Abstract:

This study investigated the potentials of Digitaria horizontalis, Eleucine indica and Sataria barbata grass species in the phytoremediation of waste engine oil contaminated soils. Waste engine oil was added to 4kg different soil samples to obtain different concentrations on weight basis: 0% (control), 2%, 4%, 7% and 10% v/w oil-in-soil and allowed to stand for seven days before transplanting. The plants were harvested after 8 weeks of transplanting. Dried plants parts and the soil samples were analyzed for heavy metals (Pb, Zn, Cu and Ni). The results obtained showed that there was increased percentage reduction of heavy metals in the soils. D. horizontalis recorded the maximum reduction for Pb and Ni to 99.79% level, E. indica recorded maximum reduction of 99.98% for Ni while S. barbata recorded 99.9% reduction for Ni. Percentage reduction increased as the concentrations of the waste engine oil increased. In conclusion, the three-grass species studied possessed phytoextraction potentials for phytoremediation of waste engine oil contaminated soil.