Ascertaining the pollution, ecological risk and source of metal(loid)s in the upstream sediment of Danjiang River, China

The study on metal(loid) contamination of sediment in river upstream is lacking. The content, pollution, risk and source of ten metal(loid)s (As, Co, Pb, Cu, Ni, Cr, V, Mn, Ba, and Zn) in the upstream sediment of Danjiang River, China were investigated to explore the environmental quality of headwater area. The pollution levels were ascertained by geo-accumulation index, enrichment factor, and pollution load index and ecological risks were evaluated by sediment quality guidelines (SQGs) and potential ecological risk index. The results indicated that the mean contents of the determined metal(loid)s except As in the sediment exceeded their corresponding background values. All determined metal(loid)s except As, Ni, and Cr in the upstream sediment of Danjing River presented a certain degree pollution. The comprehensive pollution and overall ecological risk of the metal(loid)s in the sediment were moderate. The combination of As, Cu, Cr, Pb, Ni, and Zn in most samples might have 21% probability of being toxicity in terms of the SQGs results. Four main sources were identified for the metal(loid)s: Cu, Ni, Mn, and V were mainly originated from agricultural and natural sources; As, Ba, Pb, and Zn affected by traffic and industrial sources; Co originated from building material and Cr was mainly from natural source.