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Objectives: The authors aimed to evaluate whether blood cadmium (B-Cd), lead (B-Pb) and mercury (B-Hg) in children differ regionally in 9 countries, and to identify factors correlating with exposure., Material and Methods: The authors performed a cross-sectional study of children aged 7-14 years, living in 2007-2008 in urban, rural, or potentially polluted ("hot spot") areas (ca. 50 children from each area, in total 1363 children) in 6 European and 3 non-European countries. The authors analyzed Cd, Pb, and total Hg in blood and collected information on potential determinants of exposure through questionnaires. Regional differences in exposure levels were assessed within each country., Results: Children living near industrial "hot-spots" had B-Cd 1.6 (95% CI: 1.4-1.9) times higher in the Czech Republic and 2.1 (95% CI:1.6-2.8) times higher in Poland, as compared to urban children in the same countries (geometric means [GM]: 0.13 μg/l and 0.15 μg/l, respectively). Correspondingly, B-Pb in the "hot spot" areas was 1.8 (95% CI: 1.6-2.1) times higher than in urban areas in Slovakia and 2.3 (95% CI: 1.9-2.7) times higher in Poland (urban GM: 19.4 μg/l and 16.3 μg/l, respectively). In China and Morocco, rural children had significantly lower B-Pb than urban ones (urban GM: 64 μg/l and 71 μg/l, respectively), suggesting urban exposure from leaded petrol, water pipes and/or coal-burning. Hg "hot spot" areas in China had B-Hg 3.1 (95% CI: 2.7-3.5) times higher, and Ecuador 1.5 (95% CI: 1.2-1.9) times higher, as compared to urban areas (urban GM: 2.45 μg/l and 3.23 μg/l, respectively). Besides industrial exposure, traffic correlated with B-Cd; male sex, environmental tobacco smoke, and offal consumption with B-Pb; and fish consumption and amalgam fillings with B-Hg. However, these correlations could only marginally explain regional differences., Conclusions: These mainly European results indicate that some children experience about doubled exposures to toxic elements just because of where they live. These exposures are unsafe, identifiable, and preventable and therefore call for preventive actions. Int J Occup Med Environ Health. 2023;36(3):349-64., (This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.)

The COPHES/DEMOCOPHES twin project was performed in 2011-2012 in 17 European countries to harmonize all steps of the human biomonitoring survey. Urinary cadmium, cotinine, phthalate metabolites, and hair mercury were measured in children (N = 120, 6-11 years) and their mothers of reproductive age, living in urban or rural areas. Cadmium in mothers' and children's urine was detected at a geometric mean (GM) concentration 0.227 and 0.109 μg/L, respectively; 95th percentile (P95) was 0.655 and 0.280 μg/L in mothers and children, respectively. No age-related, education-related, or urban versus rural differences were observed within the frame of each population group. Cadmium urinary level in mothers was about twofold compared with children. Higher levels were obtained in all smoking mothers but not in occasionally smoking or mothers and children exposed to environmental tobacco smoke (ETS). Mercury values in mothers were significantly higher in urban than in rural populations but not in children. GM and P95 for mercury in children's hair were 0.098 and 0.439 μg/g and in mothers' hair were 0.155 and 0.570 μg/g. Concentrations for mercury in the Czech samples were lower than European average. Hair mercury increased significantly with consumption of fish or seafood and with number of amalgam tooth fillings (in children). A positive association was found with family educational level. No influence of age was observed. Urinary cadmium and hair mercury levels were lower than health-based guidelines with one exception. High levels of urinary cotinine were found in the 12 smoking mothers (GM approximately 500 μg/L); lower levels in occasionally smoking mothers, N = 11 (34.5 μg/L). The mean cotinine levels in nonsmoking mothers who reported daily exposure to ETS was 10.7 μg/L. A similar mean value (10.8 μg/L) was obtained in six children who had daily exposure to ETS. In children without exposure to ETS, the mean cotinine level was 1.39 μg/L urine. Cotinine in the urine of children demonstrates limited protection of the Czech children against exposure to ETS.

Children's blood-lead concentration (B-Pb) is well studied, but little is known about cadmium (B-Cd) and mercury (B-Hg), in particular for central Europe. Such information is necessary for risk assessment and management. Therefore, we here describe and compare B-Pb, B-Cd and B-Hg in children in six European, and three non-European cities, and identify determinants of these exposures. About 50 school children (7-14 years) from each city were recruited (totally 433) in 2007-2008. Interview and questionnaire data were obtained. A blood sample was analyzed: only two laboratories with strict quality control were used. The European cities showed only minor differences for B-Cd (geometric means 0.11-0.17 μg/L) and B-Pb (14-20 μg/L), but larger for B-Hg (0.12-0.94 μg/L). Corresponding means for the non-European countries were 0.21-0.26, 32-71, and 0.3-3.2 μg/L, respectively. For B-Cd in European samples, traffic intensity close to home was a statistically significant determinant, for B-Hg fish consumption and amalgam fillings, and for B-Pb sex (boys higher). This study shows that European city children's B-Cd and B-Pb vary only little between countries; B-Hg differs considerably, due to varying tooth restoration practices and fish intake. Traffic intensity seemed to be a determinant for B-Cd. The metal concentrations were low from a risk perspective but the chosen non-European cities showed higher concentrations than the cities in Europe., (Copyright © 2011 Elsevier Ltd. All rights reserved.)