Integrating land cover, point source pollution, and watershed hydrologic processes data to understand the distribution of microplastics in riverbed sediments. (15th October 2022)

• Record Type: Journal Article
• Authors: Baraza, Teresa; Hernandez, Natalie F.; Sebok, Jack N.; Wu, Chin-Lung; Hasenmueller, Elizabeth A.; Knouft, Jason H.
• Is Part Of: Environmental pollution. Volume 311(2022)
• Publication Date: 2022-10-15
• Subjects: Microplastics -- Contaminant transport -- Point source pollution -- Land cover -- Watershed modeling -- SWAT; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2022.119852
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Microplastics are emerging contaminants ubiquitously distributed in the environment, with rivers acting as their main mode of transport in surface freshwater systems. However, the relative importance of hydrologic processes and source-related variables for benthic microplastic distribution in river sediments is not well understood. We therefore sampled and characterized microplastics in river sediments across the Meramec River watershed (eastern Missouri, United States) and applied a hydrologic modeling approach to estimate the relative importance of river discharge, river sediment load, land cover, and point source pollution sites to understand how these environmental factors affect microplastic distribution in benthic sediments. We found that the best model for the Meramec River watershed includes both source-related variables (land cover and point sources) but excludes both hydrologic transport-related variables (discharge and sediment load). Prior work has drawn similar and dissimilar conclusions regarding the importance of anthropogenic versus hydrologic variables in microplastic distribution, though we acknowledge that comparisons are limited by methodological differences. Nevertheless, our findings highlight the complexity of microplastic pollution in freshwater systems. While generating a universal predictive model might be challenging to achieve, our study demonstrates the potential of using a modeling approach to determine the controlling factors for benthic microplastic distribution in fluvial systems. Graphical abstract: Image 1 Highlights: Riverbed sediment was collected to characterize benthic microplastic distribution. Microplastic content was related to environmental variables through modeling. Source-related variables were the best indicators for microplastic pollution. Hydrologic transport-related variables were not important for the final model. Our approach can help identify controls on microplastic distributions in watersheds.