survey of heavy metal (copper, iron, lead, cadmium, zinc and nickel) concentrations and their effects on the water quality of anzali wetland

anzali international wetland is one of the most valuable water resources as registered in ramsar convention with an extent of about 150 km2 in the south caspian sea. this wetland, not only has ecological and biological importance for migratory birds and rare fish species, but also is used for farms to discharge into the caspian sea through this wetland. therefore its pollution control is very important for human life. in this study 6 elements (copper, iron, lead, zinc, cadmium and nickel ) in anzali wetland were analyzed by atomic absorption spectroscopy method. . water samples were collected from ten sampling sites seasonally and the results were compared with each other. the detection limits obtained were 0.016 ng/ml for cadmium, 0.02 ng/ml for copper (cu), lead (pb) and zinc (zn), 0.025 ng/ml for iron (fe) and 0.026 ng/ml for nickel (ni). relative standard deviation (rsd) was 1.7%. the results showed that these heavy metals were present in the water. concentrations of cu (0.6 mg/l) were higher than international standards reported in some stations. this can be due to industries around the wetland. the average level of heavy metals was higher in spring than in the other seasons which can be due to increase in seasonal rainfall and intensity of flow from rivers to wetland.