Resumo Introdução: trabalhadores de postos de combustíveis estão expostos às diversas substâncias químicas presentes no ambiente de trabalho, destacando-se entre elas o benzeno, devido às suas propriedades carcinogênicas. Objetivo: avaliar os danos genotóxicos relacionados à exposição ocupacional ao BTEX (benzeno, tolueno, etilbenzeno, xilenos) em trabalhadores de cinco postos de combustíveis do município do Rio de Janeiro, RJ. Metodologia: foram analisadas concentrações de BTEX no ar; atividades das enzimas catalase e glutationa S-transferase; e ensaio cometa em amostras de sangue total de 97 trabalhadores. Resultados: as concentrações de BTEX estavam dentro dos valores preconizados pela NR 15, incluindo Anexo 13-A. Entretanto, uma oscilação nos resultados de ensaio cometa foi observada entre os trabalhadores dos diferentes postos de combustíveis, principalmente em trabalhadores de postos com menores concentrações de benzeno. Discussão: esse resultado está de acordo com a literatura científica atual, que indica uma curva dose-resposta supralinear para o benzeno, observando-se em baixas concentrações um aumento não linear do risco de leucemia, provavelmente relacionado à maior metabolização do benzeno e à maior produção de seus metabólitos tóxicos nessas concentrações. Conclusão: os resultados deste estudo sugerem que a exposição ao BTEX, mesmo em baixas concentrações, contribui para o risco genotóxico à saúde humana.

No abstract

group and individuals without asbestosis, respectively. Linear regression analysis showed that 28,4% and 50,5% of comet assay results were increased by exposure to asbestos and developed asbestosis. The results of CAT and GST were not difference between the groups. These results supports the association of genotoxic damage and the onset of asbestosis by chrysotile asbestos exposure in workers of this study.Keywords: asbestos, occupational exposure, genotoxicity. IntroductionAsbestosis is a form of pneumoconiosis caused by inhaling asbestos, a generic commercial designation for a group of naturally-occurring mineral silicate fibres of the serpentine (chrysotile asbestos) and amphibole series (actinolite, amosite, anthophyllite, crocidolite and tremolite) [1]. Inhaling any kind of asbestos fibers causes the development of intense interstitial pulmonary fibrosis, which involves an inflammatory reaction, production of collagen and the formation of granuloma [2][3][4][5].Asbestosis and other diseases related to asbestos are increasing worldwide [6,7] and several studies have shown that exposure to asbestos has contributed to occupationally-related cancer. Each year, approximately 125 million people around the world are occupationally exposed to asbestos and at least 100,000 people die because of diseases related to this exposure (for example asbestos-related lung cancer, mesothelioma, or asbestosis [1]) despite the fact that "chrysotile manufacturers, governments of asbestos-producing nations, and some asbestos miners' unions contend either that their products do not cause disease or that there is insufficient evidence to reach a reliable conclusion", as stated by Pezerat (2009) [8]. Abstract: Genotoxic effects of occupational workers exposed to asbestos can be evaluated using different biomarkers as oxidative stress enzymes in conjuction with comet assay. This study assessed changes to oxidative stress enzymatic parameters and genotoxic damage in workers occupationally exposed and non-exposed to chrysotile asbestos, who attended the outpatient Clinic of the Center for Worker Health Studies and Human Ecology (CESTEH/ENSP/FIOCRUZ) in Brazil. Chest radiography and spirometry were performed to assess clinical progression of symptoms. The traditional visual score comet assay in peripheral whole blood cells was used to assess DNA damage, and oxidative stress was evaluated by measuring catalase (CAT) and glutathione S-transferase (GST) activities. Respiratory alterations were observed in 53% of workers exposed, as determined by pulmonary function and bronchodilation, and 6 workers were diagnosed with asbestosis. The comet assay was statistically significantly higher in the exposed group and individuals with asbestosis compared to the non-exposed