Ecodynamics and bioavailability of metal contaminants in a constructed wetland within an agricultural drained catchment

•Metal removal is assessed in a wetland implemented in drained agricultural catchment.•Time-integrated tools show efficient mitigation in dissolved and particulate fractions.•Bioaccumulation based-tools reveal metal bioavailability reduced at the outlet.•Spatial-temporal monitoring supports the central role of sediments in metal trapping.•The wetland has a beneficial effect for local invertebrates in terms of exposure.