Étude des déchets plastiques et des fibres anthropiques lors d’événements transitoires: épisodes pluvieux en milieu urbain

The presence of plastic debris, whether macro-, micro- or fibres, is now recognised worldwide as a major environmental issue. Due to its high activity and dense population, the urban environment is considered a major source of plastic pollution. This article presents new data concerning plastic waste and anthropogenic fibres in rainy weather discharges downstream of a peri-urban catchment. It also proposes extrapolations of flows transferred to receiving environments at the scale of Greater Paris and the Seine basin. The abundance and composition of macroplastics, microplastics and anthropogenic fibres in the stormwater of a peri-urban residential catchment (Sucy-en-Brie, France) of Greater Paris was studied over one year (macroplastics) and 4 rainfall events (fibres and microplastics). For this site, the concentrations of macroplastics and microplastics in the rainwater are of the same order of magnitude. Extrapolating to the scale of the Paris conurbation, the estimated quantity of macroplastic debris discharged into the environment by the separate networks varies from 8 to 33 metric tons per year, while the flows of microplastics and anthropogenic fibres vary respectively from 3 to 48 tons per year and from 0.3 to 0.8 tons per year. The comparison of the various data in order to establish flows at the scale of the conurbation but also at the scale of the Seine catchment area demonstrates the complexity of tackling this pollution in a systemic manner and their use in an operational manner on a large scale is premature.