Seawater-Groundwater Interaction Governs Trace Metal Zonation in a Coastal Sandy Aquifer

Wang, Zhenyan1; Wang, Qianqian2; Guo, Yifan2; Yu, Shengchao2,3; Xiao, Kai2; Zhang, Yan1; Li, Hailong2; Zheng, Chunmiao2; Geng, Xiaolong4,5; Zhang, Xiaolang6; Li, Huijie7; Wang, Xuejing8

2023-09-01

10.1029/2022WR032828

WATER RESOURCES RESEARCH   Impact Factor & Quartile

0043-1397

1944-7973

Trace metals in the groundwater of coastal sandy aquifers significantly influence the coastal ecosystem, yet the spatiotemporal controls of these metals remain unclear. In this paper, we comprehensively revealed the distribution patterns, key controlling factors, potential ecological risks, and fluxes to the ocean of groundwater trace metals (As, Ba, Cr, Cd, Fe, Mn, Pb, and Zn) in a coastal deep sandy aquifer. The results showed a clear zonation of trace metals in the groundwater in relation to the mixing extent between seawater and terrestrial freshwater. The freshwater zone exhibited a relatively low concentration of trace metals, whereas the freshwater-seawater transition zone showed a substantial quantity of dissolved Fe, Mn, As, and Ba. Seawater-groundwater interactions significantly affected the Fe, Mn, As, and Ba concentrations through redox potential and pH gradients. The tide-driven saline water zone was vulnerable to oceanic environments and anthropogenic activities, resulting in the enrichment of trace metals such as Zn and Cd. Driven by recirculated submarine groundwater discharge (SGD), the concentrations of trace metals in the density-driven saline circulation zone were found to be higher than those in the surrounding areas. The ecological risk index suggested that the freshwater-seawater transition zone posted the highest ecological risks. Trace metal fluxes (i.e., Fe, Mn, and As) via SGD significantly contributed to the total input into the sea, which may have potential impacts on the coastal environments. Our study highlighted the importance of seawater-groundwater interactions on trace element cycling in coastal sandy aquifers.

trace metals coastal groundwater seawater-groundwater interaction ecological risk sandy aquifer

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English

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This work was supported by the National Natural Science Foundation of China (Grants 41890852, 42077173, 42130703), the Shenzhen Science and Technology Innovation Committee (No. JCYJ20190809142417287, 20200925174525002), and the State Environmental Protecti["42077173","42130703","JCYJ20190809142417287"] ; National Natural Science Foundation of China[20200925174525002] ; null[41890852]

Environmental Sciences & Ecology ; Marine & Freshwater Biology ; Water Resources

Environmental Sciences ; Limnology ; Water Resources

WOS:001055249700001

AMER GEOPHYSICAL UNION

ENVIRONMENT/ECOLOGY

Web of Science

1.China Univ Geosci Beijing, Sch Water Resources & Environm, MOE Key Lab Groundwater Circulat & Environm Evolut, Beijing, Peoples R China
2.Southern Univ Sci & Technol, Sch Environm Sci & Engn, State Environm Protect Key Lab Integrated Surface, Shenzhen, Peoples R China
3.Univ Hong Kong, Dept Earth Sci, Hong Kong, Peoples R China
4.Univ Hawaii Manoa, Dept Earth Sci, Honolulu, HI USA
5.Univ Hawaii Manoa, Water Resources Res Ctr, Honolulu, HI USA
6.Ohio State Univ, Sch Earth Sci, Columbus, OH 43210 USA
7.Zhejiang Engn Survey & Design Inst Grp Co LTD, Ningbo, Peoples R China
8.Tianjin Univ, Inst Surface Earth Syst Sci, Sch Earth Syst Sci, Tianjin, Peoples R China

Wang, Zhenyan,Wang, Qianqian,Guo, Yifan,et al. Seawater-Groundwater Interaction Governs Trace Metal Zonation in a Coastal Sandy Aquifer[J]. WATER RESOURCES RESEARCH,2023,59(9).

Wang, Zhenyan.,Wang, Qianqian.,Guo, Yifan.,Yu, Shengchao.,Xiao, Kai.,...&Wang, Xuejing.(2023).Seawater-Groundwater Interaction Governs Trace Metal Zonation in a Coastal Sandy Aquifer.WATER RESOURCES RESEARCH,59(9).

Wang, Zhenyan,et al."Seawater-Groundwater Interaction Governs Trace Metal Zonation in a Coastal Sandy Aquifer".WATER RESOURCES RESEARCH 59.9(2023).