Risk Assessment of Contamination by Heavy Metals in Zanjan of Iran using SAW method

Heavy metals are stable and persistent pollutants of the environment, and can cause both natural and anthropogenic pollution in the environment. Therefore, they are regarded as a serious risk for survival of living organisms. In order to reduce environmental problems of these metals, we need to identify natural and anthropogenic resources of them. Indeed, identifying the risk factors and awareness of the amount and effects of pollutants on the one hand, and accurate ranking of the polluting units on the other are essential steps for proper evaluation and timely and appropriate response to these risks, resulting in reduced damage due to them. The purpose of this study is to identify potential pollution sources of heavy metals of mercury, arsenic, lead, cadmium and chromium in Zanjan Province of Iran and their sampling, in order to present an index for ranking polluting units using appropriate scientific approaches like multi criteria decision making for a more accurate and quantitative assessment of risks and planning response to them in due time. The results of this study indicate that among 26 sites sampled, Mineral Processing Corporation of Iran is the most critical place of environmental risk in Zanjan province.