Contamination, sources and health risks of potentially toxic elements in the coastal multimedia environment of South China

Coastal ecosystems are vulnerable to the accumulation of potentially toxic elements (PTEs), which pose a threat to ma-rine ecosystems and human health. In this study, the concentrations of eight PTEs in a typical area of South China were analysed, and their distributions, seasonal variations, pollution degrees, potential health risks and sources in seawater, sediment and organisms were evaluated. The comprehensive pollution index (CPI), pollution load index (PLI), poten-tial ecological risk index (PERI) and target hazard quotient (THQ) were applied to assess seawater, sediment and or-ganism quality, respectively. The annual mean concentrations of Zn, Hg, Cr and As in the bottom seawater were higher than those in the surface water while those of Pb, Mn and Cu were higher in the surface seawater. The mean content of Hg was higher than the corresponding background value of that in China Shelf Sea sediment. Marine organ-isms have a high enrichment capacity for Cu, Zn, Cr, Hg, As and Mn in seawater. Based on CPI, the seawater was gen-erally not polluted by PTEs. The PLI and PERI results demonstrated that Hg was the main contamination element in surface sediment. The total target hazard quotient (TTHQ) analysis illustrated that long-term consumption of some fish by children poses a noncarcinogenic health risk, while that risk to adults is negligible. Natural sources, agricultural activity sources, coal burning and industrial emission sources were the main sources of the PTEs in surface sediments according to positive matrix factorization (PMF) model.