Mercury in Populations of River Dolphins of the Amazon and Orinoco Basins.
Ecohealth
; 16(4): 743-758, 2019 12.
Article
in En
| MEDLINE
| ID: mdl-31712931
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.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Water Pollutants, Chemical
/
Environmental Monitoring
/
Rivers
/
Dolphins
/
Mercury
/
Mining
/
Muscles
Limits:
Animals
Country/Region as subject:
America do sul
/
Brasil
/
Colombia
Language:
En
Journal:
Ecohealth
Year:
2019
Document type:
Article
Affiliation country:
Colombia