Phytoremediation Innovative Technology (Series 2): A Short-term Comparative Analysis of Enhanced Biodegradation of Crude Oil in the Soil by Macrophytic Nodulation

A short term comparative ecological study of the use of two agro-forestry species, Leucaena leucocephala , Lam De. Wit and Bauhinia monandra , Kurz, in bioremediation of oil polluted environment was carried out, focusing on the evaluation and enhancing potential of the macrophytic species for degradation of hydrocarbon (crude oil) in the soil relative to their nodulation efficacy. Results show that L. leucocephala had nodules with levels ranging between 1.40 ± 1.40 to 11.60 ± 2.20 plant -1 and relative to various pollution levels and 15.10 ± 6.10 plant -1 in the control condition. Though L. leucocephala experienced pollution depression upon time lag in nodulation, the depression was directly proportional to the intensities of pollution. Bauhinia monandra had none at the end of the experiment both in the polluted and controlled conditions. Total hydrocarbon level following treatment of the soil by L. leucocephala and B. monadra has been deduced in relation to post-pollution concentration, disappearance and net % loss on such treated soil environment. A comparatively high value of 60% total loss of crude oil was indicated in L. leucocephala treated soil. This shows that natural biodegradation could be a major and ultimate mechanism for elimination of oil in terrestrial environment. The highest total % loss of crude oil was recorded in Leucaena leucocephala than Bauhinia monandra treated soil. Leucaena leucocephala showed an enhanced performance than Bauhinia monandra at the end of the study. Leucaena leucocephala was thus considered more ideal and more promising for remediation work than B.monandra . Keywords : Leucaena leucocephala, Bauhinia monandra , bioremediation, crude oil, nodulation Global Journal of Environmental Sciences Vol.4(1) 2005: 11-18