Contribution of Asian dust to soils in Southeast China estimated with Nd and Pb isotopic compositions
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ORIGINAL ARTICLE
Contribution of Asian dust to soils in Southeast China estimated with Nd and Pb isotopic compositions Jianwu Li1 • Zhaoliang Song1,4 • Lukas Van Zwieten3 • Li Ruan1,2 Feili Li5
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Received: 27 May 2020 / Revised: 7 August 2020 / Accepted: 7 September 2020 Ó Science Press and Institute of Geochemistry, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Asian dust has been identified in subtropical soils of China. Neodymium (Nd) and lead (Pb) elemental and isotopic geochemistry of soils in Southeast China were used to assess the significance of local versus extraneous sources. The eNd(0) values were close to the parent rocks (? 2.9) in the young soils (NSJ); while their values were always negative (* - 3.7) in the old soils (OMJ), implying dust deposition. The young soils contained less Asian dust contribution (\ 8 %) while the old soils contained more than 50 % Asian dust contribution. This implied that dust contributions were gradually increasing with the soil development stage and Asian dust input had become the principal Nd source for the old soils in this area. On the other hand, Pb excesses and low 207Pb/206Pb values (* 0.8503) in near-surface soils indicated a significant anthropogenic Pb addition onto surface soils. The close relationship between the Pb content and isotopic
& Jianwu Li [email protected] & Li Ruan [email protected] 1
Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang A & F University, Hangzhou 311300, China
2
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China
3
New South Wales Department of Primary Industries, 1243 Bruxner Highway, Wollongbar, NSW 2477, Australia
4
Institute of the Surface-Earth System Science Research, Tianjin University, Tianjin 300072, China
5
College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
ratios in the soil profile indicated that the excessive lead in the surface soil was exogenous. These results suggested that Asian dust made up a significant fraction in the old soils, but that local sources (i.e., basalt and anthropogenic) were not trivial in Southeast China. Keywords Aeolian dust Soil genesis Rural soils Basalt
1 Introduction As an important participant in the global biogeochemical cycle, soils receive material transport from the atmosphere (Brantley et al. 2007; Gross et al. 2015). Atmospheric deposition plays an important role in the formation and evolution of global soil (Li et al. 2013a, b; Zeng et al. 2015; Zhao et al. 2018). For instance, Saharan dust has a huge impact on the soil along the Mediterranean coast and throughout Europe; the annual deposition of Asian dust can be as high as 1128.22 kg m-2 in the arid area of northwest China and even formed the famous Loess Plateau (An 2000). The main atmospheric deposition source areas in the world bring up to 800–2000 9 109 kg of dust reduction per year (Lawrence and Neff 2009). The mineral aerosols and mar
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