and induces chromosomal aberrations in the three exposed organisms, as described in chapter 1. By associating exposure to climate change scenarios and atrazine at a concentration of 2 µg/L, we observed that the testicular function of fish could be drastically affected in future scenarios. This association synergistically compromised the different cell populations in the testicle, intensified the impacts on the expression of key genes, and impaired the production of the sexual hormones 11-KT and E2. In addition, exposure to the future climate scenario induced oxidative stress and caused complete sperm immobility, as described in chapter 2. We hope that the results found can help us better understand the role of the effects of atrazine as modulators of reproductive, physiological, and mutagenic parameters in the organisms exposed in current and predicted scenarios. This could have significant implications for future decision-making related to climate change and herbicide regulation.