Analysis of trace elements (heavy metal based) in the surface soils of a desert–loess transitional zone in the south of the Tengger Desert

It is very important to strengthen the research about the heavy metal pollution of soil in vulnerable ecological regions of the south-central arid area of Northwest China for regulating and guiding local industrial and municipal activities and for protecting the environment. In this study, 48 surface soil samples were collected in the desert–loess transitional zone in the south of the Tengger Desert. The distributions of elements (heavy metal based) and the differences between urban and natural soils were analyzed. We observed that As, Pb, Cu, Zn and S were clearly enriched in the Baiyin area, and Ni and Cr were mainly enriched in the Zhongwei area. V, Mn, Ti, Bi, Co and W were enriched in the southeast margin of the Tengger Desert, where there is relatively little human activity. Over the entire study area, Ce, La and Nd were widely distributed across regions whether with strong or weak human activity. Based on the distributions of elements, we suggest that in the desert–loess transitional zone in the south of the Tengger Desert, the distribution and abundances of element As, Pb, Cu, Zn, S, Ni and Cr are strongly related to the human activities in the area, but the elements V, Mn, Ti, Bi, Co, W, Ce, La and Nd are derived mainly from natural sources.