Microplastics and Microfibers in River Sediments: A Review of Current Literature and New Data from Texas Rivers

Abstract

Microplastics in the Earth system are now widely documented and assessed. As plastic production continues and recycling capabilities lag, however, continued monitoring of their accumulation and transport within fluvial systems is necessary for managing the ecological and geomorphic effects of their presence. In addition to plastic pellets, particles, and beads, synthetic fibers and fibers coated with synthetic dye are increasingly causing concern due to their sheer numbers in the natural environment. This study presents a comprehensive review of the current literature regarding microplastics and microfibers in the environment and their potential impact on fluvial systems. In addition, data are presented that demonstrate the presence and prevalence of microfibers in select Texas rivers. Bed sediment from the Brazos, Colorado, and Trinity Rivers was sampled and assessed during the years 2020–2021. Fibers were present in nearly all samples, most abundantly immediately downstream of urban centers. Such sampling efforts should be taken regularly in ecological and geomorphic systems to monitor the temporal accumulation of plastic particles and fibers. These may have direct or cascading effects on ecological and human health. Increasing synthetic sediment may also influence the geomorphic adjustment of river channels by alterations to biogeomorphology and hydraulic processes