Influence of Natural and Anthropogenic Factors on the Spatial Distribution of Soil Trace Elements in South-Central Ganzhou District, Zhangye City, China

Abstract

The Qilian Mountains are an important ecological security barrier in the western part of China. The south-central part of Ganzhou District in Zhangye City is adjacent to the Qilian Mountains, which is an important battlefield for the construction of ecological environment protection in the Qilian Mountains. It is also a key site for studying the effects of natural and anthropogenic factors on soil geochemical characteristics. However, there is insufficient research on the spatial distribution pattern of soil trace elements and the influencing factors in some areas of the Qilian Mountains. In this work. The authors selected 35 sampling sites in the south-central part of Ganzhou District, Zhangye City, and divided them into three layers according to the depth. The authors completed geochemical elemental characterization and Pearson correlation analysis. This paper analyzed the effects of natural and anthropogenic factors on the spatial distribution of soil trace elements. The authors explored in depth the geochemical elemental characteristics of four typical profiles. The results of the study showed that the average values of Hg and Cr elements in the soil were more than twice the background values of the soil in Gansu Province. However, none of the levels exceeded the national screening values for soil contamination risks on agricultural and construction land in the Soil Environmental Quality Standards. Among them, the Profile2 and Profile4 were more intensely affected by anthropogenic influences. The Profile2 was mainly affected by tourism activities and the Profile4 was mainly affected by agricultural activities. The Profile1 and Profile3 were more influenced by natural factors, mainly by the alluvial flooding of the host rock. The elements Cr, Hg, and Mn were considered to be anthropogenic impact elements. As, Cd, Co, Cu, Ni, and Zn were considered natural influence elements. This study revealed the distribution patterns and influencing factors of 10 soil trace elements, which helped to further understand the influence of anthropogenic and natural factors on soil geochemical processes in the Qilian Mountains.