Source Apportionment of Heavy Metals in Cultivated Soils of Typical Mining Areas Based on Unmix Model and Isotopic Tracing

The boost up of soil heavy metal pollution has severely affected the sustainable development of agriculture in China. It is essential to control and resolve the dilemma of deteriorating soil health due to pollution of heavy metals. The contribution of sources and relative sources of heavy metals in cultivated land surrounding typical mining area, was accurately analyzed by UNMIX, and isotope tracer. The results reveal that the content of Cu, Zn, Pb and Cd was seriously affected by input of external human activities. The Cr, Ni and As were mainly influenced by soil parent material. The UNMIX models have demonstrated that accumulation of Cd and Pb in farmland soil around lead-zinc mine was mainly from mining and Zn was accumulated from mixed sources in the farmland soil. The isotope tracing revealed that atmospheric deposition and mining activities were the main sources of Cd pollution. The contribution of Cd to comprehensive potential ecological risk is 79.09%, which is the main source of potential ecological risk of heavy metals in the area. In this study, a reliable method for analyzing sources of heavy metals in typical areas was proposed. The combination of UNMIX and isotopic tracing methods have accurately identified and quantified the sources of pollution