Níveis de elementos potencialmente tóxicos na água e no sururu da Lagoa Mundaú (Alagoas, Brasil): contaminação ambiental e potencial exposição à saúde humana

Abstract

The Mundaú lagoon (Maceió, AL), besides being relevant socially, economically, and culturally, also in its surroundings, presents an intense anthropic occupation, characterized by a large population and the industrial activities presence. In this systematic environmental monitoring study carried out in the periods from 2017 to 2019, concentrations of Al, As, Bi, Cd, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Sb, Sn, V, and Zn in surface waters, and total Hg content in the bivalve Mytella charruana (sururu) were recorded, using cold vapor atomic fluorescence spectrometry (or hydride generation) (HG/CV AFS), inductively coupled plasma mass spectrometry (ICP-MS) and chronopotentiometry. In the water samples, the following elements presented concentrations above the values recommended by the National Council for the Environment (CONAMA), in g L-1: Al (24.4 - 2008), Cu (1.88 - 13.03), Fe (84.9 - 4107), Hg (< 0.0069 - 2.92), Mn (10.65 - 200), Pb (192 - 1443) and Zn (121 - 997), and therefore, the water was classified following the water pollution index (WPI), as highly impure and polluted. The Hg content in sururu, the main food in the Mundaú lagoon, varied from 0.036-0.63 mg kg-1 (dry weight) and from 0.023-0.14 mg kg-1 (wet weight). Further, the chemometric evaluation of the data based on the principal component and correlation analysis suggested a chemical-defined profile at the different sampling points. As well as, biological samples were also analyzed quantifying concentrations of Hg and Se in blood and Hg in the urine of fishermen from Mundaú lagoon. The results referring to the levels of Hg and Se (IV) in blood samples from local fishermen (n = 63) compared to a control group (n = 26), indicate statistical difference (95% confidence), with 53% of the fishermen there were values higher than Hg to the limit established by the World Health Organization. A similar profile regarding Hg was observed in the urine of the evaluated groups, which obtained a maximum concentration of 10.15 μg L-1 found for the exposed group (n = 43) and 2.65 for control (n = 17), with 9.3% of fishermen obtaining values higher than those established by legislation.