efficiency of vermiremediation in reducing level of heavy element in pollution soils containing crude oil

This study aims to treat heavy elements pollution in soils polluted with crude oil near the southern refineries in the shuaiba area in basrah governorate in an environmentally friendly way by using the earthworm lumbricus terrestris and testing its efficiency in treating heavy elements pollution, this process is known as bioremediation (vermiemediation(, four different concentrations of pollution were made (1%, 2%, 5%, and 8%). the worms were raised in these different concentrations of pollution for 40 days, where some heavy elements such as lead, nickel, cadmium, and copper were measured and examined every ten days. the results showed that the highest treatment efficiency for lead was 93% after 40 days of treatment at a pollution concentration of 1%, and the lowest treatment efficiency was 9% after 10 days of treatment at a pollution concentration of 8%. the nickel treatment efficiency was highest at 99% after 40 days of treatment at a pollution concentration of 1%-2%, respectively, and the lowest efficiency was 8.5% after 10 days of treatment at a pollution concentration of 5%, while the highest treatment efficiency for cadmium was 100% after 30-40 days of treatment at a pollution concentration of 1-2%, respectively, and the lowest efficiency was 51% after 10 days of treatment at a pollution concentration of 8%  ,the highest efficiency for treating copper was 99.9% after 40 days of treatment at a pollution concentration of 1%-2%, respectively, and the lowest treatment efficiency was 21% after 10 days of treatment at a pollution concentration of 8%. the results showed the high efficiency of the earthworm lumbricus terrestris in treating soils polluted with heavy elements.