A.Gray, a pan-tropic invasive weed species, cleanup spent lubricating oil polluted soil? A.Gray, a pan-tropic invasive weed species, cleanup spent lubricating oil polluted soil?

Two pot trial were conducted in the crop garden of the department of crop protection and environmental biology, university of Ibadan between march and june 2005, to evaluate the phytoremedating potential of tithonia diversifolia in spent oil polluted soil to enhance the agricultural productivity. The study was a completely randomized design with three replicates. Varying pollution levels were created by administering spent lubricating oil at 0,50,100,150 and 200ml per 4kg soil pots. Two tithonia seedling were transplanted into each pot and were monitored for 12 weeks. At commencement of two trials, lead concentrations in the soil averaged 3.78 mg/kg and 2.05mgkg in the control and in 200-ml treatment respectively, and cadmium concentrations averaged 0.73mg/kg and 2.05mg/kg in the control and 200-ml treatment respectively. At the end of the two trials, lead content was reduced to 0.00 and 11.88mg/kg and cadmium content was reduced to 0.00 and .43mg/kg in the control and 200-ml treatments respectively. The result showed that tithonia seedlings were able to absorb lead and cadmium in the shoot compared to the root were about 54% and 30% respectively. The results highlighted further the quality of vegetable produced at urban and peri-urban roadside and wetland gardens