Evaluation of Potential Toxic Metals Accumulation in Wheat Irrigated with Wastewater.

ABSTRACT

The present study was carried out to ascertain the level of various metals in wheat variety (Chagi-4) irrigated with diverse doses of wastewater. The concentration of metals in soil, water and wheat grain samples was examined through an atomic absorption spectrophotometer. In wheat grains, the mean values of metals (mg/kg) varied from 0.06 to 0.2 for Pb, 1.2 to 1.6 for Cd, 0.6 to 0.9 for Ni, 0.8 to 1.6 for Fe, 0.4 to 1.0 for Mn, 0.7 to 1.4 for Cu, 0.3 to 0.5 for Cr, 0.1 to 0.9 for Zn and 0.03 to 0.2 for Co, correspondingly. Measured concentrations were found within the permissible limit given by FAO/WHO except for cadmium whose concentration exceeded an acceptable limit 0.2 mg/kg suggested by FAO/WHO. It might be due to high soil pH, which hinders the efficient transfer of metals between different mediums. Wastewater irrigated soil, wheat and water had high metal values, but the low rate of transfer was noticed from soil to grains. Higher bioconcentration factor was obtained for manganese and cadmium; cadmium had even higher pollution load index, which could indicate the contamination status of soil. Therefore, regular monitoring of wastewater is necessary to prevent the excessive build-up of metals.