Accumulation of Zn, Cu, Pb and Ni in Soil and Different Parts of Plane Tree (Platanus orientalis L.) Seedling Following Irrigation with Water Treatment Effluent

In order to assess the effect of water treatment effluent irrigation on heavy metals accumulation in soil and seedling different part, a case study was undertaken at the site near to the Eastern Tehran water treatment plant in which seedling were implanted in three score rows and were irrigated with water treatment effluent, well water and mix water (50% well water 50% water treatment effluent) from April 2010 to October 2010. Three replications were considered for each of three score rows. The concentrations of Zn,Cu, Pb and Ni were measured in the soil, Roots, stems and leaves of plane tree seedling with selection three randomize samples from each treatment in periodic form (in each two month one time) to the end of growth season. Samples of irrigation water, soil and seedling parts were analyzed for mentioned heavy metals. Results indicated that water treatment effluent had higher concentration of Zn ,Cu, Pb and Ni compared to well water and the concentration of Pb and Ni of water treatment effluent were greater than the normal range. Irrigation with water treatment effluent increased Zn ,Cu, Pb and Ni in soil compared to well water. The mean heavy metal concentrations in topsoil were higher than the standard (FAO) for all heavy metals except Cu. Zn and Cu concentration in leaves of seedlings irrigated with water treatment effluent were significantly greater than those in well water but the concentration of Zn and Cu in leaves were below the permissible limits of the standard. Neither Pb nor Ni was detected in seedlings parts. Based on these results, it can be concluded that proper management of water treatment effluent irrigation and periodic monitoring of soil fertility and quality parameters are required to ensure successful, safe and long term reuse of effluent for irrigation.