Effect of sulfur granular MSW, foliar application of iron sulfate on bio-degradation of diesel oil in a Cd-polluted soil in the presence of Thiobacillus bacteria

Background: Remediation of petroleum hydrocarbons from soil is one of the important factors. This research was done to investigate the effect of sulfur granular municipal soil waste (sulfur granular MSW), foliar application of iron sulfate on bio-degradation of diesel oil in a Cd-polluted soil in the presence of Thiobacillus bacteria. Methods: Treatments consisted of applying sulfur granular MSW at the rates of 0 and 15 t/ha, foliar application of iron sulfate (0 and 500 mg/l) in a Cd-polluted (0, 10 and 20 mg Cd/kg) soil that simultaneously contaminated with diesel oil (0,4 and 8 %(W/W)) in the presence of Thiobacillus bacteria. After 60 days, the corns were harvested and the plant Fe and Cd concentration was measured using atomic absorption spectroscopy (AAS). In addition, the bio-degradation of diesel oil in the soil was also measured. Results: Soil application of sulfur granular MSW (15 t/ha) significantly increased the bio-degradation of diesel oil in the soil by 16.1%. However, soil pollution with Cd had adverse effect on bio-degradation of diesel oil in the soil. The presence of Thiobacillus bacteria had significant effect on increasing and decreasing the plant Fe and Cd concentration by 16.1 and 17.3%, respectively. Conclusion: Based on the results of this study, using sulfur granular MSW and foliar application of iron sulfate has significant effect on bio-degradation of diesel oil in the soil in the heavy metal polluted soil. However, the role of plant physiology, the type and amount of pollution on phytoremediation efficiency cannot be ignored.