Assessment of geochemical and distribution of heavy metals Pb, Cu, Zn and Ni in the Aras free trade-industrial zone

Aras river due to located in the path of mining activities and having special ecological, economic, social and a variety of different species of aquatic plants and animals is very important and assessment of its quality is essential. This study was conducted to assess pollution of Pb, Cu, Zn and Ni in the Aras free trade-industrial zone. Samples of sediments, water, plant (Typha australis) and fish (Varicorhinus dapoeta) were collected in four sampling sites of 150 km of Aras river in autumn 2013 and summer 2014. The results indicated that the concentration of all elements in water and fish samples aligned with standards, although Cu value exceeded standard level within sedimentation and plant. According to contaminant criteria (contaminant factor, pollution load index, and geoaccumulation index), Cu concentration was very high in all sampling sites except SantSpataneous site. Its reason is likely to overloading Cu from Sungon mine. The magnitude of heavy metal pollutants in all sampling sites was identified as follows: Cu > Zn > Pb = Ni. The bioaccumulation factor of heavy metals in fish samples was found to be lower than 1 indicating they probably were uptaked through fish respiratory and dermal surfaces rather than dietary uptake. The high concentrations of Pb and Zn in Typha australis from Ilganeh river and Gholan and Missen sites exhibited that this species could be utilised to remediate the polluted places to heavy metals.