Mercury Levels in Fish Marketed in the Metropolitan Region of Belém, Pará, Brazil

Juliana De Souza Araujo, Marcelo de Oliveira Lima, Tommaso Giarrizzo



ercury is an environmental contaminant found in in aquatic ecosystems, derived from both manmade and natural sources. Studies of mercury contamination in fish have focused on areas with a known history of contamination, such as large rivers and their tributaries. As few data are available on the contamination of fish by heavy metals, the major urban centers in the Amazon basin have been surveyed, and in the present study, the mercury levels in the principal fish species marketed in some of the largest retailers in the city of Belém were evaluated. Samples were collected in March 2013 from the city’s principal supermarkets and street markets, either in the form of whole fish or processed portions. A sample of 10-20 g of muscle tissue was taken from each specimen for preparation and analysis in a Cold Vapor Atomic Absorption Spectrometer. Only four of the 28 species analyzed presented mercury concentrations higher than those permitted by the World Health Organization (0.5 μg.g-1). While contamination may be partly related to the feeding habits of the species, environmental variables are the principal determinants of contamination. Given this, there is a clear need for the monitoring of mercury contamination levels in fish supplies, and the careful evaluation of the supply chain, in order to minimize any major future risks to public health.


O mercúrio é um contaminante ambiental presente nos ecossistemas aquáticos tanto por motivos antrópicos como por fatores naturais. Os estudos sobre contaminação por mercúrio em peixes foram direcionados a localidades onde há um histórico de contaminação, como grandes rios e seus afluentes. Tendo em vista que nenhum estudo sobre contaminação por metais pesados em peixes foi realizado nos grandes centros urbanos amazônicos, o presente trabalho teve como objetivo avaliar os níveis de mercúrio presente nas principais espécies de peixes comercializadas nos maiores pontos de venda do município de Belém. Amostragens foram realizadas durante o mês de Março de 2013 em alguns dos principais supermercados e mercados populares de Belém, adquirindo-se o pescado em postas ou inteiro. De cada indivíduo foi coletado 10 – 20 g de músculo, que foram preparados e analisados por meio de Espectrometria de Absorção Atômica com Vapor Frio. De todas as 28 espécies analisadas, apenas quatro apresentaram concentração de mercúrio superior à permitida pela Organização Mundial da Saúde que é de 5,0 µg.g-1. Isto pode estar relacionado ao hábito alimentar das espécies, mas principalmente ao ambiente do qual elas procedem. Sendo assim, torna-se indispensável uma maior fiscalização quanto a procedência do pescado e seu monitoramento quanto aos níveis de contaminação por mercúrio, para assim prevenir qualquer dano futuro à saúde pública.


Urban Center, Amazon, Contaminated Fish, Trace Element, Fairs and Supermarkets, Trophic Levels.


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