Trophic dynamics of methylmercury and trace elements in a remote Amazonian Lake

Claudio Eduardo Azevedo-Silva; Ana Carolina Pizzochero; Petrus M A Galvão; Jean P H B Ometto; Plínio B de Camargo; Antonio Azeredo; Sergio A Coelho-Souza; Krishna Das; Wanderley R Bastos; Olaf Malm; Paulo R Dorneles

doi:10.1016/j.envres.2023.116889

Trophic dynamics of methylmercury and trace elements in a remote Amazonian Lake

Environ Res. 2023 Nov 15;237(Pt 1):116889. doi: 10.1016/j.envres.2023.116889. Epub 2023 Aug 16.

Affiliations

¹ Laboratório de Radioisótopos Eduardo Penna, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro. Av. Carlos Chagas Filho S/n, Bloco G, Sala 60, Subsolo. Cidade Universitária, Ilha Do Fundão, Rio de Janeiro, RJ, Brazil.
² Instituto Nacional de Pesquisas Espaciais, Centro de Ciências Do Sistema Terrestre. Avenida Dos Astronautas, 1758, Jardim da Granja, São José Dos Campos, SP, Brazil.
³ Laboratório de Ecologia Isotópica, Centro de Energia Nuclear Na Agricultura, Universidade de São Paulo, Avenida Centenário, 303, São Dimas, Piracicaba, SP, Brazil.
⁴ Núcleo de Estudos de Saúde Coletiva, Universidade Federal Do Rio de Janeiro. Avenida Horácio Macedo, S/N. Ilha Do Fundão, Rio de Janeiro, RJ, Brazil.
⁵ Centro de Biologia Marinha, Universidade de São Paulo, (USP), Rod. Manoel Hipólito Do Rego, Km 131.5, Praia Do Cabelo Gordo, 11612-109, São Sebastião, SP, Brazil.
⁶ Freshwater and Oceanic Sciences Unit of Research (FOCUS), Laboratory of Oceanology, University of Liege, Belgium.
⁷ Laboratório de Biogeoquímica Ambiental - Universidade Federal de Rondônia. Br 364 Km 9,5. Sentido Acre, Porto Velho, RO, Brazil.
⁸ Laboratório de Radioisótopos Eduardo Penna, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro. Av. Carlos Chagas Filho S/n, Bloco G, Sala 60, Subsolo. Cidade Universitária, Ilha Do Fundão, Rio de Janeiro, RJ, Brazil; Freshwater and Oceanic Sciences Unit of Research (FOCUS), Laboratory of Oceanology, University of Liege, Belgium. Electronic address: dorneles@biof.ufrj.br.

PMID: 37595826
DOI: 10.1016/j.envres.2023.116889

Abstract

Information on pollutant trophodynamics can be crucial for public health, as contaminated food consumption may lead to deleterious effects. This study was performed in Puruzinho Lake, a remote body of water in the Brazilian Amazon from which a riparian human population obtains an important part of its animal protein intake. Samples from 92 individuals, comprising 13 species and four trophic guilds (iliophagous, planktivorous, omnivorous, and piscivorous fish) were analysed for the determination of trace elements (Fe, Cr, Mn, Ni, Zn, Ca, Sr, Cd, Sn, Tl and Pb) and methylmercury concentrations. Samples from the same individuals had already been analysed for stable isotope (SI) measurements (δ¹³C and δ¹⁵N) in a previous investigation and the SI data have been statistically treated with those generated in this study for the evaluation of trophic dynamics of contaminants. Methylmercury was the only analyte that biomagnified, presenting TMF values of 4.65 and 4.55 for total and resident ichthyofauna, respectively. Trace elements presented either trophic dilution or independence from the trophic position, constituting a behaviour that was coherent with that found in the scientific literature. The similarity between Ni behaviour through the trophic web to that of essential elements contributes to the discussion on the essentiality of this metal to fish. Considering the Non-cancer Risk Assessment, the calculated Target Hazard Quotient (THQ) values were higher than 1.0 for all analysed individuals for methylmercury, as well as for only one individual for nickel. No other analyte rendered THQ values higher than 1.0.

Keywords: Fish; Heavy metals; Migration; River-floodplain system; Trophic magnification factor; Trophic magnification slope.