Ecological risk assessment of heavy metals in water and sediment of the Pearl River Estuary, China

The concentration of heavy metals (Cr, Cd, Pb, Cu, Zn, Co, Ni and Tl) in water and surface sediment were investigated in the Pearl River Estuary, China. The concentrations of heavy metals in sediment were 1000-100,000 times higher than those in water. Correlation analysis and principal component analysis found that heavy metals (Zn, Cr, Pb and Co) in water may originate from anthropogenic activities, but the heavy metals in sediment indicate that Pb was dominated by nature and Zn, Cr, Co, Cd, Cu, Tl and Ni were mostly influenced by anthropogenic pollution. Enrichment factor and accumulation index of sediment heavy metal concentrations showed that S5, S6 and S7 presented a relatively serious pollution.