Document Type : Research Paper

Authors

• narjes okati ¹
• Zahedeh Rahmanikhah ²

¹ Department of Environment, Faculty of natural resources, Zabol University, Zabol city, Iran

² PhD's degree in environmental pollution, Tarbiat Modares University

Abstract

Shadgan wetland is the largest international wetland in Iran and the livelihood needs of local communities depend on it. Therefore, the health of wetland fish is of great importance as the main source of food for marginal residents. Mercury as an accumulating pollutant was studied in aquatic food chains. Based on this, 3 fish species were sampled including binni, carp, and tilapia in the fishing season and the water of wetland was sampled in spring and summer from three selected stations. Mercury concentration in fish tissue was measured using direct mercury analyzer (DMA 80) device and in water samples with atomic absorption device. To determine the permissible limit of mercury in wetalnd water, based on USEPA guidelines, the mercury bioaccumulation factor (BAF) in the food chain in wetland water and mercury concentration criterion in fish tissue (TRC) were calculated based on the consumption pattern of wetland residents. The average mercury concentration of water samples was 0.11 µg/l in the summer season. The mean concentration of mercury in Shadegan wetland fish was 22.18 µg/kg wet weight. The average BAF of mercury was 41.69 l/kg. The mean of TRC of the wetland was 22 µg/kg, and the permissible limit of mercury in the wetland water was 0.53 µg/l. Although the amount of mercury in the water and fish of the weland was lower than the USEPA standard limits; but the high consumption of fish by local people and the higher average amount of mercury in wetland fish compared to the calculated TRC indicate the possibility of mercury risk to the health of local consumers. It is also necessary to monitor mercury pollution in this wetland.

Keywords

• Standard limit
• mercury
• Shadegan wetland
• BAF
• RSC