Temporal patterns in the abundance, type and composition of microplastics on the coast of the Río de la Plata estuary

Highlights: • Microplastics (MPs) were more abundant in February in water and in April in sediment. • The polymers identified were polyethylene (PE) and polypropylene (PP). • The wind from the NE direction was related to a greater accumulation of MPs in the sediment. • MPs abundance was negatively related to the larger sizes of sediment particles. • The wind from the NW direction was associated with a lower abundance of MPs in the water column. The objective was to establish possible temporal patterns in the microplastics (MPs) abundance in the water and in the intertidal sediment in an urbanized location of the Río de la Plata estuary (Argentina), in relation to environmental factors. The site was sampled monthly for a year (February 2019–January 2020). The presence of MPs was recorded, being more abundant in February in the water (110 MPs m⁻³) and in April in the sediment (613 MPs m⁻²). The types of MPs found were fibers, fragments, pellets, film and foam; while the polymers identified were polyethylene (PE) and polypropylene (PP). Regarding the environmental variables, the predominance of wind from the NE direction was related to a greater accumulation of MPs in the sediment, while wind from the NO direction was associated with a lower abundance of MPs in the water. Also, MPs abundance was negatively related to the larger sizes of sediment particles.