A multivariate analysis of microplastics in soils along the headwaters of Yangtze river on the Tibetan Plateau

Sansan Feng; Hongwei Lu; Yuxuan Xue; Yibo Li; Pengdong Yan; Jingzhao Lu; Hengchen Li; Tong Sun

doi:10.1016/j.jhazmat.2024.134347

A multivariate analysis of microplastics in soils along the headwaters of Yangtze river on the Tibetan Plateau

J Hazard Mater. 2024 Jun 5:471:134347. doi: 10.1016/j.jhazmat.2024.134347. Epub 2024 Apr 18.

Authors

Sansan Feng¹, Hongwei Lu², Yuxuan Xue¹, Yibo Li¹, Pengdong Yan³, Jingzhao Lu⁴, Hengchen Li¹, Tong Sun³

Affiliations

¹ Key Laboratory of Water Cycle and Related Land Surface Process, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Science, Beijing 100101, China.
² Key Laboratory of Water Cycle and Related Land Surface Process, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Science, Beijing 100101, China. Electronic address: luhw@igsnrr.ac.cn.
³ State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, China.
⁴ College of Science and Technology, Hebei Agricultural University, Cangzhou 061100, China.

PMID: 38677115
DOI: 10.1016/j.jhazmat.2024.134347

Abstract

Microplastics (MPs) are among the most widespread anthropogenic pollutants of natural environments, while limited research has focused on the fate of MPs in soils along the Plateau rivers. In this study, we investigated MPs in soils along the source areas of the Yangtze River on the Qinghai-Tibet Plateau. The results showed mean MP abundance values of (89.4 ± 51.0) and (64.4 ± 24.5) items/kg of dry soils around the tributary and mainstream areas, respectively. Film, transparent colors, and polyethylene were common shape, color, and compositions, respectively. The correlation analysis and PCA revealed that MP abundance was related to soil heavy metals (Cr and Ni) and nutrients (TOC and TP) (p < 0.05). Structural equation modeling also revealed that population density was the dominant driving factor contributing to MPs, with a total effect coefficient of 0.45. In addition, the conditional fragmentation model further distinguished the differences in MP sources from upstream to downstream along the Jinsha River. The significant sources of MPs in the bare land and grasslands from the upper reaches of the Jinsha River included traffic, tourism, and atmospheric transport. In contrast, MP transport during farming activities mainly contributed to MPs in the agricultural soil in the lower reaches.

Keywords: Jinsha river; Microplastics; Soil; Source; Tibetan Plateau.