Environmental and health impacts of potentially toxic elements in urban areas in the eastern Amazon

Abstract

In the Amazon, the expansion of urbanization and industrialization may be increasing the levels of potentially toxic elements (PTEs) in densely populated areas. The objectives of this study were to determine the total, bioavailable, and bioaccessible concentrations of PTEs, as well as to assess their environmental and human health risks in soil and road dust in the metropolitan region of Belém (MRB), eastern Amazon. For this purpose, eighty-one samples were collected in five municipalities: Belém, Ananindeua, Marituba, Benevides, and Santa Bárbara do Pará. The concentrations of PTEs were extracted via acid digestion and used to calculate contamination and risk indices. The contamination factors varied from moderate (2.7) to very high (19.5) for Al, As, Ba, Cr, Cu, Mn, Mo, Ni, Pb, and Zn in both matrices, except for Ba (1.0) and Mn (0.9) in the soil. The potential ecological risk was moderate for As (risk factor of 60.7) and the combined effect of PTEs in dust (risk index of 161.4). Potential carcinogenic risks of As and Cr were identified (hazard index > 0.0001) for adults and children, with the exception of Cr for adults. However, the bioavailable and bioaccessible (oral and pulmonary) concentrations of all PTEs indicate low current risks. The findings of this study can be used to protect the health of the environment and the inhabitants of the MRB.