Rivers are the water resources to provide the largest water demand in different sectors (drinking water, industry and agriculture, ...), then the evaluation parameters of water quality is very important in the management of water resources. Heavy metals are the most important pollutants in surface water resources. The presence of heavy metals in rivers due to discharge of municipal, industrial and agricultural wastewater may lead to the presence of heavy metals in plants, animals and finally in the human food chain. One of the objective of this study was the investigation of heavy metals in sediments of the Zayandehroud river bed. Therefore, samples of sediments along the upstream of Zayandehroud river bed were taken for three consecutive months at four sampling stations (Zayandehroud regulator dam, Zamankhan Bridge, kalleh Bridge and Nekouabad dam ), and analyzed for the availability of Pb, Cu, Cd, Co, Cr and Ni metals by atomic absorption. In addition, the organic carbon in bed river sediment samples and some parameters of water quality (temperature, pH, EC, DO and suspended solids) were measured by standard methods. The results indicate that the maximum amount of heavy metals is linked to Ni in Zamankhan stationan Bridge and the minimum is related to Cd. The average of heavy metals in bed sediments at the different stations are as follows: i Pb Cr Cu Co Cd Zayandehroud regulator dam: Ni Cr Cu Pb Co Cd Zamankhan Bridge: Ni Cr Cu Pb Co Cd kalleh Bridge: Pb Ni Cr Cu Co Cd Nekouabad dam: There is also a strong correlation between Pb concentration and organic carbon in bed sediments. Various water quality index (WQI) used to measure the quality of surface waters including standard diagrams of water quality index, subjective water quality index and Canadian water quality index. The indices of water quality were determined from upstream to downstream in nine stations (Zayandehroud regulator dam, Zamankhan Bridge, Cham Aseman, kalleh Bridge, Dizicheh, Leng, Mousian, Choum Bridge and Varzaneh. The results indicate that the amounts of these three indices decreased from upstream to Key words: Zayendehroud, Heavy Metals, Bed Sediment, Water Quality Index, MIKE 11
