Browsing by Author "Afonso, Catarina"
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- Occupational exposure to Hexavalent chromium: the portuguese case within the collaborative european human biological monitoring studyPublication . Afonso, Catarina; Gomes, Bruno Costa; Louro, Henriqueta; Ladeira, Carina; Pinhal, Hermínia; Nogueira, Ana; Santos, Sílvia; Ventura, Célia; Ribeiro, Edna; Santonen, Tiina; Viegas, Susana; Silva, Maria JoãoBackground: The EU human biomonitoring initiative (HBM4EU) aims to coordinate and advance human biomonitoring across Europe. A multicenter study intending to characterize occupational exposure to hexavalent chromium [Cr(VI)], a human carcinogen, was setup in several industrial settings across Europe. In Portugal, the study was developed in one aircraft maintenance company since the substitution of Cr(VI) in this sector is not expected in the near future. Methods: The work processes that could imply exposure to Cr(VI) were characterized and exposure estimation was done. Following the company agreement and the volunteers informed consent, a survey was applied to each worker for detailed information on lifestyle, health status, etc.. Sampling for exposure and effect biomarkers analyses involved industrial hygiene samples (HIS) and biological specimens from 50 workers and 25 non-exposed individuals (controls). Biomarkers of early biological effects were studied in leukocytes from all individuals, involving the analysis of DNA damage (comet assay) and chromosome alterations (micronucleus assays); the results obtained for exposed and control individuals were statistically compared. Results and Discussion: Besides HIS results, Cr (VI) concentrations in biological samples and effect biomarkers results will be presented. The complementarity of the environmental and biological sampling, together with the sensitivity and specificity of the biomarkers used, is expected to allow exposure characterization and possible early genotoxic effects identification. Potential associations between exposure and effect biomarkers will be explored. Conclusions: An association between the levels of exposure to Cr(VI) and the early effects characterized in workers, if existent, is expected to predict potential health outcomes for Cr(VI)-exposed workers, particularly, on the long-term. All the information generated will help to support new priorities and investments regarding risk management measures to apply in this company and in the aircraft maintenance sector, in general.
- 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.
- The Usefulness of Early Effect Biomarkers in Monitoring Occupational Exposure to Hexavalent ChromiumPublication . Afonso, Catarina; Gomes, Bruno Costa; Louro, Henriqueta; Nogueira, Ana; Pinhal, Hermínia; Reis, S.; Ventura, Célia; Ladeira, Carina; Ribeiro, Edna; Santonen, Tiina; Viegas, Susana; Silva, Maria JoãoIntroduction: In the frame of the Project HBM4EU (https://www.hbm4eu.eu/) a biomonitoring study is being conducted across Europe to characterize occupational exposure to hexavalent chromium [Cr(VI)], a recognized human lung carcinogen. Herein we present the results of biomarkers of exposure and effect characterized in a group of workers from a Portuguese aircraft maintenance company, where Cr(VI) replacement is not expected in the near future. Methods: All participants signed an informed consent and responded to a questionnaire to collect contextual information. Cr(VI) exposure was assessed by the analysis of personal air samples; total Cr was measured in urine and blood samples from 50 workers and 26 controls. The effects biomarkers included the alkaline comet assay and the cytokinesis-block micronucleus assay in blood in leukocytes. Results: The concentrations of Cr in the air samples were variable, depending on the activities performed. Noteworthy, workers engaged in painting exterior surfaces with Cr(VI)-reach paints were exposed to the highest Cr(VI) levels. Results from biomonitoring confirmed the occurrence of internal exposure. Furthermore, significantly increased micronuclei frequencies (p < 0.001, Fisher’s exact test) and DNA damage levels were identified in leukocytes from workers comparatively to controls. Interestingly, among the painters showed up a group of 6 workers who were exposed to a mixture of Cr, organic solvents, silica, and other chemicals and who displayed an elevated level of micronucleated cells comparatively to matched controls. Conclusions: An association between Cr(VI) exposure and genotoxicity biomarkers was found, raising concern about a potentially increased cancer risk. Furthermore, these results suggest that the effect biomarkers selected are useful to strengthen the exposure data, in that more exposed or vulnerable groups can be more reliably detected. This is relevant to allow the prioritization of occupational hygiene and risk management measures implementation in the workplace.