Assessment of Some Plant Species for Possible Heavy Metal Uptake in Some Dump Sites in Ogbomoso Metropolis.

Abstract

Metal concentration [Pb,Cd, Cu, and Mn] were measured in nine plant species and soil samples from one non-contaminated site and twelve dump sites located in Ogbomoso city, Nigeria. One dominant plant spicies was collected in paper envelope at each site. Soil sample were also collected in polythenes bags with plastic spoon up to 15cm depth at three spots per site, mixed together to prepare a composite sample. The entire soil plant samples were taken to the laboratory at IAR&T,Moor plantation, Ibadan for analysis. The plant samples were washed with de-ionised water, dried in the oven at 70C to constant weight, and ground with hammer mill incorporated with 2mm sieve.2g were weighed into crucible and ashed at 58oC. The ash was the washed with di-ionised water. Soil samples were drried, sieved with 2mm sieve and 2g was weighred into digestion tube and digestion procedure followed using 10ml concentrated perchloric acid and nitric acid [1:1]. Organic carbon percentages and PH of the soil samples were determined. The absolute metal concentration from the polluted soil ranged from the lowest Cr [990g/g] to Cu [24,200pg/g] with the trend Cr<Pb<Cd<Mn<Cu. Five plan species. Tithonia diversifolia., Ageratun conyzoides, Cassia obtusifolia, Trriumfetta rhomboids, and Sida corymbosa were found to be good bioindicator of metal pollution and can be suitable forr phyoremediation of metal polluted site. The implication of some of these plant species in natural food chain werre also disussed.