| Abstract: | The role of the Conocarpus lancifolius tree in remediaitng oil-contaminated soil, which was bioremediated using conventional methods, was investigated. The selected tree was used to phytoremediate bioremediated oil-contaminated soil for three successive growing seasons. At the end of the phytoremediation experiment, 85.7% of measurable total petroleum hydrocarbon (TPH) was degraded in Conocarpus lancifolius rhizosphere, and the detectable concentrations of some poly aromatic hydrocarbons (PAHs) were less than 0.02 ppm. A number of hydrocarbon degrading microorganisms (HDMs) were isolated at 35°C under aerobic conditions, and were identified using 16S rRNA gene sequencing and fatty acid methyl ester (FAME) analysis. The efficiency of the isolated HDMs in degrading a mixture of hydrocarbon compounds (HC) was assessed. Among the bacterial isolates, Rhodococcus equi was distinguished from the other isolates because of its efficient degradation of some compounds in the HC mixture. Samples were also collected from Conocarpus lancifolius vegetative parts and were analyzed for heavy metal and mineral accumulation. The results demonstrated that the Conocarpus lancifolius tree was able to uptake high levels of chromium (Cr), vanadium (V), and nickel (Ni) and accumulate them in the tree's roots. Additionally, Conocarpus trees tolerated high concentration and accumulated several metals in all plant tissues. These metals included aluminum (Al), calcium (Ca) and iron (Fe). |
