张掖盆地1990s表土层深部土壤重金属分布特征及其来源分析  

Distribution and origin of heavy metals in deep topsoil of the Zhangye Basin in the 1990s

作　　者：何甘地 何进忠[1] 牛洪斌 张忠平[1] HE Gan-Di;HE Jin-Zhong;NIU Hong-Bin;ZHANG Zhong-Ping(Geological Survey of Gansu Province,Lanzhou 730000,China;Gansu Provincial Bureau of Geology and Mineral Exploration&Development,Lanzhou 730000,China)

机构地区：[1]甘肃省地质调查院,甘肃兰州730000 [2]甘肃省地质矿产勘查开发局,甘肃兰州730000

出　　处：《物探与化探》2024年第5期1388-1399,共12页Geophysical and Geochemical Exploration

基　　金：中国地质调查局地质调查项目(121201004000150017-35);甘肃省自然资源厅科技创新项目(202231)。

摘　　要：甘肃省张掖盆地是国家现代农业示范区,也是1990s迄今唯一农业土壤调查与区域地球化学勘查相重合的地区。笔者搜集了1990s甘肃省物探队与化探队在张掖盆地及其周围山地采集的岩石、表土层深部土壤和水系沉积物的地球化学调查数据,按照拉依达法则和采样介质计算了元素在各个地质单元中的背景值;进而以重金属为主线,采用将区域表土层深部土壤背景值与中国土壤背景值和同时期耕作层土壤平均值作对比、第四系地层土壤背景值与区域土壤背景值作对比,以及将地球化学混合模型与地理学要素相结合的方法,探讨1990s张掖盆地表土层深部土壤重金属分布特征及其物质来源。相对中国土壤元素背景值,研究区表土层深部土壤富集Cu和Cd,贫Zn;与同时期耕作层土壤相比,Cr显著富集,Cu、Zn、Pb和As显著贫化。重金属Zn、Cd和As主要源于北祁连;Pb来源于龙首山;Hg和Cr可能主要与人类活动有关;表土层深部土壤中的H3潜在生态风险指数异常是西北风和东南风共同作用的结果。重金属在表土层深部土壤中的富集程度与人类活动强度正相关,与新构造运动强度负相关。本次研究为探讨该区区域土壤环境演化提供了科学数据。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 data 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 prominently 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 neotectonic movement intensity.

关 键 词：土壤 表土层深部土壤 重金属 物质来源 张掖盆地 甘肃 

分 类 号：X142[环境科学与工程—环境科学] X825