Delineation of areas with high geological background values of heavy metals in soils in Yunnan Province,China based on geological big data technology
This study aims to systematically investigate the distribution and over-limit elements of areas with high geological background values of heavy metals in soils in Yunnan Province.GIS spatial analysis was conducted based on the heavy metal content data from a province-wide 1 ∶ 200,000 stream sediment survey and the regional geological map.The analysis results were validated using the data of heavy metals in soils in Kunming,Yuxi,Zhaotong,and other regions.A total of 61 geological units were identified,with heavy met-al content in soils exceeding the screening values of agricultural land,accounting for 21.09%of the total land area of Yunnan.The cultivated land in high geological background areas covers an area of approximately 2.844 1 million hectares,accounting for 7.22%of the total land area of Yunnan.The lithologies that cause over-limit heavy metals in soils primarily comprise carbonate rocks,mafic-ul-tramafic volcanic rocks,intermediate mafic intrusive rocks,coal-bearing clastic rocks,and clastic rocks with mafic components.The o-ver-limit heavy metal elements in high geological background areas are dominated by Cu,Cr,Ni,and Cd.In contrast,As manifests an over-limit risk mainly in carbonate rock formations,Pb and Zn only exhibit an over-limit risk in individual strata,and Hg almost shows no over-limit risk.
heavy metal in soilhigh geological background areageological big data30 m global land cover dataYunnan Province
万方数据
维普
