Research Article
Odokuma LO, Ubogu M
Abstract
The growth and tolerance of Phragmitis ausralies to 0, 1, 3 and 6% w/w crude oil contamination in mangrove swamp soil in the Niger Delta was investigated by stem propagation for 120 days period in a green house set-up. The plant recorded 100 % germination in all crude oil concentrations including control. Germination time was, 5.0, 5.3, 5.3 and 7.0 days for the various concentrations of crude oil respectively. While plant height decreased with increased concentrations of crude oil from 3% and above, increased concentrations did not show significant effects on the root length, leaf area and girth growth of plant (p<0.05). However, while there was no significant difference between 0 (control) and 3%, 1% produced an increase as against 6%, which produced a decrease in the fresh and dry weights of plant (p<0.05). The following hydrocarbon utilizing bacteria and fungi, Pseudomonas aeruginosa, Micrococcus luteus, Klebsiella sp. and , Aspergillus niger, A. flavus, Penicillium oxalicum , Mucor sp respectively, were isolated from the rhizosphere of Phragmitis ausralies with the highest crude oil contamination (6 % w/w) using Oil Mineral Salt Agar (OMSA). The total hydrocarbon utilizing bacterial and fungal counts were 7.1 × 106 ± 4.6 × 105 cfu/g (21.7%) and 4.5 × 105 ± 2.6 × 104 cfu/g (11.2%) respectively. Analysis of the baseline properties of soil sample for plant propagation indicate TPH level of 397.5 mg/kg, TOC, 0.06%, pH,5.05 and porosity, 32.0% . In this study, P. australies grew and survived in all concentrations of crude oil contaminated mangrove swamp soil with a high percentage population of hydrocarbon utilizing bacteria and fungi in its rhizosphere without any form of exogenous stimulation or augmentation, it is therefore a potential candidate for rhizoremediation.