Effect of urban wastewater on forage maize in south of Tehran

ABSTRACT: This study was carried out in order to study the effects of wastewater irrigation on heavy metals accumulation in forage corn in south of Tehran. Experiment design was randomized complete block design with four treatments and three replications. Treatments included pure water (control), wastewater and combination of water with wastewater. Results of the experiments indicated that effect of treatments on accumulations of Pb-Ni and Cu-Zn were significant at %1 and %5 levels, respectively, while there was no significant difference among treatments in respect of macronutrient accumulation such as nitrogen, phosphorous and potassium in different part of corn. Accumulation of elements in corn organs indicate that greatest accumulations of heavy metals except Cd were in roots and for macro elements in grains. Comparison of means using Duncan tests in corn organs indicated there were significant differences in Cu, Cd, Cr, Pb, Zn, Ni in roots, Zn in stalk and P, K in grains, but there was no significant difference among treatments in leaves. Accumulation of Pb in treated corn plants with wastewater was more than 10mg/kg and reached to phototoxic levels for animal feeding. With attention to hazardous effects of Pb on humans and animals this is necessary to settle legal restrictions and limitation to use of municipal sewage and wastewater for irrigation in forage corn in south of Tehran. Since accumulation of Cd and Ni in grains of forage corn under wastewater irrigation are more than normal conditions and reaches to toxin level, it is necessary to self restraint use of ear as human fresh food.