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This study investigates the concentration of metals in the different developmental phases of the gonads of Ucides cordatus from mangrove areas of Vila do Bacuriteua on the Bragança Peninsula, Caeté-Taperaçu Marine Extractive Reserve, state of Pará, on the Brazilian Amazon coast. Elemental analysis was determined by inductively coupled plasma optical emission spectrometry (ECP-OES). Metal concentration in males ranged from Cd = 0.04 to Cu = 2.27 mg kg -1 ww in the Developing and Developed gonadal stages, respectively. In females it was from Cd = 0.11 to Cu = 8.43 mg kg -1 ww only in the Developed stage). The elements Cr and Pb, for both sexes, presented concentrations above the limits allowed by the Brazilian regulatory body and only Pb by the international agencies, revealing a higher degree of contamination of these metals in the gonads of the mangrove crabs. Increasing mangrove crab consumption amplifies the risks of metal contamination among the human population and may cause public health problems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

In order to assess the risk of exposure of human populations to dichlorodiphenyltrichloroethane (DDT) and mercury, muscles of five fish species were analysed, along with the surface sediment of 14 Iriri River sampling sites. The fish specimens were sacrificed by the spinal section, prior to sex identification, body weight determination and total length. Considering the fish specimens studied, 11% of them showed concentrations of mercury higher than the maximum established by the World Health Organization for safe human consumption. A positive correlation between fish body weight and mercury concentration was observed, besides a positive correlation between the fish size and Hg concentration. Significant differences ( P  < 0.05) were found between mean concentrations of DDT and metabolites among species of fish studied. In the Plagioscion squamossissimus species, the highest concentration of total DDT (151.4 ng/g) was found, while in Eugerres Brasilianus species, the lowest. However, the DDT levels in fish muscle of studied species are below the maximum set by FAO-Alimentarius CODEX. In the sediments, total DDT ranged from 11.58 ng/g to 48.4 ng/g, which is associated with the historical DDT use in the Amazon. According to sediment quality guidelines, these levels have a moderate toxic effect in almost all of the studied region.

The Furo of Laura is an economically important river in the Amazon estuary. Thus, in the present study, we evaluated the metal distribution (Al, Cd, Co, Cu, Cr, Fe, Ni, and Mg) in the bottom sediments of this river. The sediments were sampled at four points every 2months for a year with an Ekman-Birge sampler. After microwave acid digestion, the metal levels were determined by optical emission spectrometry with inductively coupled plasma. The particle size and organic matter content influenced the concentration of the metals. The sediments were not enriched by the analyzed metals; the estuary therefore retained the characteristics of an uncontaminated environment, thus serving as a reference environment for comparison., (Copyright © 2017 Elsevier Ltd. All rights reserved.)