Trace metals occur naturally in aquatic systems under different forms (dissolved, bound to suspended particulate matter or sediment) and they interact with organisms in these systems. This thesis aims to improve our mechanistic understanding of the distribution of trace metals in floodplains and their interactions with aquatic invertebrates. The study system was the French Rhône floodplain that harbors secondary channels with various characteristics. An interdisciplinary approach integrating tools from environmental chemistry, ecotoxicology and ecology allowed to characterize metals in different floodplain water bodies and to construct models for the quantitative link between concentrations in the environment and concentrations found in different aquatic invertebrates. Two case studies allowed to test the impact of perturbations on the patterns described above. The results have potential implications for risk assessment and for floodplain restoration.