PhytoremeDiation ofHeavyMetalsContaminated Environments: Screening forNativeAccumulatorPlants inZanjan-Iran

Abstract

Environmental pollution with heavy metals is a global struggle. Phytoremediation is an effectiveand low-cost technology for refinement of polluted soils. This research was conducted in Zanjan province(located in North West Iran) where metallurgical industries are developed quickly. In this study, based on theheavy metals contamination of soil in the studied area six sampling sites were selected taking into account theindustrial distributions as well as the low/high traffic congestions. Leaves from eight tree species namely:Populus nigra, Ulmus pumila, Fraxinus excelsior, Robinia pseudoacacia, Acer hyracanum, Salix alba, Thujaorientalis, and Cupressus sempervirens var arizonica, were sampled and analyzed by ICP-OES (SpectroGenesis) for their heavy metal contents (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb). Results showed that heavymetals in stations close to the lead and zinc smelting industrial complexes are much higher than averageshowing a high correlation with their respective metal concentrations in soils. This clearly indicates that heavymetal contents in tree leaves in the studied area are solely related to industrial activities notably NationalIranian Lead and Zinc (NILZ) as well as Zinc Specialized Industrial Complex (ZSIC) companies. Based on theresults, the studied native plants accumulate different metals selectively and Populus nigra was found to bethe best accumulator plant for Mn, Zn and Cd, Thuja orientalis, as the best phytoextractor for Fe, andCupressus sempervirens var arizonica is the best species among the studied native plants for accumulation ofPb.