Heavy Metals and Their Ecological Risk Assessment in Surface Sediments of the Changjiang River Estuary and Contiguous East China Sea

Marine heavy metal pollution has been an important global environmental issue in recent years. Concentrations of nine heavy metals (Pb, Cr, Ni, Cu, Zn, Co, Cd, As, and Hg) from marine sediments (2015, n = 38) in the Changjiang River Estuary and contiguous East China Sea were determined. The total contents of nine heavy metals ranged from 134.0 μg/g to 357.8 μg/g, with Cr as the most abundant component. Pearson correlation coefficient matrix of the heavy metals, granularity, and total organic carbon (TOC) in the samples were determined, and a preliminary ecological risk assessment was conducted in three aspects. According to the investigation, heavy metals were commonly found in samples and affected by terrestrial inputs to a large extent. Their concentration distributions were significantly affected by granularity as well as TOC. Preliminary ecological risk assessment showed that Cd and Hg were identified as the dominant heavy metals in the sediment samples from the study areas and showed a strong ecological risk. Overall, the situation of heavy metal pollution in the sediments of the Changjiang River Estuary and contiguous East China Sea was not optimistic in 2015, and it is worthy of further investigation into whether the environmental condition has improved with the strengthening of governmental environmental protection.