Distinguishing anthropogenic and natural sources of trace elements in soils undergoing recent 10-year rapid urbanization: a case of Donggang, Eastern China

A total of 59 samples consisting of 45 topsoils samples and 14 subsoils samples were collected from urban soils of Donggang and were analyzed for soil properties and 12 trace elements. The mean contents of As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Se, V, and Zn in topsoils were 5.76, 0.20, 9.88, 44.82, 17.69, 0.05, 578.96, 19.98, 28.38, 0.21, 58.88, and 58.32 mg kg(-1), respectively. The mean enrichment factor results suggested that Hg, Cd, Pb, Cu, Se, and Zn were enriched in topsoils compared with subsoils. Spatial distribution maps of trace elements indicated that Hg, Cd, Pb, Cu, Se, and Zn had similar patterns, with the highest values in the industrial region. There were no significant associations displayed between spatial distributions of As, Co, Cr, Mn, Ni, and V and the industrial region. Through correlation analysis, stepwise regression analysis, and redundancy analysis, three main sources of 12 trace elements were identified. Cd, Hg, and Se originated from industrial emissions and coal combustion, and As, Co, Cr, Mn, Ni, and V had a lithogenic origin. The combination of human activities and natural sources contributed to the contents of Cu, Pb, and Zn, and the human activities included industrial and traffic emissions.