Mapping Chemical Earth Program: Progress and challenge
| Autor: | Zhixuan Han, Yanfang Gao, Hui Wu, Dongsheng Liu, Qingqing Liu, Shanfa Xu, Wang Wei, Bimin Zhang, Rui-Hong Li, Qinhua Chi, Taotao Yan, Qinghai Hu, Hanliang Liu, Baoyun Zhang, Mi Tian, Jian Zhou, Lanshi Nie, Xueqiu Wang |
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| Rok vydání: | 2020 |
| Předmět: |
Topsoil
geography geography.geographical_feature_category Drainage basin Sediment Sampling (statistics) 010501 environmental sciences 010502 geochemistry & geophysics 01 natural sciences Soil contamination Geochemistry and Petrology Environmental protection Soil water Environmental science Economic Geology Earth (chemistry) Environmental quality 0105 earth and related environmental sciences |
| Zdroj: | Journal of Geochemical Exploration. 217:106578 |
| ISSN: | 0375-6742 |
| DOI: | 10.1016/j.gexplo.2020.106578 |
| Popis: | There is a critical need to establish a global geochemical observation network to provide data for monitoring the chemical changes of the Earths near-surface environment. The International Centre on Global-scale Geochemistry, under auspices of UNESCO and Government of China, has initiated an International Scientific Cooperation Project called Mapping Chemical Earth. The project focuses on the establishment of Global Geochemical Observatory Network for documenting baselines and changes of nearly all natural chemical elements in the Earths surface and creating a digital Chemical Earth platform allowing anyone to access vast amounts of geochemical data through the Internet. A total area of about 37 million km2, nearly accounting for 27% of the global land, has been covered by global-/continental-scale sampling. Comparing the data of China, the US, Europe and Australia, the percentage of sites with toxic metals exceeding the risk limits of soil pollution according to “Environmental Quality Standard for Soil of China (GB 15618-1995)” to the total sample sites is 30.9%, 17.1%, 23.5% and 10.9% in Europe, China, USA, and Australia respectively. Comparing the China datasets of 15 years interval sampling between 1994, 1995 and in 2008–2012, toxic metals of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn, particularly Cd at top soils significantly increase from 1990s to 2010s. The proportion of top soil samples exceeding the China Standard risk limit of 0.2 mg/kg Cd increases from 12.2% to 24.9%. The facts show that chemical changes of toxic metals induced by human activities can be well observed using catchment sediment sampling. |
| Databáze: | OpenAIRE |
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