Comprehensive risk assessment and source apportionment of heavy metal contamination in the surface sediment of the Yangtze River Anqing section, China

The Yangzi River has been seriously affected by intensive anthropogenic activities in recent years. In this study, the levels and distribution, risk assessment, and source apportionment of heavy metals in sediments were investigated in the Yangtze River (Anqing section). The heavy metal concentration and chemical characteristics (Cu/Pb/Zn/Cd/Cr/As/Hg) of 16 samples over four sections were measured using Atomic Fluorescence Spectrometry and Graphite Furnace Atomic Absorption Spectrometry. The metal concentration in the study area showed variance in different sampling sites. The mean heavy metal content was also higher than the background value. Vertical analysis of metal concentration showed the decreasing order from surface sediment. The analysis of Hakanson’s potential risk assessment indicated that the total potential ecological risk of these elements amounted to a considerable pollution level in the study area. The result of geo-accumulation index indicated that the risk of the studied metals had the following decreasing order: Cd > Hg > Pb > Cu > Zn > As > Cr. Based on the result of enrichment factor and principal component analysis, Cr, As, Hg, and partly Zn, Cu, and Cd mostly originated from natural sources. Pb and partly Cu and Zn mostly originated from gas companies, industries, and traffic sources, whereas Cd and partly Zn represented agricultural activities, such as fertilizer and pesticide consumption.