The Use of Vetiver Grass Slips in Removing Heavy Metal Contamination of Dumpsite in Ibadan Metropolis

Refuse for different sources are indiscriminately dumped at various sites within Ibadan metropolis. These dumpsites are prone to high levels of contaminants high in toxic substances particularly heavy metals. Heavy metals polluted materials are known to have injurious effects on man's health and livelihood because of the poor waste management system put in place. Experiments were conducted to test the efficiency and efficacy of using Vetiveria nigritana(VN) and Vetiveria zizaniodies(VZ) grass species in removing cadmium(Cd), arsenic(As) and lead(Pb) and improving soil quality of dumpsite. Sixty samples were randomly collected from Bodija market dumpsite at a depth of 0-100cm. Pre-trial composite soil and vetiver slips were analyzed for levels of heavy metal contaminant. The treatments consisted of VZ, VN and a control (without vetiver grass) in pots filled with 5kg of dumpsite and replicated four times in a screen house experiment. There was no difference in the heavy metal absorption sequence of the two vetiver species. Higher amounts of Cd were absorbed by vetiver shoots ). Relative to the initial heavy metal contaminants of the dumpsite soil, the vetiver grasses were able to remove nearly all the Cd in the dumpsite soil (98%) while the absorbed Pb by vetiver grass was about (30%). There was no evidence that As was absorbed from the soil. Vetiver grass reduced the concentration of lead and Cd in the soil below the tolerant level. Hence, would serve as an agent of bioremediation of heavy metal polluted soils