Spatial differentiation and influencing factors of heavy metals in soils of typical counties in Lhasa river basin

Abstract This paper studied the spatial distribution and influencing factors of heavy metals (HMs) such as Cu, Pb, Zn, Cr, Ni, Cd and As in the soil of Linzhou County in the Lhasa River basin. By collecting 504 surface soil samples, using descriptive statistics, Kriging interpolation and geoaccumulation index methods, combined with the geographic detector model, the spatial distribution characteristics of soil HMs content and its interaction with 19 environmental factors were systematically analyzed.The results showed that the content of heavy metals in the soil in this area was generally higher than the background value of soil in Lhasa, especially Cd and As, which showed strong spatial heterogeneity, suggesting the existence of specific pollution sources.Although the average HMs content was lower than the soil pollution risk screening value, the As, Cd, Pb and Zn contents at some sampling points exceeded the standard, indicating a high pollution risk in some local areas.The spatial distribution of HMs was uneven, with high-value areas of Pb, Zn and Cd mainly concentrated in the west, Cu concentrated in the northwest, while high-value areas of Cr and Ni were similar, mainly concentrated in the west and central regions. Correlation analysis and geodetector models revealed that traffic pollution and soil texture characteristics were the main environmental factors affecting the spatial variation of soil HMs content, and the distance from national highways and urban roads had a particularly significant relationship with Sc and TK.The study provided a scientific basis for the prevention and control of HMs pollution in soil in high-altitude and cold areas, and recommends targeted environmental management and restoration measures.