Heavy metals accumulation by talinum triangulare grown on waste dumpsites in Uyo Metropolis, Akwa Ibom State, Nigeria

Abstract

The accumulation of some heavy metals by Talinum triangulare grown on waste dumpsites in Uyo Metropolis was studied using atomic absorption spectrophotometer. Results obtained indicated the following ranges for the metals in dumpsite soil: Cd: 1,85-8.65 mg kg-1; Pb: 42.05-60.85 mg kg-1; Ni: 11.05-20.55 mg kg-1; Fe: 183.00-237.20 mg kg-1 and Zn: 11.35-119.30 mg kg-1, while the ranges in Talinum triangure were Cd: 0.10-0.30 mg kg-1; Pb: 0.33-1.55 mg kg-1; Ni:0.05-0.45 mg kg-1; Fe: 223.43-260.00 mg kg-1 and Zn: 2.20-29.95 mg kg-1. These results indicated higher levels of the metals in soils and plants from dumpsites than the values recorded in the Control samples. In the dumpsite soil and plant samples, Fe recorded the highest mean concentrations in both samples while Cd and Ni concentrations were the lowest in soil and plant respectively. Although, the ranges obtained for the metals in plant and soil were within the recommended limits except for Cd in soil and Fe in plant, it maybe risky to consume water leaf grown on dumpsites since it can accumulate much of these toxic metals. The results obtained also revealed that apart from Cd, the concentrations of other metals analyzed for in plant and soil correlated positively at p = 0,05. The transfer Ratio between dumpsite soil and plant samples indicated the following trend: Fe>Zn>Cd>Pb>Ni showing that the rate of metal uptake by T. triangulare was greatest with Fe, while the rate of Ni uptake was the least. Relative standard deviations in the distribution of the metals in plant and soil samples from one dumpsite to the other were also studied; results obtained showed a high degree of variability in the distributions of the metals in both samples with the locations. © 2007 Asian Network for Scientific Information.