Heavy metals concentrations in <i>Imbrasia belina</i> (phane caterpillar) around the Selebi Phikwe Ni-Cu mine and smelter/concentrator plant, Botswana

Abstract

Samples of Imbrasia belina (phane caterpillar) obtained from around the Selebi Phikwe Ni-Cu mine and smelter/concentrator plant, Botswana were investigated for their heavy metals concentrations. The samples were obtained from 10 sampling sites, which included a chosen control site located 56 km from Selebi Phikwe. Chemical analyses for Cd, Co, Cr, Cu, Fe, Ni, Se and Zn concentrations in the samples of Imbrasia belina were measured using atomic absorption spectrometry. Concentration values obtained for heavy metals in Imbrasia belina were as follows: Cd was between 0.01 ppm and 0.05 ppm, Co was between 0.01 ppm and 0.6 ppm, Cr was between 0.03 ppm and 1.03 ppm, Cu was between 1.3 ppm and 9.79 ppm, Fe was between 1 ppm and 13.5 ppm, Ni was between 1.2 ppm and 4.20 ppm, Se was between 0.01 ppm and 0.03 ppm, and Zn was between 0.6 ppm and 5.79 ppm. The correlation coefficients between heavy metals in Imbrasia belina were generally average. Strong correlations included Fe/Cu, Ni/Cr, Se/Co, Zn/Cu and Zn/Ni. The lowest correlation coefficient was at 0.03 with Ni/Fe. The worms close to the plant; more specifically sites four, five and six were the most contaminated. Results from this baseline study calls for the need to further investigate the possible effects on human health due to the consumption of Imbrasia belina.

Keywords: heavy metals, Imbrasia belina, concentrations, linear trend, nickel-copper

Global Journal of Pure and Applied Sciences Vol. 11(4) 2005: 553-559