Macroplastic in urban waterways: assessing storage in Berlin's Spree River

Area of Science:

• Environmental Science
• River Ecology
• Pollution Studies

Background:

• Macroplastic (MAP) pollution in rivers is a significant source of marine litter.
• Understanding MAP dynamics in urban riverbank environments is limited.
• Riverbanks play a critical role in the storage and transport of anthropogenic debris.

Purpose of the Study:

• To investigate macroplastic retention and transport dynamics on urban riverbanks.
• To identify dominant MAP categories and polymer compositions in the Spree River, Berlin.
• To analyze the influence of engineered riverbanks on MAP exchange between banks and channel.

Main Methods:

• Field sampling of macroplastics and anthropogenic material on riverbanks and in the river channel.
• Analysis of debris composition, including polymer identification.
• Spatial analysis of MAP distribution across different river compartments.

Main Results:

• Macroplastic transport on engineered urban riverbanks is predominantly unidirectional, from banks to the channel, due to embankment discontinuities.
• Polypropylene (41%) was the most common polymer, and food wrappers (35%) were the dominant debris category.
• Lateral transport from riverbanks is a significant contributor to channel macroplastic load, exceeding direct littering.

Conclusions:

• Engineered urban riverbanks significantly influence macroplastic retention and transport pathways.
• Compartment-specific understanding of MAP dynamics is essential for targeted mitigation.
• Riverbank management and cleanup strategies should consider the lateral transport of macroplastics into river channels.