Abstract

This study was proposed to assess the suitability of washing technique to distinguish between airborne and soil borne several metal contaminants. For this reason, six plant species which grew under Mobarakeh Steel Company emissions were selected. Aluminum, iron, nickel, manganese, zinc, copper and lead concentrations were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) in washed and unwashed leaves of plants. The water washing reduced Al, Fe and Ni concentrations significantly (p < 0.05 and 0.01) in the most species. The highest reduction percentage of three metals was observed in Nerium oleander which was 76, 84 and 69% for Al, Fe and Ni, respectively. Washing had no significant effect for removing Mn, Zn and Cu from the leaf surfaces of most species. Influence of washing procedure on Pb concentrations was different. Washing effect varied with various physico-chemical characters of contaminants, plant species, primary level of contaminants and washing time. The results of this study show that the use ofdistilled water is a good technique for removing atmospheric deposition of Al, Fe and Ni from plant leaves. Also, there were a significant positive correlation between Al, Fe, Ni and Zn which had anthropogenic source.

Key words: Contaminants, airborne, soil borne, water washing, leaves, heavy metals, tree, shrub, washing effect.