Contamination Status and Risk Assessment of Lead Metal in Fish of Persian Gulf, Oman Sea and Caspian Sea- Narrative review

Lead is a toxic metal that is highly distributed in the environment and enters the natural cycle through many human-made industrial, agricultural, urban and rural activities, as well as by entering the marine ecosystems, it accumulates in the cycle of food and fish and can cause very dangerous and carcinogenic diseases in humans. This review was conducted in 2022. The data needed to assess the risk of lead on fish in the Caspian Sea, Oman sea and the Persian Gulf were collected by reviewing Persian and English published articles. The findings showed that the range of lead concentration in Caspian Sea fish was from 0.03 mg/kg in Vimba vimba to 3.01 mg/kg in golden grey mullet. Among the fish of the Persian Gulf and the Oman Sea, the highest amount of lead was found in the flounders (2.82 mg/kg) and the lowest amount of this metal was found in sulpdur goatfish (0.008 mg/kg). The amount of lead in the muscle of the fish studied in the Caspian Sea, such as Caspian kutum, Golden grey mullet, common carp, leaping mullet, Gobies, and common Pike, was higher than the permissible limit of the World Health Organization (WHO) standard (0.2 mg/kg). In fish in the Persian Gulf and the Oman Sea, the levels of lead in the muscles of Narrow-barred Spanish mackerel, Tigertooth croaker, Indo-Pacific king mackerel, Chelon subviridis, blackspotted croaker, Cobia, Sillaginidae, and Flounder were reported to be higher than the WHO limit. According to the risk assessment of lead metal in the fishes, in many cases the risk index was higher than 1 and the carcinogenic risk index of lead in the muscle of many fishes was reported to be higher than 1×10-4. Therefore, according to these results, it can be concluded that many fish in the Caspian Sea, the Persian Gulf, and the Oman Sea have been contaminated with lead metal during the past years, and for human consumption, the necessary precautions should be taken based on the recommendations of the WHO. It is also suggested to continuously monitor and control the concentration of lead metal and other heavy metals in marine ecosystems.