External exposure levels and fluoride content in the urine of workers at aluminium electrolysis

Abstract

Introduction. In the context of large-scale modernization and intensification of aluminium production, it becomes relevant to assess the actual fluoride loads and the main factors that determine the occupational exposure of workers to fluorides for health risk analysis. Materials and methods. Monitoring studies of the content of hydrofluoride and aerosols of fluoride salts in the air of electrolysis shops were carried out with traditional and modernized technologies for producing aluminium and fluorine in urine in 108 workers of the primary professions and 35 people in the control group. Determination of the concentration of fluorides was carried out by photometric methods, and fluorine in urine - by ionometric methods. Results. The total concentration of fluoride compounds in the air of the modernized shops was 1.4-2.1 times lower than the values in traditional shops. The fluoride content in the urine of workers in these workshops ranged from 0.8 to 4.7 mg/l, 1.1-6.7 times higher than the level of the control group and 1.1-2.3 times the limit value of the biological exposure index. The highest external and internal fluoride loads and associated health risks are found in workers who maintain electrolyzers and anodes. A closer, noticeable (r = 0.644) correlation was found between the content of fluoride in urine and the levels of gaseous hydrofluoride in the air, indicating its predominant effect on workers compared to other determinants (total concentration of fluorides, seniority and age). Conclusion. The studies’ results indicate a high additional informative value and reliability of biomonitoring of fluoride in urine, which, combined with analysis of air pollution with fluorides, provides a completely objective assessment of the risk of exposure to workers. The presence of high levels of hydrofluoride in the air of electrolysis shops creates a higher occupational health risk for workers.