Establishing a European baseline for plastic accumulation and transport in rivers

Rivers play a key role in the transport and accumulation of plastic waste in the environment. Given the durability of plastic waste and the continuation of plastic production, the accumulation of plastic in rivers is predicted to continue to increase. The goal of our research is to establish a baseline for micro- and macroplastic pollution in European rivers. To do this, we have developed a new modelling framework to simulate a European, high resolution (3 arc second), spatially probabilistic model for micro- and macroplastic transport.

While previous plastic transport models focus on quantifying plastic export to sea, we hypothesise that most plastic pollution does not reach the river outlet in the short term. This work, therefore, focuses specifically at shifting the emphasis on modelling plastic export to providing a novel outlook on the accumulation of micro- and macroplastic pollution on riverbanks and in the riverbed sediment. Our model uses the latest insights on plastic transport processes, accounting separately for both micro- and macroplastics. The model uses meteorological variables (wind and surface runoff) and land-use variables (land friction and slope) to estimate the transport of plastic from its on-land source to the river system. We use discharge, river width, riverbank friction and the presence of artificial structures, to simulate the transport of plastic in the river. An increase in the availability of plastic measurements in European rivers, allows us to provide a European specific plastic transport model for micro- and macroplastic pollution. Observed micro- and macroplastic export values, including those collected by the European RIMMEL project for floating macroplastic, were used to calibrate the model (González-Fernández et al., 2021). By accounting for the accumulated and transported plastic pollution, our model will provide a revised estimation of the spatial distribution of plastic litter in all European rivers, facilitating the implementation of tailored mitigation measures.

 

Reference:

González-Fernández, D., Cózar, A., Hanke, G., Viejo, J., Morales-Caselles, C., Bakiu, R., Barceló, D., Bessa, F., Bruge, A., & Cabrera, M. (2021). Floating macrolitter leaked from Europe into the ocean. Nature Sustainability, 4(6), 474-483.