Metal Distribution in the Environmental Compartments of Manguaba Lagoon (Alagoas State, Brazil)

Abstract

The metal concentrations in water, sediments and mollusks (Tagelus plebeius) of the Manguaba Lagoon and the influence of humic substances from water and sediments in the distribution of these metals were investigated in this work. The mean metal concentrations in water were: Mg (89.0 ± 0.11), Ca (32.0 ± 0.10), Fe (0.97 ± 0.02), Mn (0.52 ± 0.01), Zn (0.33 ± 0.10) and Pb (0.22 ± 0.02) mg L-1. The Pb concentrations were above the Brazilian legislation limit. All sediment data were below maximum limit established by the National Council for the Environment (CONAMA, Brazil) of the Ministry of the Environment, and the concentration ranges for metals were: Fe (1199-60000), Mg (339-8870), Ca (461-3838), Cr (< LOQ-39.5) and Pb (< LOQ-12.5) mg kg-1 (LOQ: limit of quantification). None of the principal contaminants (Cr, Pb and Cd) was determined in Tagelus plebeius, being a positive fact once the population nearby Manguaba Lagoon consumes large amounts of this mollusk. According to the results, the influence of humic substances in the contaminant retention is evident as they become unavailable for absorption by mollusks of Manguaba Lagoon.