Biomarkers of Catalase, Glutathione S-transferase, and Ethoxyresorufin-O- deethylase in Echinometra mathaei exposed to Polycyclic Aromatic Hydrocarbons in the northern Persian Gulf

The Persian Gulf is a semi-enclosed sea with unique ecological conditions, where the average level of oil pollution exceeds the minimum optimum level established for the global marine environment. Echinoderms are among the most significant marine phyla in this ecosystem, particularly because their bottom-dwelling lifestyle exposes them more to sediment pollution. Numerous biomarkers can effectively indicate the adverse effects of chemical pollutants in the environment. This study investigated the responses of Catalase, Glutathione S-transferase (GST), and Ethoxyresorufin-O-deethylase (EROD) enzymes in Echinometra mathaei specimens collected from the northern Persian Gulf. Sampling was conducted at several locations, including T-wharf Khark, north Khark, Nai-Band, Shirino, Owli, and Shoghab Beach of Bushehr. Enzyme levels were measured during both cold and warm seasons. The maximum and minimum Catalase activity among all stations and seasons were recorded in Shirino (1.95 µmol/min/mg protein) and Bushehr (0.98 µmol/min/mg protein), respectively. The highest and lowest levels of Glutathione-S-Transferase activity were observed at Khark T-wharf (9.30 nmol/min/mg protein) and Nai-Band (6.63 nmol/min/mg protein), respectively. Maximum EROD activity was measured at Khark T-wharf (0.04 µmol/min/mg protein), while the minimum was found in Bushehr (0.002 µmol/min/mg protein). Overall, no significant differences (P > 0.05) were observed regarding the relationship between enzyme activities and the presence of Polycyclic Aromatic Hydrocarbons (PAHs) in different seasons. These results suggest that the sea urchins in the Persian Gulf may possess a distinct immune system or have adapted to the pollution levels prevalent in this area.