Speciation and risk assessment of selected trace metals in bottom sediment of coral reef ecosystems of the Persian Gulf.

To evaluate the hazard assessment of anthropogenic activities on coastal ecosystems, fractionation and bioaccumulation of trace metals were carried out for sediment and coral samples of three distinct habitats including petroleum exploration area of Kharg, the rural harbor of Chirouyeh, and unpopulated area of Hendorabi. Fractionation results suggested that Ni (~ 51%), Pb (~ 49%), and V (~ 45%) in Kharg; Ni (~ 46%), Pb (~ 84%), and Zn (~ 47%) in Chirouyeh; and Cd (~ 51%) in Hendorabi were the predominant metals in the non-resistant fractions of the sediment samples. Risk Assessment Code (RAC), individual contamination factor (ICF), and global contamination factor (GCF) were derived. The highest relative risk for Cd, Cu, and Ti was observed in Kharg, whereas the highest relative risk for Ni, Pb, V, and Zn was recorded in Chirouyeh. The lowest risk for almost all of the trace metals was observed in Hendorabi. Biota-sediment accumulation factor (BSAF) values of coral samples revealed that species examined in the present study are reliable biomonitors for Cd, Ni, Pb, and Zn contamination. Principal component analysis (PCA) and Pearson's correlation coefficient (PCC) suggested that Pb, Ni, and Zn can be considered the main pollutants of the Persian Gulf which originated mainly from petroleum industries. Furthermore, the metal uptake rates of coral samples seemed to be dependent on bioabsorption pathways and coral species. Overall, the present work constitutes a good basis for further studies on trace metal fractionation, risk assessment, and source apportionment in the Persian Gulf, which could contribute to more effective decisions for reducing the anthropogenic trace metal pollution.