Heavy Metals and Arsenic in Sediments of Xinfengjiang Reservoir and East River in South China: Levels, Source and Health Risk Assessment

Xinfengjiang Reservoir (XFJR) is the largest drinking water source in the southern China, and plays a vital role in supporting the development of China's Pearl River delta. The levels, source Identification, potential ecological risks and health risk of eight metal elements including Zn, Pb, Ni, Mn, Cu, Cr, Cd and As in the sediments of the XFJR and Heyuan section of East River (HYER) were investigated. Sixteen sediment samples were collected from June to July 2016 in XFJR and HYER, and the concentrations of heavy metals (Zn, Pb, Ni, Mn, Cu, Cr, Cd) and As were analyzed simultaneously. Results showed that the contents of Zn, Pb, Ni, Mn, Cu, Cr, Cd and As in surface sediment of XFJR were 76.27, 36.63, 12.23, 293.61, 14.88, 60.38, 0.76 and 18.68 mg / kg , respectively, and were 76.47, 30.95, 24.47, 361.95, 23.80, 91.81, 0.68 and 7.31 mg / kg, respectively, for HYER. The pollution’s levels of the heavy metal and As was in the order of Cd > Zn > Cr > Mn > As > Cu > Ni > Pb. The spatial distribution pattern of heavy metal and As in the surface sediments of the studied area featured high concentrations in the northeastern region and low concentrations in the XFJR, with a gradual decrease along the river flow from north to south. The results of principal component analysis demonstrated that agricultural activities, industrial pollution and water vehicles were the main sources of heavy metals pollution. The potential ecological risk index of the region was 22.02, and the potential ecological risk of heavy metal and As were in the ordered of Ni > Cu > Pb > Cr > Zn > Mn > Cd >As, indicating slight ecological risk. In addition, the non-carcinogenic risk and carcinogenic risk of heavy metal and As in the surface sediment for adult and children were within acceptable level.