Publications des scientifiques de l'IRD

Guédron Stéphane, Point David, Acha D., Bouchet S., Baya P. A., Tessier E., Monperrus M., Molina C. I., Groleau A., Chauvaud L., Thebault J., Amice E., Alanoca L., Duwig Céline, Uzu Gaëlle, Lazarro X., Bertrand Arnaud, Bertrand Sophie, Barbraud C., Delord K., Gibon François-Marie, Ibanez C., Flores M., Saavedra P. F., Ezpinoza M. E., Heredia C., Rocha F., Zepita C., Amouroux D. (2017). Mercury contamination level and speciation inventory in Lakes Titicaca and Uru-Uru (Bolivia) : current status and future trends. Environmental Pollution, 231 (1), p. 262-270. ISSN 0269-7491.

Titre du document
Mercury contamination level and speciation inventory in Lakes Titicaca and Uru-Uru (Bolivia) : current status and future trends
Année de publication
2017
Type de document
Article référencé dans le Web of Science WOS:000414881000026
Auteurs
Guédron Stéphane, Point David, Acha D., Bouchet S., Baya P. A., Tessier E., Monperrus M., Molina C. I., Groleau A., Chauvaud L., Thebault J., Amice E., Alanoca L., Duwig Céline, Uzu Gaëlle, Lazarro X., Bertrand Arnaud, Bertrand Sophie, Barbraud C., Delord K., Gibon François-Marie, Ibanez C., Flores M., Saavedra P. F., Ezpinoza M. E., Heredia C., Rocha F., Zepita C., Amouroux D.
Source
Environmental Pollution, 2017, 231 (1), p. 262-270 ISSN 0269-7491
Aquatic ecosystems of the Bolivian Altiplano (similar to 3800 m a.s.l.) are characterized by extreme hydro-climatic constrains (e.g., high UV-radiations and low oxygen) and are under the pressure of increasing anthropogenic activities, unregulated mining, agricultural and urban development. We report here a complete inventory of mercury (Hg) levels and speciation in the water column, atmosphere, sediment and key sentinel organisms (i.e., plankton, fish and birds) of two endorheic Lakes of the same watershed differing with respect to their size, eutrophication and contamination levels. Total Hg (THg) and mono-methylmercury (MMHg) concentrations in filtered water and sediment of Lake Titicaca are in the lowest range of reported levels in other large lakes worldwide. Downstream, Hg levels are 3-10 times higher in the shallow eutrophic Lake Uru-Uru than in Lake Titicaca due to high Hg inputs from the surrounding mining region. High percentages of MMHg were found in the filtered and unfiltered water rising up from <1 to similar to 50% THg from the oligoihetero-trophic Lake Titicaca to the eutrophic Lake Uru-Uru. Such high % MMHg is explained by a high in situ MMHg production in relation to the sulfate rich substrate, the low oxygen levels of the water column, and the stabilization of MMHg due to abundant ligands present in these alkaline waters. Differences in MMHg concentrations in water and sediments compartments between Lake Titicaca and Uru-Uru were found to mirror the offset in MMHg levels that also exist in their respective food webs. This suggests that in situ MMHg baseline production is likely the main factor controlling MMHg levels in fish species consumed by the local population. Finally, the increase of anthropogenic pressure in Lake Titicaca may probably enhance eutrophication processes which favor MMHg production and thus accumulation in water and biota.
Plan de classement
Limnologie physique / Océanographie physique [032] ; Ecologie, systèmes aquatiques [036] ; Pollution [038] ; Géologie et formations superficielles [064]
Description Géographique
BOLIVIE ; ANDES ; TITICACA LAC ; URU URU LAC ; ZONE TROPICALE
Localisation
Fonds IRD [F B010071349]
Identifiant IRD
fdi:010071349
Contact