Identification of the sources and influencing factors of potentially toxic elements accumulation in the soil from a typical karst region in Guangxi, Southwest China

Zhenyi Jia; Junxiao Wang; Xiaodan Zhou; Yujie Zhou; Yan Li; Baojie Li; Shenglu Zhou

doi:10.1016/j.envpol.2019.113505

Identification of the sources and influencing factors of potentially toxic elements accumulation in the soil from a typical karst region in Guangxi, Southwest China

Environ Pollut. 2020 Jan:256:113505. doi: 10.1016/j.envpol.2019.113505. Epub 2019 Oct 31.

Authors

Zhenyi Jia¹, Junxiao Wang², Xiaodan Zhou³, Yujie Zhou⁴, Yan Li⁵, Baojie Li⁶, Shenglu Zhou⁷

Affiliations

¹ School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China; Key Laboratory of Coastal Zone Exploitation and Protection, Ministry of Land and Resources, Nanjing, 210017, China. Electronic address: zhenyijay@smail.nju.edu.cn.
² School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China; Key Laboratory of Coastal Zone Exploitation and Protection, Ministry of Land and Resources, Nanjing, 210017, China. Electronic address: njuwjx@outlook.com.
³ Key Laboratory of Coastal Zone Exploitation and Protection, Ministry of Land and Resources, Nanjing, 210017, China; Research Center of Land and Resources of Jiangsu Province, Nanjing, 210017, China. Electronic address: 3534464243@qq.com.
⁴ School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China; Key Laboratory of Coastal Zone Exploitation and Protection, Ministry of Land and Resources, Nanjing, 210017, China. Electronic address: dg1827052@smail.nju.edu.cn.
⁵ College of Forestry, Nanjing Forestry University, Nanjing, 210037, China. Electronic address: dg1627013@smail.nju.edu.cn.
⁶ School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China. Electronic address: baojieli@smail.nju.edu.cn.
⁷ School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China; Key Laboratory of Coastal Zone Exploitation and Protection, Ministry of Land and Resources, Nanjing, 210017, China. Electronic address: zhousl@nju.edu.cn.

PMID: 31706759
DOI: 10.1016/j.envpol.2019.113505

Abstract

Southwestern China contains the largest and most well-developed karst region in the world, and the potentially toxic elements (PTEs) content in the soils of the region is remarkably high. To explore the internal and external control factors and sources of soil PTEs enrichment in this area and to provide a basis for the treatment of PTE pollution, 113 soil samples were collected from Hengxian County, a karst region in Guangxi Province, southwestern China. The importance of eighteen influencing factors including parent material, weathering, physicochemical properties, topography and human activities were quantitatively analyzed by (partial) redundancy analysis. The sources of PTEs were identified using the Pb isotope ratio and absolute principal component score/multiple linear regression (APCS-MLR) model. The contents of all soil PTEs were higher than the corresponding background values of Guangxi soils. The contents in Cu, Zn, Cd, Hg and Pb were the highest in the soil from carbonate rock. The factor group of geological background and weathering explained 26.5% for the accumulation and distribution of soil PTEs and the influence of physicochemical properties was less than 2% but increased to 25.6% through interaction with weathering. Fe (47.1%), Al (42.1%), Mn (22%), chemical index of alteration (12.8%) and clay (11.9%) were the key factors affecting the soil PTEs, while the influence of human activities was weak. Pb isotope ratio and APCS-MLR classified 62.8-74% of soil PTEs as derived from natural sources, whereas 18.23% and 18.95% were derived from industrial activities and agricultural practice/traffic emissions, respectively. The Pb isotope ratio showed that the natural sources account for up to 90% of the Pb in the soil from carbonate rock, the highest contribution among the studied soils. The results of the study can provide background information on the soil PTEs contamination in the karst areas of China and other areas worldwide.

Keywords: Karst area; Potentially toxic elements; RDA; Source apportionment; Weathering.

MeSH terms

Agriculture
China
Environmental Monitoring*
Environmental Pollution / analysis
Hazardous Substances / toxicity*
Humans
Mercury / analysis
Metals, Heavy / analysis
Risk Assessment
Soil / chemistry
Soil Pollutants / analysis
Soil Pollutants / toxicity*

Substances

Hazardous Substances
Metals, Heavy
Soil
Soil Pollutants
Mercury