Multi-element features and trace metal sources of road sediment from a mega heavy industrial city in North China

Abstract

As the primary carrier of harmful elements, road sediment poses severe hazards to human health and ecological environment, especially in megacities. Based on the industrial cities in North China, this research focused on the multi-element features and the pollution levels, sources, and spatial distributions of trace metals in road sediment of Shijiazhuang. The mean levels of P (928.4 mg kg−1), S (1446.2 mg kg−1), Cl (783.9 mg kg−1), Br (5.3 mg kg−1), Na2O (2.0%), CaO (9.9%), Co (36.0 mg kg−1), Pb (38.0 mg kg−1), Cu (34.7 mg g−1), Zn (149.1 mg kg−1), Ba (518.1 mg kg−1), and Sr (224.9 mg kg−1) in road sediment were greater than their soil background values. Trace metals in most samples was moderately (75%) and heavily contaminated (15.6%). The industrial areas, congested roads, and residential areas in the northeast, middle and south of Shijiazhuang are the hotspots of trace metals pollution. A comprehensive analysis of trace metals sources indicated that Ni, V, Ga, Rb, Y, Sc, La, Ce, Zr, and Hf were mainly from natural source, which contributed to 34.2% of the total trace metals concentrations. Cu, Pb, Zn, Cr, Ba, Sr, and Mn primarily originated from mixed source, which accounted for 46.5%. Co principally came from building source, which accounted for 19.3%. This study shows that industrial discharges, construction dust and traffic emissions are the primary anthropogenic sources of trace metals in road sediment in the study area.