Maurice Bourgoin Laurence auteur aut IRD Fraizy Pascal auteur aut IRD Alanoca L. auteur aut IRD Seyler Patrick auteur aut IRD Guyot Jean-Loup auteur aut IRD text conferencePaper eng text/pdf reformatted digital access Mercury contamination of waters and soils is an environmental problem of increasing concern throughout the Amazon River baxin. In order to better understand the sources of Hg in a major tributary to the Amazon, a monthly time series spanning an entire hydrological cycle has been measured for two rivers of the Upper Madeira drainage basin. At both gauging stations, we observe a hydrological control on the temporal variability of the dissolved and the total mercury (THg) concentrations: they increase in phase with increasing discharge and we observe the highest THg concentrations at the peak stage. Mercury associated with particles represents more than 90% of the TH g in high-water period, and tends to decrease only slowly with falling river stage. This suggests that weathering processes are still active during this last stage. One of the principal factors controlling the distribution of Hg in Andean waters is apparently the process of soil erosion. (Résumé d'auteur) specialized MERCURE EAU DE SURFACE CONTAMINATION POLLUTION DES EAUX CONTINENTALES COURS D'EAU CYCLE HYDROLOGIQUE BOLIVIE AMAZONIE 038POLCON International Conference on Heavy Metals in the Environment, 25., Ann Arbor (USA), 2000/08 5 multigr. Nriagu J. ed. edt IRD Ann Arbor University of Michigan 2000 https://www.documentation.ird.fr/hor/fdi:010025634 [F B010025634] https://www.documentation.ird.fr/hor/fdi:010025634 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_57-58/010025634.pdf IRD - Base Horizon / Pleins textes 2001-07-31 2021-05-20 fdi:010025634 fre