Environmental fate of microplastics in alpine and canyon-type river-cascade reservoir systems: Large-scale investigation of the Yalong River in the eastern Qinghai-Tibet Plateau

Yixuan Liu; Shaoting Zhao; Dongzhi Wang; Shichen Wang; Xiaofan Ding; Kaiyang Han; Ruiying Wang; Yuyang Kou; Guangqian Zhou; Weibo Shen

doi:10.1016/j.scitotenv.2024.170300

Environmental fate of microplastics in alpine and canyon-type river-cascade reservoir systems: Large-scale investigation of the Yalong River in the eastern Qinghai-Tibet Plateau

Sci Total Environ. 2024 Mar 15:916:170300. doi: 10.1016/j.scitotenv.2024.170300. Epub 2024 Jan 24.

Authors

Yixuan Liu¹, Shaoting Zhao², Dongzhi Wang³, Shichen Wang⁴, Xiaofan Ding³, Kaiyang Han⁴, Ruiying Wang⁵, Yuyang Kou⁴, Guangqian Zhou⁴, Weibo Shen⁶

Affiliations

¹ College of Soil and Water Conservation Science and Engineering (Institute of Soil and Water Conservation), Northwest A&F University, Yangling, Shaanxi 712100, PR China; College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
² Agricultural Technology Promotion Center of Xi'an, Xi'an, Shaanxi 710000, PR China.
³ School of Materials Science and Engineering, University of Jinan, Jinan 250022, PR China.
⁴ College of Science, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
⁵ Xi'an Institute of Environmental Hygiene Sciences, Xi'an, Shaanxi 710075, PR China.
⁶ College of Soil and Water Conservation Science and Engineering (Institute of Soil and Water Conservation), Northwest A&F University, Yangling, Shaanxi 712100, PR China; College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China; College of Science, Northwest A&F University, Yangling, Shaanxi 712100, PR China. Electronic address: shenweibo@nwafu.edu.cn.

PMID: 38272090
DOI: 10.1016/j.scitotenv.2024.170300

Abstract

Reservoirs are regarded as potential collection sites for microplastics (MPs), and ample water resources in plateau regions provide favorable natural conditions for hydroelectric power generation. However, research on the impact of cascade reservoir construction in the plateau region on the fate of MPs within the watershed is limited. In this study, the Yalong River, an alpine canyon river in the eastern Qinghai-Tibet Plateau, was selected as the research area. This study explored the distribution of MPs at various depths in water, sediment, and riverbank soil as well as the formation of "MP communities" within the river-cascade reservoir system. Furthermore, the effects of dam construction on MPs' migration in different environments were analyzed. The results revealed that the abundance of MPs in the water and sediment within the cascade reservoir area (CRA) was significantly higher than that in the river area (RA) (P < 0.001). Additionally, the trend of increasing MPs in water with decreasing altitude was notably slower in CRA. Regarding shape, the proportion of fibers in the water within the CRA was significantly lower than that in the RA, with a smaller vertical migration rate in the water than in the sediment. The proportion of MPs < 500 μm in the water within the CRA was significantly higher than that in the RA. High-density MPs were notably deposited in the reservoir sediments. The analysis of the MP communities revealed that the construction of cascade dams led to relative geographical isolation between different sampling sites, reducing the similarity of MP communities in the CRA. This study established a theoretical foundation for understanding the impact of cascade dam construction on the fate characteristics of MPs and their potential risks in plateau areas.

Keywords: Environmental risk; MP communities; MPs migration; Mountain Gorge River; River-cascade reservoir system.