Investigation on Heavy Metals Contamination in the Latyan Reservoir Dam, with Special Reference to Role of Sediments on Controlling the Pollutants

The anthropogenic and natural contaminants are considered as the main factors threatening water resources and they are in direct connection to the public health and also threaten the development of water resources. The Latyan Dam reservoir is the main source of drinking water of Tehran metropolitan area. In this paper, the environmental geochemistry of water and sediments have been studied. Eight sampling stations were selected in the lake and water samples were taken for measurement of trace elements in dissolved and particulate phases. In addition, sediment samples were taken at the same points by using a grab. The geochemical analysis performed by ICP-OES method showed that the concentration of potentially toxic metals were measured below the detection limit of the instrument and fall in the ranges of safe drinking water guidelines. The sediment samples showed concentrations within the quality guideline values except for As and Pb. The enrichment factor and Igeo were calculated for the sediment samples indicating that the sediments are not contaminated. Metal enrichment in sediments is however very strong compared to water samples and it is suggested that the adsorption processes have important role in sorption of metal contaminants onto the surface of sediment particles and it could be regarded as a potential for contamination if they return to water column in case of change in sediment physicochemical conditions.