Anthropogenic impact of mercury accumulation in fish from the Rio Madeira and Rio Negro rivers (Amazonia)
- 196 Downloads
Fish is an important concentrator of mono-methyl mercury and the main route to human contamination. We compared fish Hg bioaccumulation (within similar weight ranges) in two Amazonian river habitats during high-water seasons. The Rio Madeira has been greatly impacted by agriculture, alluvial gold extraction, and a hydroelectric reservoir, whereas the Rio Negro is much less affected by these human activities. The species at the top of the food web, Hoplias malabaricus (piscivorous; 80-668 ng Hg/g) and Cichla spp. (piscivorous; 42–747 ng Hg/g) showed the highest range of Hg concentrations. Nonpiscivorous species with comparable weight range, such as Potamorhina latior (detritivorous; 20–157 ng Hg/g) and Myleus torquatus (herbivorous; 2–182 ng Hg/g), had lower Hg concentrations. Triportheus elongatus (omnivorous; 5–350 ng Hg/g), with the lowest weight range, also showed a low range of Hg concentrations. Despite the Rio Madeira's higher sediment load as well as environmental impacts (deforestation, agriculture, hydroelectric reservoir, and alluvial gold mining) on natural Hg release, fish Hg bioaccumulation was no different between the two river habitats for nonpiscivorous species. In this small observational study only the species at the top of the food web (M. torquatus, Cichla spp, T. elongatus) showed higher mean Hg concentrations in the Rio Madeira than the dominantly wilderness habitat of the Rio Negro.
Index EntriesAmazonia inundation floodplain fish Hg gold mining Rio Negro Rio Madeira
Unable to display preview. Download preview PDF.
- 2.J. G. Dorea, A. C. Barbosa, J. R. Souza, and G. S. Silva, Fish-mercury bioaccumulation as a function of feeding behavior and hydrological cycles of the Rio Negro, Amazon, Comp. Biochem. Physiol. 142, 275–283 (2006).Google Scholar
- 12.AMAP, AMAP Assessment Report: Arctic Pollution Issues, Arctic Monitoring and Assessment Programme, AMAP, Oslo (1998).Google Scholar
- 17.CPM (Companhia de Pesquisa de Recursos Minerais), ServiÇo Geológico do Brasil: Perspectivas do Meio Ambiente do Brasil, CPRM, Rio de Janeiro (2002).Google Scholar
- 18.N. L. Chao, The fishery, diversity, and conservation of ornamental fishes in the Rio Negro Basin, Brazil: a review of Project Piaba (1989–99), in Conservation and Management of Ornamental Fish Resouces of the Rio Negro Basin, Amazonia, Brazil: Projeto Piaba, N. L. Chao, P. Petry, G. Prang, L. Sonneschien, and M. Tlusty, eds., EDUA, Manaus (2001).Google Scholar
- 20.M. Roulet and R. Maury-Brachet, Le mercury dans les organismes aquatiques amazoniens, in Le Mercure en Amazonie, J. P. Carmouze, M. Lucotte, and A. Boudou, eds., Institut de Recherche pour le Developpment. Collection Expertise Collegiale, Paris, pp. 204–271 (2001).Google Scholar
- 21.O. Malm, J. R. D. Guimaraes, M. B. Castro, et al., Follow-up of mercury levels in fish, human hair and urine in the Madeira and Tapajos basins, Amazon, Brazil, Water Air Soil Pollut. 97, 45–51 (1997).Google Scholar