The relationship between the concentration of heavy metals (lead and cadmium) in soil and seeds of wheat and risk assessment of consumption of wheat

In Asyabk Zarandieh town, located in Central Province, sewage discharge is released within 20 meter from arable land of wheat. This research is to determine the concentration of lead and cadmium in contaminated soils, sewage, irrigation water and wheat grown in the area around the town Asyabk and the correlation between them and assessing the potential risks arising from the consumption of wheat grown in the region.

The sampling of drainage and irrigation water, surface soil, wheat was done by random. Lead and cadmium concentrations in all samples were measured. The results were statistically analyzed. Also the zonation map was prepared by GIS software.

Concentration of lead and cadmium in soil samples obtained less than limit permissible but concentration of Cd and pb in wheat obtained exceeded the national standard of Iran. Based on the correlation results between the amount of   lead and cadmium in the wheat samples, soil and irrigation water, there was a strong positive correlation. While there was no relationship between the concentrations of these elements in the wheat samples and the amount of metals in the wastewater samples.

The lack of correlation between the concentration of lead and cadmium in wheat and wastewater showed sewage spread in the region unaffected in the process of increasing the concentration of lead and cadmium in wheat. The main reason of increase Pb and Cd in wheat samples is related to irrigation water (well water). The risk index (HQ) of wheat consumption in the region obtained smaller than 1 for lead and cadmium.