Investigation of Heavy Metals Concentration in Wastewater Reused for Agriculture Irrigation in Isfahan

Background & Aims of the Study: The use of urban wastewater in agriculture is receiving renewed attention with the increasing scarcity of freshwater resources in many arid and semiarid areas, despite its associated health and environmental risks. Long term wastewater usage for irrigation results in accumulation of heavy metal in soils and plants. So, due to the environmental and health risks associated with wastewater irrigation, this study was carried out to investigate heavy metals in the Wastewater Treatment Plant effluent in Isfahan. Materials & Methods: A duplicate sample of treated wastewater was taken from Isfahanʹs North wastewater treatment plant (WWTP) in winter season. Then, examination was accomplished according to Standard Methods for the Examination of Water and Wastewater. Results compared with Iran standard for wastewater reuse in irrigation. Results: In this study, there was no cadmium (Cd) and chromium (Cr) in the effluent, and the mean concentration of lead (Pb), nickel (Ni), zinc (Zn) and copper (Cu) content was 0.008 and 0.004, 0.028 and 0.018 mg/L, respectively. The Iranian standard content of Cd, Cr, Pb, Ni, Zn, and Cu for irrigation are 0.05, 1, 1, 2, 2 and 0.2 mg/L. Conclusions: The results of this study indicate that the mean contents of Cd, Cr, Pb, Ni, Zn, and Cu in the effluent of Isfahan North WWTP was in safe range for use in agricultural irrigation. All of them were lower than the allowable limit suggested by the standard of Iran.