Distribution and transport of heavy metals in estuarine-inner shelf regions of the East China Sea

This study analyzes the distribution and transportation of heavy metals in surface sediments by determining the concentrations of 6 heavy metals (Cr, Zn, Ni, Pb, Cu, and Cd) based on 164 surface sediments collected from the East China Sea (ECS). The results indicated that concentrations of heavy metals were higher in the south than the north with a clear boundary near 30° N. The distributions of the six heavy metals could be divided into four groups that corresponded well with different sediment components, suggesting that hydrodynamic sorting processes play an important role in the selective transportation of sedimentary heavy metals. In addition, the spatial distributions of heavy metals were more consistent with fine-grained sediments having a grain size lower than 32 μm. Heavy metal concentrations were slightly higher than found in previous studies conducted from 2002 to 2010. In addition, their spatial patterns have changed drastically compared to data from 2006, suggesting that intensive inland human activities have had a profound impact on heavy metal transportation and distribution in the estuarine & inner-shelf regions of the ECS.