Plastics in the city: spatial and temporal variation of urban litter in a coastal town of France

Plastics are ubiquitous in the environment causing pollution recognized as a marker of the Anthropocene era. All environments are concerned including coastal and rivers ecosystems, where it has been shown that plastic waste contamination is proportional to the level of urbanization. This study investigated, for the first time in France to our knowledge, the spatial and temporal distribution of litter at the urban scale, by using debris classifications based on OSPAR (Oslo-Paris Convention 1992) vs. EPR (Extended Producer Responsibility). Two samplings involving the local population and various non-governmental associations were carried out in 2022 and 2023, in the coastal town of Banyuls-sur-Mer, France, located close to the Spanish border, with the Baillaury River running through it. The entire town as well as the port and Central Beach were sampled. A total of 30,899 debris (1,357 kg) were collected over 47.7 km of streets, riverbanks, port, and beach. Most of the debris collected in the port are tires. The amount of waste collected in the town is less than that observed on the riverbanks or at Central Beach, suggesting that the beaches and coastal areas serve as the final receptacle for mismanaged waste. Plastics represent around 70% of the collected debris and exceed alone the precautionary protection threshold defined for European Union (EU) beaches against ecological and socio-economic nuisances (i.e. 20 debris per 100 m) set by the Technical Group on Marine Litter of the Framework Directive "Strategy for the Marine Environment" (FD SMM). The data collection and standardization methods used in this study allowed direct comparison between cities, riverbanks and beaches, and with other studies, demonstrating the usefulness of participative science to help decision makers.