Plastics in the water column

There is a significant mismatch between the estimated amounts of plastics in the ocean and the expected plastic input by rivers. Most plastic transport monitoring data used for global modelling of plastic flux estimations is based on the number of items transported at the water surface. However, the amount of submerged plastic items transported in rivers is not accounted for or is based on approximations. Net measurements in rivers show that submerged plastic transport can exceed surface transport. Furthermore, existing numerical models have difficulty predicting plastic behaviour in rivers due to simplistic parametrisation, neglecting crucial factors like particle characteristics and free-surface interaction.