Uptake Of Zinc, Copper And Nickel on Spent Oil Contaminated By CyanthiUiam cinereum (Little Iron Weed):- Ugwu, Juliana I

ABSTRACT xii The effect of waste oil on soil has caught much interest in recent research. The use of pig dung as alternative compost manure has also been studied by some researchers. The aim of the present study is to ascertain the rate of heavy metal (Zinc, Copper and Nickel) pollution caused by spent oil and pig dung on soil and the rate of uptake of such heavy metals by Cyanthillium cinereum (Little Ironweed). We hypothesized that if the rate of metal uptake by Cyanthillium cinereum was high, it could offer hope of being used in phytoremedation of Zn, Cu and Ni contaminated soil. The study was performed using Cyanthillium cinereum planted on normal soil, spent oil contaminated soil and pig dung treated soil. The plants were collected and tested for Zn, Cu and Ni concentrations using Atomic Absorption Spectrophotometer (AAS). The pH was also measured using pH meter and the Bioconcentration Factor (BCF) and Extraction Coefficient (EC) were calculated. The results obtained showed that there was a significant increase (P<0.05) in the concentrations of Zn, Cu and Ni in the spent oil and pig dung treated soils compared to the normal soil and plants grown on the treated soils had higher extraction coefficients of such metals. Soil pH was lowest for uncontaminated soil, increased for pig dung contaminated soil and more increased for spent oil contaminated soil. Mean cation exchange capacity increased significantly (P<0.05) when spent oil was added to soil from contaminated site and reduced significantly when pig dung was applied. These results support the claims that deposition of spent oil and use of pig dung as manure could pose some heavy metal toxicity effect on the soil used for farming and that Cyanthillium cinereum could uptake some of these metals. These findings may be useful in the search for agents to be used in phytoremediation of Zn, Cu and Ni contaminated soil as Cyanthillium cinereum could be useful as one ofsuch agents.