Heavy metal deposition dynamics under improved vegetation in the middle reach of the Yangtze River

Jiaqiong Gong; Wei Ouyang; Mengchang He; Chunye Lin

Environment International (Jan 2023)

Heavy metal deposition dynamics under improved vegetation in the middle reach of the Yangtze River

Jiaqiong Gong,
Wei Ouyang,
Mengchang He,
Chunye Lin

Affiliations

Jiaqiong Gong: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
Wei Ouyang: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China; Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhuhai 519087, China; Corresponding author at: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
Mengchang He: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
Chunye Lin: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China

Journal volume & issue: Vol. 171
p. 107686

Abstract

Read online

Estuarine heavy metal deposition processes in tributaries can reflect the environmental changes in the basin and the contribution of tributaries to the pollution of downstream lakes. The dynamic processes of heavy metal deposition in two major tributaries of the middle reaches of the Yangtze River were explored using sediment cores. The relationships between heavy metals (HMs) and various physicochemical properties were analyzed using Pearson correlation analysis. The sediment chronological sequences were determined using Pb isotope dating, and the sediment fluxes of heavy metals were calculated. The differences in the driving factors of the two watersheds were analyzed using redundancy analysis. The results showed that heavy metal in both sediment cores were significantly higher than the corresponding background values and showed a relatively stable trend from deep to shallow, with Cd being the most exceeded heavy metal in both tributaries. The average sediment deposition rate was 1.31 cm/year. The Pearson correlation analysis (PCA) results between the HMs indicated similar sources, and the correlation analysis between HM and environmental variables showed that the HMs in both cores, especially Cu and Cr, were significantly correlated with phosphorus, suggesting a synergistic loss of HMs and P. Heavy metal deposition and the normalized difference vegetation index (NDVI) in watersheds showed a negative correlation. This negative correlation is more pronounced in watersheds with higher vegetation cover, where heavy metal deposition is more driven by natural factors. The redundancy analysis (RDA) results indicated that the transport of Cd and Cu was influenced by precipitation and runoff. Heavy metal deposition processes in lake estuaries under improved terrestrial vegetation show the historical contribution of tributaries to lakes, which is important for studying pollution and ecological restoration in watersheds.

Published in Environment International

ISSN: 0160-4120 (Print)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Geography. Anthropology. Recreation: Environmental sciences
Website: https://www.journals.elsevier.com/environment-international

About the journal

Abstract

Keywords