Use of Rubber Ash Enriched Vermi-Compost on Decreasing Cadmium Sorption in Lettuce Plant

Remediation of soils polluted to heavy metals especially in industrial cities is very important in environmental pollution studies. This research was performed to investigate the effect of rubber ash enriched urban waste vermi-compost on decreasing Cadmium (Cd) availability in lettuce plant in Cd-polluted soil. Treatments consisted of applying urban waste vermi-compost (0, 20, and 40 t/ha) enriched with 0 and 200 kg/ha rubber ash in a polluted soil with 0, 20, 30, and 40 mg Cd per kg, and plant in this experiment was lettuce. Soil and plant Cd concentration was measured by atomic absorption spectroscopy (AAS). Findings: Increasing the use of urban waste vermi-compost from 0 to 20 and 40 t/ha in a Cd-polluted soil (20 mg Cd per kg soil) caused a significant decrease in soil Cd availability by 1.3 and 2.4 times, respectively. Cd concentration in plant aerial organ was also decreased by 1.1 and 1.8 times, respectively. Applying 20 and 40 t/ha rubber ash enriched urban waste vermi-compost in a Cd-polluted soil (30 mg Cd/kg soil) caused a significant decrease in Cd concentration of plant aerial organ by 1.2 and 1.9 times, respectively. Applying urban waste vermi-compost causes a decrease in Cd availability in soil and plants and meanwhile, enrichment of this organic compound with rubber ash also decreases Cd sorption by plant