Macroplastics in the water column of the Rhine : what can we learn from their characteristic? A stow net caught plastic characteristics analysis from Fall 2023 and a wet wipe degradation experiment

To design measures to combat plastic pollution in the Rhine (and its branches) as part of the Interreg project "De Rijn Verbindt / Der Rhein Verbindet", this report continues the plastic analysis of plastics from the Waal to better map the sources of plastic pollution. The macroplastics were collected from the water column in the autumn of 2023 using the stow net fishing method near Dreumel in the floodplain and near IJzendoorn in the navigation channel. Each piece of plastic was analyzed according to Rivier-OSPAR category and size, with additional information such as visual degradation category and origin. The results show that food packaging, sanitary waste, and unidentifiable soft plastic are the largest categories of the total plastic composition.
Between the two locations, there are significant differences in the size of the plastics and the plastic concentration, the most commonly found text is German, and at both locations, a large part of the plastics appears to remain in the environment for a long time, as a large part was classified in the oldest degradation category. Due to the recognizable types of plastics caught with the stow net, it is recommended to continue using this method. Additionally, it is recommended to conduct all freshwater macroplastic analyses using the Rivier-OSPAR analysis method and to express plastic concentrations in surface concentrations in future studies and reports to better compare plastic types and quantities.