Macrodéchets et déchets plastiques issus du trafic routier

The negative impact of waste dispersed in the environment has been highlighted for decades, but few field data are available in the scientific literature. Stormwater can significantly contribute to the spread and accumulation of plastic debris in the environment. However, few data exist on the rates and composition of macro litter in stormwater, including plastic debris. In order to fill this lack of knowledge, this study aims to study the occurrence, abundance and composition of macro waste from road traffic. Macrolitter, including plastic debris, were therefore collected into a retention basin draining a portion of the Nantes ring road during one year. This portion corresponds to the south part of the Cheviré bridge, which has a significant road traffic (∼90,000 veh/d on average). Macrolitter are collected and classified according to the Ospar/TG-ML classification. Over one year, 88.5 kg of debris were collected. Plastics correspond to 60% of the debris collected by mass. These plastic items are mostly fragments, cigarette butts and filters, as well as polystyrene pieces. The input sources were identified by differentiating debris deliberately dumbed (37.2%) and accidentally lost (62.8%) among the 43% of items for which this differentiation was possible. The mass of debris collected shows a linear correlation with the road traffic. These results show that road runoff can significantly contribute to macrodebris leakages, including plastics, in the receiving environments.