Overview
- The peer-reviewed analysis in Communications Sustainability estimates 3,000 to 4,700 tonnes of macro‑litter pass Cologne annually, equating to about 53,000 items each day.
- Using the RheinKrake device in Cologne from November 2022 to November 2023, volunteers collected 17,523 items with a total estimated mass of 1,955 kilograms.
- Plastics made up roughly 70% of items but only about 15% of weight, with more than half of objects traced to private consumers and around 28% linked to food and beverages.
- Approximately 10% of recovered objects were fireworks, illustrating strong temporal spikes that simple single‑day surveys can miss.
- Researchers note an unresolved discrepancy over the minimum item size counted (1 cm reported versus a 2.5 cm trap description), and they plan further analyses as the trap continues operating, including assessing the EU tethered‑cap rule and potential effects of higher deposits.