مشخصات پژوهش

Heavy metals (As, Pb, Cd and Cu) were traced in a model of the aqueous food chain in the Aras River, located in northwest of Iran. The selected model included the zander (Sander lucioperca L.) and crustacean species known as amphipods (Gammarus sp.) which belong to the food chain of this ray-finned fish. A total of 172 samples (70 fish and 102 amphipods) were collected randomly and analyzed for heavy metals using Atomic Absorption Spectrophotometry (AAS). The results showed that the accumulation of heavy metals in both taxa are in the order of As > Pb > Cd > Cu and concentrations of heavy metals in fish muscle are higher than Gammarus sp. in all stations in different seasons. Specimens of station (1) displayed the highest heavy metal content due to local industrial activities. The recorded concentrations of As, Pb, and Cd exceed the permissible limits . There is a close correlation between the concentrations of heavy metals in the amphipods and zanders. Target hazard quotient (THQ), Total target hazard quotient (TTHQ) and Carcinogenic Risk (CR) were calculated to assess risks to human health. The average of THQ for As (1.43) exceeded the international standards and presenting health risks to the consumers of this fish species. The TTHQ for heavy metals was estimated higher than 1. At all stations, the value of CRCd > 1×10-3 indicating the degree of carcinogenicity of this metal in all parts of the Aras River. Therefore, according to our results, efficient control measures and regular biomonitoring should be established in this region.