An enhanced risk assessment framework for microplastics occurring in the Westerscheldt estuary

Area of Science:

• Environmental Science
• Ecotoxicology
• Marine Biology

Background:

• Aquatic microplastic (MP) pollution is a growing global concern.
• Freshwater systems are recognized as key pathways for MPs entering marine environments.
• Limited data exists on MP pollution levels in global freshwater systems.

Purpose of the Study:

• To investigate the abundance, characteristics, and distribution of microplastics in the Scheldt River.
• To assess the ecological and human health risks associated with MP pollution in the Westerscheldt estuary.
• To establish a baseline for understanding MP distribution and inform monitoring strategies.

Main Methods:

• Sampling and quantification of microplastics in river sediments and surface water.
• Characterization of MP size, shape, and polymer types.
• Development and application of risk assessment models using MP concentration, polymer data, and toxicity.

Main Results:

• Sediment samples showed significantly higher MP abundance (15-413 items/kg DW) compared to surface water (0-113 items/m³).
• Small-sized MPs (<500 μm) were predominantly found in sediments.
• Industrial activities were identified as a major source of MP discharge.
• Risk assessment indicated potential adverse effects of MP exposure on the aquatic ecosystem and human health.
• MPs are transported from 'Hotspots' like urban and industrial areas to remote locations.

Conclusions:

• The Scheldt River experiences significant microplastic pollution, particularly in sediments.
• MP pollution poses potential risks to aquatic life and human health, necessitating targeted monitoring and mitigation.
• Understanding MP transport dynamics from pollution sources is crucial for effective environmental management.