Manganese and lead in children's blood and airborne particulate matter in Durban, South Africa

Despite the toxicity and widespread use of manganese (Mn) and lead (Pb) as additives to motor fuels and for other purposes, information regarding human exposure in Africa is very limited. This study investigates the environmental exposures of Mn and Pb in Durban, South Africa, a region that has utilized both metals in gasoline. Airborne metals were sampled as PM2.5 and PM10 at three sites, and blood samples were obtained from a population-based sample of 408 school children attending seven schools. In PM2.5, Mn and Pb concentrations averaged 17 ± 27 ng m− 3 and 77 ± 91 ng m− 3, respectively; Mn concentrations in PM10 were higher (49 ± 44 ng m− 3). In blood, Mn concentrations averaged 10.1 ± 3.4 μg L− 1 and 8% of children exceeded 15 μg L− 1, the normal range. Mn concentrations fit a lognormal distribution. Heavier and Indian children had elevated levels. Pb in blood averaged 5.3 ± 2.1 μg dL− 1, and 3.4% of children exceeded 10 μg dL− 1, the guideline level. Pb levels were best fit by a mixed (extreme value) distribution, and boys and children living in industrialized areas of Durban had elevated levels. Although airborne Mn and Pb concentrations were correlated, blood levels were not. A trend analysis shows dramatic decreases of Pb levels in air and children's blood in South Africa, although a sizable fraction of children still exceeds guideline levels. The study's findings suggest that while vehicle exhaust may contribute to exposures of both metals, other sources currently dominate Pb exposures.

Research Highlights► Manganese (Mn) and lead (Pb) are toxic metals emitted by vehicles and other sources. ► In Durban, South Africa, airborne concentrations of these metals were correlated. ► Mn and Pb levels in blood of Durban children were not correlated. ► In Durban children, 3% of children exceeded guideline levels for Pb. ► In Durban children, 8% of children exceeded guideline levels for Mn.