DSA - Apresentações orais em encontros internacionais
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- Occupational exposure to hexavalent chromium: biomarkers of genotoxicity in human peripheral bloodPublication . Afonso, Catarina; Gomes, Bruno Costa; Louro, Henriqueta; Nogueira, Ana; Pinhal, Hermínia; Reis, Susana; Ventura, Célia; Ladeira, Carina; Ribeiro, Edna; Santonen, Tiina; Viegas, Susana; Silva, Maria JoãoThe hexavalent chromium [Cr(VI)] is a human carcinogen, which is still authorized for use in several industrial settings because it has been difficult to replace. This was the reasoning to select it as a priority chemical by the European Human Biomonitoring Initiative (HBM4EU, https://www.hbm4eu.eu/), which aims to bridge chemicals human exposure to their possible impact on health. For that purpose, not only exposure needs to be assessed but also early effect biomarkers are valuable to reflect health outcomes. The cytokinesis-block micronucleus (CBMN) assay in peripheral blood lymphocytes (PBLs) is one of the most widely used effect biomarker for measuring chromosome alterations in human cells. Since it represents a measure of both chromosome breakage and loss, an increased frequency of micronucleated cells (MNC) can reflect the effect from exposure to genotoxic agents. Moreover, there is evidence that the micronucleus (MN) frequency in PBLs is predictive of cancer risk. As part of an European multi-centre occupational study, 50 Portuguese workers exposed on a daily basis to Cr(VI) and 27 healthy controls non-exposed to Cr(VI) or other chemicals were studied. The present work intended to assess, in a more detailed manner, the early effects in a subgroup of workers (n=6) that use daily paints with Cr(VI), comparatively to that of a control group matched for age, gender and smoking habits. All participants accepted to participate by signing an informed consent previously to the blood withdrawal. An individual questionnaire to collect contextual information, e.g. personal information, lifestyle habits (smoking habits, alcohol consumption, diet), and health status was filled. Personal air samples were collected in order to assess occupational exposure to Cr(VI) soluble and insoluble compounds. Following blood culture, lymphocytes harvesting and staining using standardized methods, MNC were scored in 2000 PBL per individual. The frequencies of MNC obtained for the exposed and control groups were compared using Fisher’s exact test. Results from personal air sampling are still under evaluation. A significantly increased frequency of MNC was observed in PBLs of the 6 workers under study, comparatively to the matched controls (p < 0.001, Fisher’s exact test). These results are in line with the preliminary data obtained for the overall exposed group vs controls. The present results suggest that the frequency of micronuclei in PBLs is a reliable early effect biomarker in the case of occupational exposure to Cr(VI). Moreover, the findings also suggest a potential health risk for this group of workers. These results should promote the investment in new risk management measures and the effective application of the ones already in place, such as adequate local exhaust ventilation and a more frequent use of personal protective equipment. Additional work, considering the overall exposed group, will be developed aiming to clarify if the obtained results are due to the single exposure to Cr(VI) or to the co-exposure to several other chemicals commonly present in this type of occupational setting.