Investigation of Heavy Metals Content in Sediments of Shirin Su Wetland, Western Iran

Shirin Su Wetland ecosystem, Hamedan Province, western Iran, has a great biodiversity and aesthetic. The distribution and accumulation of heavy metals: Cd, Cr, Cu, Fe, Pb and Zn in sediments were assessed from this wetland in February to May of 2013. The chemical speciation of elements was determined using mixed acid digestion. The results showed that the mean concentrations of metals (microgram per gram dry weight) in sediment samples were: 0.16 for Cd, 23.07 for Cr, 10.62 for Cu, 689.82 for Fe, 27.9 for Pb, 5.01 for Zn. Furthermore the mean concentrations of all metals except Fe in all sediment samples were lower than Threshold Effect Concentration and there are not adverse effects. According to I-geo values, in most stations the sediments quality was classified in unpolluted category. In addition, the sediment samples from station 2 and station 4 accumulated the minimum and maximum mean concentration of metals, respectively. Pearson correlation indicates that the anthropogenic sources of Zn, Fe and Cr are closely related in the sediment from Shirin Su Wetland.