Geochemical speciation and ecological risk assessment of selected metals in the surface sediments of the northern Persian Gulf.

The present study aimed to geochemical speciation of metals in the surface sediments of the northern Persian Gulf. Metal contents in the sediment were observed in the order: Al>Fe>Cr>Ni>V>Zn>Cu>Co>As>Pb>Cd. The results of sequential extraction procedure revealed that all metals were predominantly associated with the residual fraction. Among the metals, Cu and As exhibited higher bioavailability. The risk assessment code (RAC) indicated that Cu, As and Cd had medium environmental risk at some sampling sites. Based on enrichment factor (EF), Cd and As had moderate to significant enrichment.

Baseline of polycyclic aromatic hydrocarbons in the surface sediment and sea cucumbers (Holothuria leucospilota and Stichopus hermanni) in the northern parts of Persian Gulf.

Polycyclic aromatic hydrocarbons (PAHs) were determined in the surface sediments and in the sea cucumbers (Holothuria leucospilota and Stichopus hermanni) from around six Islands in the northern parts of Persian Gulf. The ranges of the average concentrations of PAHs in surface sediments, H. leucospilota and S. hermanni were 10.33-186.16ngg(-1) dw, 12.49-505.44ngg(-1) dw and 8.08-389.39ngg(-1) dw, respectively. The spatial distribution of PAHs reveals that pollutant concentration is relatively higher at the western parts of Persian Gulf. International sedimentary quality guidelines (TEL-PEL) indicated a low probability of harmful effects to benthic organisms. PAH source identification showed that the PAHs in the sediments come from pyrogenic and mixed origin.