Occupational studies developed in Portugal in the scope of HBM4EU – Main results and way forward

Introduction: Within the EU human biomonitoring initiative (HBM4EU), targeted national studies on occupational settings, where exposure to chemicals could occur, were performed. These studies aimed to provide information on occupational exposure to chemicals using biomonitoring approaches to support the implementation of new risk management measures (RMM) and policy actions at national and European levels. Methods: Cross-sectional studies were performed in two occupational settings: i) a setting with plating, welding and painting activities, targeting exposure to chromium VI [Cr(VI)]; and ii) a setting dedicated to processing of electronic waste (e-waste), targeting exposure to metals. Both studies included a control group obtained from the Portuguese general population, employed in different companies with no known exposure to Cr(VI) or involvement on tasks related with recycling of e-waste. Studies enrolled 50 workers and 27 controls (chromates study) and 26 workers and 12 controls (e-waste study). Spot urine samples were collected in the beginning and the end of the work week, and concentrations of metals were determined. Protocols were submitted to Ethics Committees with the approvals being granted before recruiting the studies’ participants (companies and workers). Descriptive statistical analysis was performed as well as inferential analysis (Wilcoxon test, Mann–Whitney test, and Kruskal–Wallis test). Results: Regarding chromates study, median levels obtained for workers were 0.33 µg/g crea for Cr, in the post-shift samples. Results showed that painters presented higher levels of Cr in post-shift urine samples than the control group (p<0.05), although not presenting differences between pre-shift and post-shift urine samples (p>0.05). Platers showed higher levels of Cr in post-shift urine samples when compared to pre-shift samples (p<0.05). Welders did not present statistically significant differences between pre- and post-shift samples and in relation to control group (p>0.05). Regarding RMM, the use of respiratory protection equipment by painters was identified as a promotor of lower exposures (p<0.05). Regarding e-waste study, median levels obtained for workers were 0.21, 0.43 and 12.70 µg/g crea for cadmium (Cd), mercury (Hg) and lead (Pb), respectively, in the post-shift samples. Statistically significant differences between workers and control group were found for urinary Pb levels (p<0.05), and no significant differences were found between pre- and post-shift urine samples for Cd, Hg and Pb. Conclusions: The results obtained showed that workers are exposed to metals in these occupational settings, thus, RMM in place need to be improved. Based on the results obtained, the implementation and enforcement of new regulatory actions should be considered. The results also claim attention for the need of updating the occupational limit values as it is being discussed at European level for Cr(VI), Pb and Cd due to the related health effects [3]. The differentiated data provided by biomonitoring tools demonstrated that these should be used more often to perform exposure assessment.