Survey the Eco toxicological potential of pseudo-estrogenic contaminants in estuaries of Iranian coasts of Caspian Sea

Pollution of aquatic ecosystems, including lakes and seas, has become a serious and growing threat to humans and living organisms. The quality of these ecosystems is one of the most important factors for saving the biodiversity and pollutants which can pose serious effects on plants and living organisms. The Caspian Sea is of global importance due to its biodiversity and special geographical conditions. At the same time, due to the high density of urbanization and the existence of various industrial and agricultural activities on the Iranian shores of the Caspian Sea, the qualitative study of rivers has so importance. Therefore, the purpose of this study was to evaluate the concentration of some pseudo estrogenic compounds and their Eco toxicological risk potential in Iran’s river estuaries of Caspian Sea.  To assess the concentration of Nonylphenol (NP) and bisphenol A (BPA) in Iran’s rivers of Caspian Sea, Water samples were collected from 49 estuaries along the coasts of Gillan, Mazandaran and Golestan provinces. After preparation of samples in laboratory, the concentration of NP and BPA was evaluated and Eco toxicological risk assessment was measured with Risk quotion, RQ categories in three levels including low (RQ<0.1), moderate (0.1≤RQ≤1) and high risk (RQ≤1). High Eco toxicological risk for BPA (for fishes) was characterized in Tala River, 18 rivers presenting medium and other rivers performing low risk. Comparing to BPA, NP showed a greater hazard quotient for fishes. The ecological risk assessment has shown that BPA and NP pose a threat to organisms in southern coasts of the Caspian Sea. In conclusion, this study revealed that pollution sources may occurs due to agricultural, urban and industrial wastewater. Therefore, it is required to control direct flow of wastes from different activities, especially urban wastewater to restore ecological health of estuaries of Caspian Sea.