Pollution and Distribution of Microplastics in Roadside Soils Along the Main Roads of Qinghai-Tibet Plateau, China

Abstract

Microplastics (MPs) have been widely detected in the environment and are receiving increasing attention as an emerging environmental challenge. However, research on MPs in soils remains limited, especially on the occurrence and distribution of MPs in roadside soils. This study investigated MP pollution in roadside soils in the Qinghai-Tibet Plateau, China. MPs were detected in all the sampling sites. The abundances of MPs in different soil samples ranged between 1,125–1,329 items/kg (mean of 1,201.88 ± 52 items/kg). Various types, shapes, and sizes of MPs were observed. Polyethylene terephthalate (PET) was the dominant plastic in all the roadside soil samples. Small-sized MPs (10–50 μm) accounted for 50% of all of MPs. Pellets represented the dominant MPs form (44.71% of total items). The results of the site survey indicated that litter from tourism was the dominant potential source of MPs in the study area. The results confirmed the presence of large quantities of MPs in the roadside soils of remote areas as well. This study can act as a reference for further studies of MPs in terrestrial systems.

Keywords: microplastics, Roadside soils, pollution, Qinghai-Tibet Plateau