Sensitivity analysis of a one-dimensional microplastic transport model in turbulent rivers: Intrinsic properties and hydrodynamics

• Published in: Journal of environmental management Vol. 377; p. 124694
• Main Authors: Akdogan, Zeynep, Guven, Basak
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.03.2025
• Subjects: environmental management; Environmental Monitoring; Ergene river; Geologic Sediments; Hydrodynamics; mechanistic models; Microplastic transport; Microplastics; Model sensitivity; Modeling; Models, Theoretical; Plastics; rivers; Rivers - chemistry; roughness; sand; Turbulent flow; Water Movements; Water Pollutants, Chemical; Ergene river; Turbulent flow; Model sensitivity; Microplastic transport; Modeling
• ISSN: 0301-4797; 1095-8630; 1095-8630
• DOI: 10.1016/j.jenvman.2025.124694

Since rivers are major transport routes for microplastics, developing novel modeling approaches has become a subject of research to better understand the transport behavior of these particles in river systems. This study aims to model the vertical transport of microplastics at selected sites of the Ergene River, Türkiye, simulate the concentration dynamics of these particles in water and sediment under different hydrodynamic and morphological conditions, and determine the sensitivity of the model results to parameters related to the physical characteristics of microplastics, as well as river hydrodynamics and morphology. A mechanistic model was developed using data on microplastics, river hydrodynamics and morphology. Mass-balance and hydrodynamic equations were utilized for model construction in GoldSim to predict the transport of microplastics between the water column and sediment. The model results revealed that the residence time of microplastics in water was directly related to flow characteristics and river hydraulics, while the initial concentration of particles in water dominated other parameters in influencing the settling and resuspension fluxes of microplastics. Turbulent conditions affected both flow rate and particle resuspension, suggesting that turbulence can either increase or decrease microplastic concentrations and their residence time in the water column and sediment. The model results for both compartments were most sensitive to changes in water and plastic density, whereas Nikuradse sand roughness was the least significant parameter affecting the model outcomes for both compartments. [Display omitted] •Microplastics' vertical transport was modeled mechanistically in a turbulent river.•Microplastic residence time in water depended on both river flow and morphology.•Initial concentration predominantly affected the vertical fluxes of microplastics.•The model was most sensitive to variations in water and plastic density.