Microplastic in Dredged Sediments: From Databases to Strategic Responses

Area of Science:

• Environmental Science
• Ecotoxicology
• Sedimentology

Background:

• Microplastics (MPs) are pervasive environmental contaminants accumulating in aquatic sediments.
• Current guidelines for assessing MP risks in dredged sediments are insufficient.
• Understanding MP distribution in sediments is crucial for effective environmental management.

Purpose of the Study:

• To synthesize existing literature on microplastics in sediments.
• To improve fundamental knowledge of microplastic exposure in sediment environments.
• To develop a publicly accessible database of microplastic concentrations in sediments.

Main Methods:

• Systematic literature review of studies reporting microplastic concentrations in sediments.
• Analysis of microplastic distribution in sediment cores (depth profiles).
• Comparison of microplastic concentrations across various aquatic environments (lakes, rivers, marine, harbors).

Main Results:

• Microplastics were detected in nearly all evaluated surficial sediment samples (0-15 cm depth).
• Sediment core samples showed microplastic concentrations generally decreasing with depth, peaking in the top 15 cm.
• Median microplastic concentrations varied significantly by environment, with harbors and dredging activities showing the highest levels.

Conclusions:

• Dredged sediments can contain substantial microplastic loads, influenced by factors like sediment depth and time since last dredging.
• The findings provide critical insights for environmental monitoring and risk assessment of microplastics in dredged materials.
• A comprehensive database of microplastics in sediments is needed to support regulatory efforts.