Dominant roles of torrential floods and atmospheric deposition revealed by quantitative source apportionment of potentially toxic elements in agricultural soils around a historical mercury mine, Southwest China

Benle Liu; Kang Tian; Yue He; Wenyou Hu; Biao Huang; Xiaohui Zhang; Ling Zhao; Ying Teng

doi:10.1016/j.ecoenv.2022.113854

Dominant roles of torrential floods and atmospheric deposition revealed by quantitative source apportionment of potentially toxic elements in agricultural soils around a historical mercury mine, Southwest China

Ecotoxicol Environ Saf. 2022 Sep 1:242:113854. doi: 10.1016/j.ecoenv.2022.113854. Epub 2022 Jul 8.

Authors

Benle Liu¹, Kang Tian², Yue He³, Wenyou Hu⁴, Biao Huang⁴, Xiaohui Zhang⁵, Ling Zhao⁴, Ying Teng⁴

Affiliations

¹ CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: tiank@issas.ac.cn.
³ Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Nanjing 210042, China. Electronic address: heyue@nies.org.
⁴ CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
⁵ Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.

PMID: 35816843
DOI: 10.1016/j.ecoenv.2022.113854

Abstract

Hg pollution in soils surrounding the Wanshan mercury mine (WMM), once the largest Hg-producing center in China, has been confirmed, neglecting other potential toxic elements (PTEs). Better understanding of the sources and transport pathways of soil PTEs remains insufficient. To response these limitations, eight soil PTEs (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) at two typical agricultural sites, namely AZ and WW that are located near and far from the WMM, respectively, were systemically investigated. The results showed that AZ exhibited significantly higher concentrations of all the PTEs in the surface soil than WW (p < 0.01). Hg and Cd were recognized as the priority control PTEs, with their average concentrations of 21.54 and 1.21 mg kg^-1 at AZ, and 15.79 and 0.48 mg kg^-1 at WW. Those affected PTEs tended to enrich in near-river areas. Atmospheric deposition contributed more to soil Hg than did regular irrigation, but these two sources could not explain the considerable soil Hg accumulation. Three sources, including natural sources, hydraulic transport (torrential floods and regular irrigation) and atmospheric deposition, were identified and quantified based on the positive matrix factorization model, statistical methods and various auxiliary information. Hydraulic transport (mainly torrential floods) dominated the soil Hg input, which could explain 83.8% and 69.8% of the soil Hg input at AZ and WW, respectively. Atmospheric deposition dominated the soil Cd input, explaining 44.3% and 59.9% of the soil Cd input at AZ and WW, respectively. More attention should be given to the safe utilization of agricultural land and long-term monitoring of atmospheric deposition of Hg and Cd. This study could provide insights to prevent PTE diffusion along the above dominant transportation pathways while developing similar mine regions.

Keywords: Atmospheric deposition; Hydraulic transport; Potentially toxic elements; Source apportionment; Wanshan mercury mine.

MeSH terms

Cadmium
China
Environmental Monitoring / methods
Floods
Mercury* / analysis
Metals, Heavy* / analysis
Risk Assessment
Soil
Soil Pollutants* / analysis

Substances

Metals, Heavy
Soil
Soil Pollutants
Cadmium
Mercury