Geochemical imprints of occurrence, vertical distribution and sources of aliphatic hydrocarbons, aliphatic ketones, hopanes and steranes in sediment cores from ten Iranian Coral Islands, Persian Gulf

Jafarabadi, Ali Ranjbar; Dashtbozorg, Mehdi; Bakhtiari, Alireza Riyahi; Maisano, Maria; Cappello, Tiziana

Geochemical imprints of occurrence, vertical distribution and sources of aliphatic hydrocarbons, aliphatic ketones, hopanes and steranes in sediment cores from ten Iranian Coral Islands, Persian Gulf

2019

Jafarabadi, Ali Ranjbar | Dashtbozorg, Mehdi | Bakhtiari, Alireza Riyahi | Maisano, Maria | Cappello, Tiziana

The levels, vertical distribution and sources of hydrocarbons and petroleum biomarkers were estimated for the first time in sediment cores (0–40 cm) from ten coral Islands of the Persian Gulf, Iran. Discrepant hydrocarbons, including linear n-alkanes (n-C₁₁ to n-C₄₀) and isoprenoids (AHs), aliphatic ketones (AKs), hopanes and steranes were measured in all core samples, showing mean concentrations ranging from 209 to 5388 μg g⁻¹dw (∑₃₀AH), 2–244 μg g⁻¹-dw (∑₁₃AK), 189–3713 ng g⁻¹dw (∑₃₁hopane) and 42–3864 ng g⁻¹dw (∑₁₅sterane), respectively. All sediment cores were found to be petroleum polluted, with ∑₃₀AH > ∑₃₁hopane > ∑₁₅sterane > ∑₁₃AK, with higher levels recorded at 10–20 cm, mainly at industrial sites. Various diagnostic indices revealed that hydrocarbons derived mainly from anthropogenic inputs, with significant contribution of biogenic origin at sites less polluted. Moreover, total organic carbon (0.24–23.45 mg g⁻¹-dw), terrestrial and marine organic matter had an overwhelming effect on hydrocarbons deposition in sediment cores. Overall, findings provide relevant information for monitoring and preventing petroleum pollution in the sensitive ecosystems of the Persian Gulf.

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