Trace metal levels in soils and vegetation from some tin mining areas in Nigeria

Abstract

Samples of soil and vegetation from some tin mining areas of Nigeria were analysed for lead, zinc, copper and cadmium content. The levels of Pb and Zn were found to be high in some samples. The mean levels of metal in the vegetation were: 86.6+ 36.0, 49.6+ 28.3, 12.6+4.8 and 1.4+0.8 µgg-1 dry weight for Pb, Zn, Cu and Cd respectively whilst those in the soil were 736+120, 690+ 216, 43+ 18 and 18+12 µgg-1 dry weight for Pb, Zn, Cu and Cd respectively. The variability of metal levels in the area indicates that in addition to mining, other anthropogenic sources of metal contribute significantly to metal levels in the area. The EDTA – extractable metal fractions suggest that trace metals are being mobilised in the soil and made available to crops. The metal levels in the vegetation samples were higher than those recorded for areas of low atmospheric metal pollution in Nigeria with no identifiable sources. Although, there have been no cases of recorded metal toxicity in the area, there is the need to regulate and control mining wastes in order to prevent the effects of metal pollution in the area.


Key words: metals, environmental samples, mining areas.


[Global Jnl Pure & Appl. Sci. Vol.9(3) 2003: 331-338]