Publications des scientifiques de l'IRD

Maia P. D., Maurice Laurence, Tessier E., Amouroux D., Cossa D., Moreira Turcq Patricia, Etcheber H. (2018). Role of the floodplain lakes in the methylmercury distribution and exchanges with the Amazon River, Brazil. Journal of Environmental Sciences, 68, p. 24-40. ISSN 1001-0742.

Titre du document
Role of the floodplain lakes in the methylmercury distribution and exchanges with the Amazon River, Brazil
Année de publication
2018
Type de document
Article référencé dans le Web of Science WOS:000439687300003
Auteurs
Maia P. D., Maurice Laurence, Tessier E., Amouroux D., Cossa D., Moreira Turcq Patricia, Etcheber H.
Source
Journal of Environmental Sciences, 2018, 68, p. 24-40 ISSN 1001-0742
Seasonal variability of dissolved and particulate methylmercury (F-MeHg, P-MeHg) concentrations was studied in the waters of the Amazon River and its associated Curuai floodplain during hydrological year 2005-2006, to understand the MeHg exchanges between these aquatic systems. In the oxic white water lakes, with neutral pH, high F-MeHg and P-MeHg concentrations were measured during the rising water stage (0.70 +/- 0.37 pmol/L, n = 26) and flood peak (14.19 +/- 9.32 pmol/g, n = 7) respectively, when the Amazon River water discharge into the lakes was at its maximum. The lowest mean values were reported during the dry season (0.18 +/- 0.07 pmol/L F-MeHg, n = 10 and 1.35 +/- 1.24 pmol/g P-MeHg, n = 8), when water and suspended sediments were outflowing from the lakes into the River. In these lakes, the MeHg concentrations were associated to the aluminium and organic carbon/nitrogen changes. In the black water lakes, with acidic pH and reducing conditions, elevated MeHg concentrations were recorded (0.58 +/- 0.32 pmol/L F-MeHg, n = 16 and 19.82 +/- 15.13 pmol/g P-MeHg, n = 6), and correlated with the organic carbon and manganese concentrations. Elevated values of MeHg partition coefficient (4.87 < K-d < 5.08 log (L/kg) indicate that MeHg is mainly transported associated with the particulate phase. The P-MeHg enrichment detected in all lakes suggests autochthonous MeHg inputs from the sediments into the water column. The MeHg mass balance showed that the Curuai floodplain is not the source of P-MeHg for the Amazon River.
Plan de classement
Limnologie physique / Océanographie physique [032] ; Hydrologie [062] ; Géologie et formations superficielles [064]
Description Géographique
BRESIL ; AMAZONE
Localisation
Fonds IRD [F B010073671]
Identifiant IRD
fdi:010073671
Contact