Seasonal variations of microplastics in surface water and sediment in an inland river drinking water source in southern China

Wenyu Zhao; Jing Li; Mengyue Liu; Rui Wang; Boxuan Zhang; Xiang-Zhou Meng; Shengwei Zhang

doi:10.1016/j.scitotenv.2023.168241

Seasonal variations of microplastics in surface water and sediment in an inland river drinking water source in southern China

Sci Total Environ. 2024 Jan 15:908:168241. doi: 10.1016/j.scitotenv.2023.168241. Epub 2023 Oct 31.

Authors

Wenyu Zhao¹, Jing Li², Mengyue Liu³, Rui Wang², Boxuan Zhang⁴, Xiang-Zhou Meng⁴, Shengwei Zhang⁵

Affiliations

¹ School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114,China; Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410004, China.
² State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China.
³ School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114,China.
⁴ State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
⁵ School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114,China; State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China. Electronic address: swz0112@126.com.

PMID: 37914114
DOI: 10.1016/j.scitotenv.2023.168241

Abstract

The aim of this study was to examine microplastic (size distribution of 0.05-5 mm) occurrence and distribution in drinking water source of XJ River during both flooding and dry periods. Surface water and sediment samples were collected from the CS City section of the river in August and December 2020. During the flooding period, microplastic abundances were observed at 0.72-18.6 (7.32 ± 2.36) items L^-1 in surface water and 26.3-302 (150 ± 75.6) items kg^-1 dry weight (dw) in sediment. In the dry period, abundances were slightly higher at 2.88-17.7 (11.0 ± 3.08) items L^-1 and 27.0-651 (249 ± 182) items kg^-1 dw, respectively. Microplastics were found in higher concentrations in urban areas and downstream of wastewater treatment plants, suggesting anthropogenic sources. The diversity in shapes, colors, and types of microplastics in surface waters and sediments indicates specialized enrichment processes and persistent sources of microplastic pollution. Approximately 60 % of the microplastic particles identified fall within the 50-100 μm range. Furthermore, a significant correlation was observed between these smaller-sized particles and the overall prevalence of microplastics. Fourier-transform infrared spectroscopy and scanning electron microscopy indicated that the microplastics had been subjected to weathering in the environment, contributing to the production of oxygen-containing functional groups and surface cleavage features. The utilization of energy dispersive spectroscopy revealed the presence of microplastics associated with various heavy metals, highlighting the intricate nature of microplastic pollution. Moreover, the high abundance of microplastics may pose a potential ecological risk to the aquatic environment of the XJ River. The results of this study demonstrate concerning levels of microplastics in the XJ River, despite its status as a high-quality water source.

Keywords: China; Drinking water source; Microplastics; Risk assessment; River water; Sediments.