Agradecimentos: The authors thank Professor John P. Sumpter for kindly providing the recombinant Saccharomyces cerevisiae (yeast oestrogen screen). The authors are grateful to Spanish Ministry of Education and Science [CTQ2008-1710; CTQ2011-26258; Consolider-Ingenio 2010 CSD2007-00055] and the Brazilian ‘Coordenação de Aperfeiçoamento de Pessoal de Nível Superior’ CAPES [114/06] for funds received to carry out this work Ver menos

Abstract: The triazines are a group of herbicides with a wide range of uses. Atrazine is, in fact, one of the most used agricultural pesticides in the world. The terbuthylazine is applied as a substitute of atrazine in some countries of Europe since 2004, when the European Union announced a ban of atrazine because of ubiquitous water contamination. In this study, both atrazine and terbuthylazine were degraded by the ozone process to estimate the efficiency on pesticide removal in water, the intermediates formed and their potential oestrogenic activity using the yeast oestrogen screen (YES) test. Both pesticides were rapidly eliminated from the medium during ozonation (applied ozone dose 0.083 and 0.02 mmol O3 L-1, respectively). The results show that both compounds generated similar by-products from ozone degradation. Moreover, significant oestrogenic activity was detected for both atrazine and terbuthylazine intermediates, during the first minutes of ozonation. The YES assay used in this study proved to be a sensitive tool in assessing trace amounts of oestrogenic chemicals, which can represent critical issues influencing the experimental results in environmental applications Ver menos