Résumé
Time course transformations and fate of mercury in aquatic model ecosystems were assessed. Laboratory incubations in indoor freshwater microcosms, presenting a simple biological organization, were carried out at various spiked concentrations and from a single initial contamination of the water column. The principal results obtained evidenced different biogeochemical pathways including biotic IHg methylation and reduction and transfer to the biota. Gaseous mercury species were determined in the different microcosms and significant biological induced production of elemental mercury and dimethyl Hg was observed. The overall investigation allowed determining uptake and elimination rate constants for IHg as well as the bioaccumulation kinetics of MMHg in macrophytes and snails.