Bio-Availability of Heavy Metals in Wild Plants Found in an Abandoned Battery Waste Site

Abstract

This study examined the concentration of trace metals in the soil of an abandoned slag dumpsite, and the corresponding levels of these metals in the tissue of wild plants growing on such sites. For this purpose, soil and wild plant species were collected from Lalupon village in Oyo State, Nigeria. The sample extracts were analyzed for metals such as Lead (Pb), Cadmium (Cd), Nickel (Ni) and Chromium (Cr), using an atomic absorption spectrometer (Buck 210 VGA model).The level of correlation between each metal absorbed by the plant part, and the contaminated soil showed a positive correlation. A t-test showed that each trace metal was significantly different. Plants absorbed the different metals from the contaminated soil in various proportions. The rate of bioaccumulation of these metals showed that each metal had a higher concentration in the root of the plant compared to the shoot. Plant species like Sporobolus pyramidalis, Pycerus polystachyos, Andropogon tectonium and Calapogonium mucunoides showed bioaccumulation of these metals in their plant parts. The analysis revealed that these plant species have the ability to take up and accumulate metals in their roots and shoots. Therefore, these plant species could be assessed for phyto-remediation of metals from contaminated soils. The existence of these metals in high concentrations in the soil is hazardous to humans and animals, if they are established in the food chain.