Pollution and source apportionment of heavy metals in the farmland soils of the gold mining area in Tantou Basin, western Henan metallogenic belt

Heavy metals contents of soil samples from the gold mining areas in Tantou Basin of the western Henan metallogenic belt were analyzed to determine the pollution characteristics and sources. The authors used the Cluster analysis and Principal Component Analysis/Absolute Principal Component Scores (PCA/APCS) receptor model to identify the pollution source and its contribution rate. The results showed that the average contents of Hg, As, Cr, Ni, Cu, Pb, Zn, and Cd of the farmland soil in the study area are lower than risk control standard for soil contamination of agricultural land, indicating lower risk of soil pollution in the gold mining area of the Tantou Basin. However, some samples showed excess contents of Hg, As, Cu, Pb, Zn and Cd elements with regional pollution in Pb, Zn, and Cd and point pollution in other heavy metal elements. The variable coefficients of Hg, Cd, and Pb are at a strong variation level, indicating that they were strongly influenced by anthropogenic activities. Combining the results of cluster analysis, principal component analysis and the spatial distribution characteristics, the eight heavy metals mainly come from four types of pollution sources: Cu, Pb, Zn, and Cd pollutions origin from traffic source (PC1); Cr and Ni pollutions come from the natural source (PC2); both As and Hg pollutions are derived from mining source but the former is related to gold mining and tailings stockpiling (PC3) and the latter is related to small workshop mercury dissolution smelting (PC4).