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Ecohealth. 2019 Dec;16(4):743-758. doi: 10.1007/s10393-019-01451-1. Epub 2019 Nov 12.

Mercury in Populations of River Dolphins of the Amazon and Orinoco Basins.

Author information

1
Fundación Omacha, Calle 84 No. 21-64, Barrio El Polo, Bogotá, DC, Colombia. federico.mosqueraguerra@gmail.com.
2
Grupo de Ecología del Paisaje y Modelación de Ecosistemas-ECOLMOD, Departamento de Biología, Facultad de Ciencias, Universidad Nacional de Colombia, Cra 30 No. 45-03, Bogotá, DC, Colombia. federico.mosqueraguerra@gmail.com.
3
Fundación Omacha, Calle 84 No. 21-64, Barrio El Polo, Bogotá, DC, Colombia.
4
Whitley Fund for Nature, 110 Princedale Road l, London, W11 4NH, UK.
5
WWF-Brasil, CLS 114, Bloco D, Loja 35, Brasília, CEP 70.377-540, Brazil.
6
Faunagua, final Av. Max Fernández final s/n - Plazuela Chillijchi (Arocagua Norte) - Sacaba, Cochabamba, Bolivia.
7
Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, DC, Colombia.
8
Programa de Biología, Universidad del Quindío, Carrera 15 No. 12 Norte, Armenia, Quindío, Colombia.
9
Instituto Mamirauá de Desenvolvimento Sustentável, Estrada do Bexiga, 2.584 Bairro Fonte Boa, Cx. Postal 38, Tefé, AM, 69.553-225, Brazil.
10
Grupo de Ecología del Paisaje y Modelación de Ecosistemas-ECOLMOD, Departamento de Biología, Facultad de Ciencias, Universidad Nacional de Colombia, Cra 30 No. 45-03, Bogotá, DC, Colombia.

Abstract

In the Amazon and Orinoco basins, mercury has been released from artisanal and industrial gold mining since the Colonial time, as well as a result of deforestation and burning of primary forest, that release natural deposits of methyl mercury, affecting the local aquatic vertebrate fauna. This study reports the presence of mercury in river dolphins' genera Inia and Sotalia. Mercury concentrations were analysed in muscle tissue samples collected from 46 individuals at the Arauca and Orinoco Rivers (Colombia), the Amazon River (Colombia), a tributary of the Itenez River (Bolivia) and from the Tapajos River (Brazil). Ranges of total mercury (Hg) concentration in muscle tissue of the four different taxa sampled were: I. geoffrensis humboldtiana 0.003-3.99 mg kg-1 ww (n = 21, Me = 0.4), I. g. geoffrensis 0.1-2.6 mg kg-1 ww (n = 15, Me = 0.55), I. boliviensis 0.03-0.4 mg kg-1 ww (n = 8, Me = 0.1) and S. fluviatilis 0.1-0.87 mg kg-1 ww (n = 2, Me = 0.5). The highest Hg concentration in our study was obtained at the Orinoco basin, recorded from a juvenile male of I. g. humboldtiana (3.99 mg kg-1 ww). At the Amazon basin, higher concentrations of mercury were recorded in the Tapajos River (Brazil) from an adult male of I. g. geoffrensis (2.6 mg kg-1 ww) and the Amazon River from an adult female of S. fluviatilis (0.87 mg kg-1 ww). Our data support the presence of total Hg in river dolphins distributed across the evaluated basins, evidencing the role of these cetaceans as sentinel species and bioindicators of the presence of this heavy metal in natural aquatic environments.

KEYWORDS:

Amazon; Bioindication; Gold mining; Mercury contamination; Orinoco; River dolphins

PMID:
31712931
DOI:
10.1007/s10393-019-01451-1

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