Phytoaccumulation potentials of three indigenous plant species grown in used engine oil polluted soil.

Abstract

The study was carried out to investigate the potentials of Chromolaena odorata, Aspillia africana, and Axonopus compressus in the remediation of used motor oil contaminated soil. An equal volume of soil was spiked with 20% (w/w) of used motor oil and monitored for 90 days. The test plants were harvested after 90 days and analyzed for the presence of heavy metals using AAS. Results obtained revealed that variable concentrations of heavy metals and TPH were accumulated by the test plants from the contaminated soil and were stored in the root, shoot and leaf. Metal accumulation patterns were in the order: C. odorat>A. africana>A. compressus. C. odorata and A. africana exhibited characteristics typical of a phytoextractor while A. compressus could be applied as a phytostabiliser of spent engine oil-polluted soils. The result further showed that TPH content of C. odorata accumulated the highest level of TPH (178.43 mg/kg) in the leaf followed by A. compressus (46.58 mg/kg) and A. africana (26.26 mg/kg). Thus, Chromolaena odorata, Aspillia africana, and Axonopus compressus possess hyper-accumulative uptake capacity for bioavailable residual heavy metals and TPH therefore could be suitable for and applied in the phytoremediation of spent engine oil contaminated Agricultural soils in the tropics.