Impacts of vermicompost on heavy metals accumulation in plant and soil

The present study was conducted to investigate the effect of vermicompost on heavy metals accumulation in plants and soil irrigated with contaminated water at the Campus of the Faculty of Agriculture and Natural Resources of Razi University. The research was carried out in two treatments, using vermicompost and no vermicompost (control) in three replications on the accumulation of copper, iron, zinc, cadmium and manganese in roots, shoots and fruits of tomato and okra plants as well as in two soil layers (0-30 and 30-60 cm). The results indicated that vermicompost application significantly increased the amount of metals in most parts of tomato (fruit: Cu 10.1 , Fe -11.86 , Mn 5.97 ; leaves: Fe 8.4 , Zn 9.73 , Mn 2.97 ; root: Mn - 5.56 ) and okra (fruit: Cu 6.73 , Fe 9.98 , Zn -7.18 , Mn 3.06 ; leaves: Fe 9.51 , Zn 6.63 , Mn 3.84 ; root: Cu -9.7 , Fe -10.2 , Zn - 14 , Mn -7.12 ). Although vermicompost treatment increased the amount of metals in the soil but it was not significant and only in the first layer the Zn 6.33 showed a significant increase. Also, vermicompost prevented moving of metals into the soil. Therefore, simultaneous use of vermicompost and irrigation with contaminated water is not recommended due to increase in heavy metals content in different parts of the studied plants and soil.