Assessment of heavy metal contamination in water body and riverbed sediments of the Yanghe River in the Bohai Sea, China

Several famous beach bathing places and aquiculture areas locate in the Yanghe River coast of the Bohai Sea, which are very sensitive to the quality of water and sediment from river discharges. To assess heavy metal contamination, heavy metal in water body and riverbed sediments was investigated in the flood and dry seasons in 2013 at 8 sites along the Yanghe River. All heavy metal concentrations in water body were very low and less than the threshold value of drinking water quality standard of China. There was no significant correlation between heavy metal pollution in water body and riverbed sediments. Sediment pollution was assessed by five approaches including pollution load index (PLI), geo-accumulation index (I-geo), potential ecological risk index (RI), cluster analysis (CA) and principal component analysis (PCA). The results of heavy metal contamination in riverbed sediments showed that: (1) the mean PLI in the range of 1.0-1.1 indicated a progressive deterioration, and the I-geo revealed the pollution in the order of Cd > Cu > Zn > Pb > Cr; (2) the RI presented that the pollution in the downstream was much higher than that in the upstream; (3) the contamination decreased in the upstream due to decreased domestic wastewater where far from the development zone Funing Town, while it increased in the downstream because of dense population and tourists in the coastal zone; and (4) the PCA and FA demonstrate that domestic sewage was a major source of heavy metal contamination.