Pollutants remain in sediments for a long time and can be reflect the history of contamination of aquatic ecosystem due to their roles as both carrier and deposition of heavy metals. Thus, assessment of sediment quality is essential to identify and management of potential stresses. The aim of this study therfore, is to determine the heavy metals concentrations in Gavkhouny wetland sediments and risk assessment of these heavy matals. In this study, 30 surface sediment samples (0-20 cm) were taken from Gavkhoni wetland delta. The concentration of Pb, Ni and Cd were analyzed after the digestion of samples. The samplewere alsoexamined tomeasuretheir physiochemicalcharacteristics (such as pH, EC and organic matter). We used Hakanson ecological risk assessment method and modified potential ecological risk index (MRI) were used to evaluate the potential risk of heavy metals. Kiriging method also used for zoning of wetland based on heavy metal ecological risk index.According to the results, the maximum amount of MRI and RI were observed in the southern and eastern of delta wetland, due to stagnant water of wetland, less vegetation of these regions, high clay content, low EC content, low percentage of lime and organic matter. and . pond water as in these two areas was stagnant pond water and no vegetation and also based on the physicochemical characteristics of sediments ,was. In the Zoning of Four wetland areas, MRI results were better than RI, becaue MRI with regard to the physicochemical characteristics of soil, can better show the environmental risk of heavy metals. Also in this study, by using Monte Carlo simulation that shows uncertainty, the results of the risk assessment of heavy metals by the Hakansvn method was repeated in the range of 3,000 to 5,000 times and thereby was Obtained percent predicted probability of risk Also about the possibility of potential risk for individual heavy metal (Er i ), the possibility of risk of lead and Nickel respectively are 75 and 57 percent at low risk keywords: Gavkhouni Wetland, Sediments, Heavy metals, Ecological risk assessment, Interpolation, Monte Carlo simulation method
