Accumulation and migration of particulate trace metals by artificial flood event of the Yellow River: From Xiaolangdi reservoir to estuary

Jingbo Chen; Ming Liu; Feiyu Wang; Yi Ding; Dejiang Fan; Houjie Wang

doi:10.1016/j.scitotenv.2023.168614

Accumulation and migration of particulate trace metals by artificial flood event of the Yellow River: From Xiaolangdi reservoir to estuary

Sci Total Environ. 2024 Feb 20:912:168614. doi: 10.1016/j.scitotenv.2023.168614. Epub 2023 Nov 20.

Authors

Jingbo Chen¹, Ming Liu², Feiyu Wang¹, Yi Ding¹, Dejiang Fan³, Houjie Wang⁴

Affiliations

¹ College of Marine Geosciences, Ocean University of China, Qingdao 266100, PR China; Key Laboratory of Submarine Geosciences and Prospecting Techniques, MOE, College of Marine Geosciences, Ocean University of China, Qingdao 266100, PR China.
² College of Marine Geosciences, Ocean University of China, Qingdao 266100, PR China; Key Laboratory of Submarine Geosciences and Prospecting Techniques, MOE, College of Marine Geosciences, Ocean University of China, Qingdao 266100, PR China. Electronic address: lm2006happy@ouc.edu.cn.
³ College of Marine Geosciences, Ocean University of China, Qingdao 266100, PR China; Key Laboratory of Submarine Geosciences and Prospecting Techniques, MOE, College of Marine Geosciences, Ocean University of China, Qingdao 266100, PR China; Laboratory for Marine Geology, Laoshan Laboratory, Qingdao 266061, PR China. Electronic address: djfan@ouc.edu.cn.
⁴ College of Marine Geosciences, Ocean University of China, Qingdao 266100, PR China; Key Laboratory of Submarine Geosciences and Prospecting Techniques, MOE, College of Marine Geosciences, Ocean University of China, Qingdao 266100, PR China; Laboratory for Marine Geology, Laoshan Laboratory, Qingdao 266061, PR China. Electronic address: hjwang@ouc.edu.cn.

PMID: 37992843
DOI: 10.1016/j.scitotenv.2023.168614

Abstract

Reservoir construction increasingly alters the natural transport of riverine water and sediment to the sea, including the trace metals and other pollutants. In 2018, an intensive flood event and 412 million tons of sediment were released from the Xiaolangdi dam during the water-sediment regulation of Yellow River, one of the world's largest sediment releases. During the artificial flood event, the surface sediments in Xiaolangdi Reservoir (XLD) and the Yellow River estuary, suspended sediments at Lijin Station were collected. The concentration and speciation of particulate Cr, Ni, Cu, Zn, Cd and Pb, as well as the major geochemical composition were analyzed, to characterize the behaviors of the metals from the reservoir to estuary mixing zone, and elucidate the controlling mechanisms. The results showed that for exogenous phases, Cr, Ni, Cu and Zn were likely bound to the FeMn oxides, whereas Pb and Cd were mainly adsorbed in the carbonates. The trace metals in XLD were stably combined with fine-grained bottom sediments at high concentrations before dam release. During the delivery from reservoir to downstream channel, the binding of Cr, Ni and Cu with FeMn oxides was markedly enhanced. Pb and Cu showed obvious migration from carbonates to FeMn oxides, and Cd and Pb were even released into the water. The accumulation and migration of trace metals were controlled by the adsorption of fine-grained components, especially FeMn oxides and carbonates, and influenced by the oxidizing processes. After entering the estuary, the trace metals were greatly scavenged by reservoir-sourced fine particles, tended to bound to organic matter affected by the reducing environment. Our results suggest that dam regulation and artificial flood events will likely alter the existing forms and redox state of trace metals and the potential environmental effects should be considered.

Keywords: Dam-released flood; Geochemical behaviors; Speciation; Trace metals; Yellow River.