Storm Response of Fluvial Sedimentary Microplastics

Area of Science:

• Environmental Science
• Hydrology
• Ecotoxicology

Background:

• Rivers are major pathways for microplastic transfer to oceans, with contamination pervasive in sediments globally.
• Flooding significantly impacts microplastic distribution and transport in river systems.
• Current understanding of physical controls on microplastic storage and remobilization in rivers is limited, hindering risk assessment.

Purpose of the Study:

• To investigate the physical controls governing microplastic storage, remobilization, and transfer in fluvial sediments during floods.
• To determine how river systems transition from microplastic sinks to sources under flood conditions.
• To assess the predictability of microplastic entrainment and explore management strategies.

Main Methods:

• Controlled flume experiments were conducted to simulate flood conditions and sediment dynamics.
• The evolution of the sediment bed surface was monitored.
• Flood wave characteristics were analyzed in relation to microplastic transport.

Main Results:

• Sediment bed surface evolution and flood wave characteristics dictate the shift from rivers acting as microplastic sinks to sources.
• Similarities were observed between granular transport phenomena and microplastic entrainment during floods.
• Microplastic release from sediment beds is predictable and potentially manageable.

Conclusions:

• Microplastic transport in rivers during floods is governed by physical processes analogous to sediment transport.
• Management of flow-controlled systems offers a potential strategy to mitigate microplastic release from riverine sediments.
• These findings pave the way for remediating legacy microplastic pollution in river systems.