Contaminação por elementos potencialmente tóxicos em solos e poeira na região metropolitana de Belém, Amazônia oriental.

Abstract

The metropolitan region of Belém (MRB) is an important economic, cultural, and tourist hub in the Brazilian Amazon. In this region, the urbanization increasing and traffic jam may contribute to increase in levels of potentially toxic elements (PTEs) in the environment, which can promotes ecological and human health risks. The objectives of this study were to: i) determine the total, bioavailable, and bioaccessible concentrations; ii) assess the contamination levels; and iii) evaluate the risks to the environment and human health due to exposure to aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), cadmium (Cd), lead (Pb), cobalt (Co), copper (Cu), chromium (Cr), manganese (Mn), mercury (Hg), molybdenum (Mo), nickel (Ni), vanadium (V), and zinc (Zn) in soils and road dust in the MRB. Samples were collected in the densely populated areas of the five municipalities of MRB (Belém, Ananindeua, Marituba, Benevides, and Santa Bárbara). The concentrations of PTEs were quantified by inductively coupled plasma mass spectrometry (ICP-MS) and used to calculate contamination factors and environmental and human health risk indices. In both soils and dust, the average concentrations of As, Ba, Cr, Cu, Mn, Mo, Ni, Pb, and Zn were above the quality reference values established for the state of Pará. Contamination levels ranged from moderate to high for Al, As, Ba, Cr, Cu, Mn, Mo, Ni, Pb, and Zn in both matrices studied, except for Ba and Mn in soils. The potential ecological risk index was moderate for As and for the combined effect of PTEs in road dust. Potential carcinogenic risks of As and Cr were evidenced for adults and children, with the exception of Cr for adults. However, the bioavailable and bioaccessible (oral and pulmonary routes) concentrations of all PTEs were low, indicating a low current risk to the environment and human health. The results of this study can be adopted for the protection of the ecosystem and public health in the MRB.