Evaluation of the status and the relationship between essential and toxic elements in the hair of occupationally exposed workers

Lead poisoning is a common disease in lead-acid battery manufacturing industries. Workers can be also exposed to various toxic elements present as contaminants or used as catalysts to enhance batteries' performances. In the present study, levels of essential and toxic elements and their relationship were assessed by analyzing scalp hair samples of 52 workers in a Pb battery manufacturing plant. The impact of some confounding factors on hair mineral contents was also investigated. For comparative purposes, nonoccupationally exposed subjects were selected as controls. All elements were determined by triple quadrupole ICP-MS. The results indicated significantly higher levels of Pb, Sb, As, and Cd in the hair of workers when compared to controls (p<0.01). The Spearman correlation test revealed significant correlations between Pb/Cr, Pb/Mn, Pb/Ni, Pb/As, Pb/Se, Pb/Sb, Hg/As, Hg/Sn, Hg/Sb, Sb/Cr, Sb/As, Sb/Se, Sb/Cd, Sb/Sn, Sn/Cr, Sn/As, Sn/Cd, Cd/As, Se/Ni, As/Cr, Ni/Cr, Ni/Mn, and Mn/Cr in the hair of workers and Pb/Cr, Pb/Mn, Pb/Ni, Pb/Cd, Mn/Ni, Mn/Cd, Cd/Ni, As/Ni, Sn/Ni, Sb/Sn, and Hg/Sn in the hair of controls. Multiple linear regression analysis revealed linear dependence including Cr = f(Pb, Ni, Sb), Mn = f(Ni, Sb), Ni = f(Mn, Cr, -Cd) (Cd was negatively correlated, <0), As = f(Sn, Sb, Hg), Se = f(Ni); Sn = f(As), Sb = f(As, Mn, -Hg, Sn, Se, -Ni) (Hg and Ni were negatively correlated), Hg = f(As, -Sb, Sn) (Sb was negatively correlated), and Pb = f(Cr). The result of this study can be very useful to explain the interactions between elements or for comparison studies when establishing reference ranges or monitoring elements in workplaces.