What potential does the EU Single-Use Plastics Directive have for reducing plastic pollution at coastlines and riversides? An evaluation based on citizen science data

•The potential effect of the EU Single-Use Plastic (SUP) Directive was evaluated.•The study considered four sampling protocols (ca. 5,000 litter collection events)•Large scale (citizen science) datasets were invaluable to the present study.•In citizen science datasets single-use plastics make up 44 to 68% of all litter.•To reduce plastic pollution considerably, measures in addition to bans are needed. To address environmental pollution by plastic litter, the European Union adopted EU Directive 2019/904, the so called “Single-Use Plastics Directive” (SUPD), which bans several single-use plastic products and addresses additional items with measures such as extended producer responsibility and obligatory requirements for product redesign. This study assessed the potential of the SUPD to reduce litter pollution in the environment with three scenarios. The “best case” scenario assumed that all measures of the SUPD completely prevent targeted items from getting into the environment. Another scenario assumed that no measures besides bans were effective. An intermediate scenario assumed partial effectiveness of measures. Data of almost 5,000 sampling events from citizen science protocols (Plastic Pirates, International Coastal Cleanup, Marine Litter Watch) and the OSPAR protocol were used to analyse litter at riversides and coastlines in Germany and the European Union. 44 to 68% of litter items in citizen science protocols consisted of single-use plastics (cigarette butts were the most prominent items). At coastlines sampled by the OSPAR protocol, fishing gear and undefined plastics prevailed. The scenario analysis revealed that substantial litter reductions could be achieved in the “best case” scenario (upwards of 40%), while the intermediate scenario resulted in litter reductions of 13 to 25%. The marginal effect of the “only bans” scenario achieved a reduction of 2–6% in Germany and the European Union, respectively. Thus, depending on implementation and enforcement, the current SUPD can be an important first step, yet further legislative actions are needed to effectively prevent plastic waste pollution.