Distribution and origin of heavy metals in deep topsoil of the Zhangye Basin in the 1990s
The Zhangye Basin in Gansu Province serves as a national modern agriculture demonstration area in China.The 1990s was the only period that witnessed both agricultural soil surveys and regional geochemical surveys in the area.This study aims to provide da-ta support for investigating the evolution of the regional soil environment in the area.It gathered geochemical survey data of rocks,deep topsoil,and stream sediments,which were sampled by Gansu geophysical and geochemical exploration teams in the Zhangye Basin and its surrounding mountains in the 1990s.Using these data,this study calculated the background values of elements in various geological units as per the Pauta criterion and sampling media.Focusing on heavy metals,it compared their regional background values in deep topsoil with the nationalsoil background values and the coetaneous averages of farming soil elements surveyed by the agricultural sector,as well as the soil background values of Quaternary sediments with the regional background values.Moreover,it combined geochemical hybrid models with geographical factors.Finally,it explored the distribution characteristics and material sources of heavy metals in deep topsoil of the Zhangye Basin in the 1990s.Compared to the national soil background values,the deep topsoil was enriched in Cu and Cd but depleted in Zn.Contrasting with contemporaneous farming soil,the deep topsoil was significantly enriched in Cr but promi-nently depleted in Cu,Zn,Pb,and As.In terms of sources,heavy metals Zn,Cd,and As were principally derived from the northern Qilian Mountains,Pb originated from the Longshou Mountains,and Hg and Cr might be primarily associated with human activities.The abnormal H3 potential ecological risk index of the deep topsoil resulted from the combined effect of northwest and southeast winds.The enrichment of heavy metals in deep topsoil was positively correlated with human activity intensity but negatively correlated with neotec-tonic movement intensity.
soildeep topsoilheavy mentalmaterial sourceZhangye BasinGansu Province
国家科技期刊平台
NSTL
万方数据
