Experimental study of mercury transfer between artificially contaminated sediment (CH3HgCl) and macrophytes (Elodea densa)

The quantification of metal transfer routes from a natural sediment enriched with methylmercury (4 mg · Hg kg⁻¹ fresh weight) to Elodea densa, shows a high mercury accumulation in the plant organs (leaves, stems and roots). The experimental approach developed shows that, in the long term (28 days), root absorption of the organic compound (direct route) represents the dominating vector of metal accumulation in the plant, the leaves being the principal organ for storage. Two mechanisms, far less important from a quantitative point of view, are superimposed in this direct transfer: contamination by the water, linked to the releasing phenomenon at the interface ‘water-sediment’, during the initial exposure phase (4 days), and inter-plant transfers resulting from decontamination processes, acting together with direct metal accumulation in the E. densa.