Geochemical Fractionation and Source Identification of Pb and Cd in Riparian Soils and River Sediments from Three Lower Reaches Located in the Pearl River Delta

Shaowen Xie; Chengshuai Liu; Bin He; Manjia Chen; Ting Gao; Xinghu Wei; Yuhui Liu; Yafei Xia; Qianying Sun

doi:10.3390/ijerph192113819

Geochemical Fractionation and Source Identification of Pb and Cd in Riparian Soils and River Sediments from Three Lower Reaches Located in the Pearl River Delta

Int J Environ Res Public Health. 2022 Oct 24;19(21):13819. doi: 10.3390/ijerph192113819.

Authors

Shaowen Xie^{1

2

3}, Chengshuai Liu^{2

3

4}, Bin He³, Manjia Chen³, Ting Gao⁴, Xinghu Wei¹, Yuhui Liu⁴, Yafei Xia⁴, Qianying Sun^{3

5}

Affiliations

¹ School of Environmental and Chemical Engineering, Foshan University, Foshan 528000, China.
² Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China.
³ National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.
⁴ State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
⁵ South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China.

Abstract

Pb and Cd accumulation in riparian soils and river sediments in river basins is a challenging pollution issue due to the persistence and bioaccumulation of these two trace metals. Understanding the migration characteristics and input sources of these metals is the key to preventing metal pollution. This study was conducted to explore the contents, geochemical fractionation, and input sources of Pb and Cd in riparian soils and river sediments from three lower reaches of the Pearl River Delta located in the Guangdong-Hong Kong-Macao Greater Bay Area. The total concentration of all Pb and Cd values exceeded the background values to varying degrees, and the exchangeable fraction of Cd in riparian soils and river sediments accounted for the largest proportion, while that of Pb was dominated by the residual fraction. Geoaccumulation index calculations showed that in the riparian soils, the average accumulation degree of Pb (0.52) in the Beijiang River (BJR) was the highest, while that of Cd (2.04) in the Xijiang River (XJR) was the highest. Unlike that in riparian soils, the maximum accumulation of Pb (0.76) and Cd (3.01) in river sediments both occurred in the BJR. Furthermore, the enrichment factor results also showed that Pb and Cd in the riparian soils and river sediments along the BJR were higher than those in the XJR and Dongjiang River (DJR). The relationship between enrichment factors and nonresidual fractions further proved that the enrichment factors of Cd were significantly correlated with the nonresidual fractions of Cd, which may imply various anthropogenic sources of Cd in the three reaches. Moreover, source identification based on principal component analysis (PCA) and Pb isotope ratio analysis indicated that riparian soils and river sediments have inconsistent pollution source structures. The PCA results showed that Pb and Cd were homologous inputs in the DJR, and there were significant differences only in the riparian soils and river sediments. Pb isotope tracing results further showed that the bedrock of high geological background from upstream may be the main reason for Cd accumulation in the XJR. However, the ultrahigh accumulation of Cd in the BJR is mainly caused by the input of the upstream mining and metallurgy industry. The control of upstream input sources will be the key to the prevention of trace metal pollution in these regions.

Keywords: Guangdong–Hong Kong–Macao Greater Bay Area; Pb and Cd; riparian soils; river sediments; source identification.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cadmium / analysis
China
Environmental Monitoring / methods
Geologic Sediments / chemistry
Lead / analysis
Metals, Heavy* / analysis
Risk Assessment / methods
Rivers / chemistry
Soil / chemistry
Trace Elements* / analysis
Water Pollutants, Chemical* / analysis

Substances

Soil
Metals, Heavy
Cadmium
Lead
Water Pollutants, Chemical
Trace Elements

Grants and funding

This study was financially supported by the Laboratory of Lingnan Modern Agriculture Project (NZ2021026), GDAS’ Project of Science and Technology Development (2020GDASYL-20200301003), GDAS’ Project of Science and Technology Development (2020GDASYL-20200103083), and the Science and Technology Foundation of Guangzhou, China (202201011082).