Effect of Municipal Waste Water Irrigation on Heavy Metal Accumulation in Wheat (Case Study: Shahre Rey Fields)

Declining water resources caused usage of recycled water that sometimes not purified well.  The growing population and consequently increasing water demand, along with a shortage of available freshwater resources have inevitably led to the use of unconventional water resources. Irrigation lands with urban wastewater requires quality and quantity control for achieving food security. Therefore, the present study was conducted to investigate the effects of irrigation with urban wastewater on the concentration of Nickel and Cadmium in soils and their effects on plant, root, shoot, and functional characteristics of wheat.

  Field sampling was carried out at random from a depth of 0 to 20 cm. Wheat samples were taken at harvest from a 1-meter by 1-meter area. A total of 20 samples for Cadmium metal and 20 samples of Nickel metal were taken.

The results showed that the average concentration of Cadmium and Nickel was 10.6 and 49.43 kg, respectively, which resulted in an accumulation in various parts of the wheat plant. Increasing the concentration of Cadmium and Nickel in the soil increases the accumulation in the root, upper parts, and wheat seeds. Also, increasing the concentration of Cadmium and Nickel in the soil decreases the dry weight of the root, the shoot, and the weight of the thousand seed. However, there was no significant effect on two traits, number of grains per spike and number of spikes per square meter. The effect of Cadmium concentration was higher than that of Nickel.

Increasing 1 mg of soil Cadmium caused increasing, 0.81, 0.56, 0.6 mg Cadmium in root, upper parts and seed. For Nickel increasing the soil concentrations caused 0.29, 0.29, 0.11 mg in root, upper parts and seed.