ABSTRACT

 Trace metal levels of soils and cassava leaves around Ishiagu rock mining site were investigated. Samples of soils (0-10 cm) and cassava leaves were collected at distances from the rock-mining site. A location far from the mining site was taken as the control. The physico-chemical properties of the soils and the trace metal content of both the soils and cassava leaves were determined. The physico-chemical parameters of the soils investigated were sand (42.18-48.54%), silt (42.72 -50.23%), clay (6.58 - 9.10%), pH (5.89 - 6.14), organic matter (1.03 -1.56%), effective cation exchange capacity (4.65 - 6.35) cmolkg* and percentage base saturation (90.52 - 93.91). Result showed that there was no significant difference (P>0.05) with respect to sampling positions on the selected physico-chemical properties of the soils investigated. Levels of trace metals in the soils studied were Pb (4.93 -21.99), Fe (1878.1 - 2062.8), Cu (80.93 - 92.16), Zn (20.39 - 23.34), Cd (1.56 - 7.18) and As (4.61 - 6.72) mg/kg. The concentrations of trace metals in the soils nearest to the mining site were significantly higher (P<0.05) than the concentrations of trace metals in the soils at the control. Levels of total trace metals in the cassava leaves were Pb (1.71 - 7.28), Fe (58.8 - 128.6), Cu (6.48 - 12.87), Zn (1.63 - 3.63), Cd (4.1 - 8.20) and As (1.22 - 12.1 l)mg/kg. The highest concentrations of these trace metals in the cassava leaves were found at sampling positions nearest to the mining site. Correlation studies showed that Pb has a positive relationship with Fe (0.606), Zn (0.472), Cd (0.945) and As (0.574) Cu positively correlated with Zn (0.571) and Cd (0.461). Zn correlated positively with all the trace metals except As whereas Cd has a positive relationship with all the trace metals. Clay content correlated with Cu (0.523) and Zn (0.453) whereas pH and silt had a positive correlation (0.525). It was concluded that rock mining in Ishiagu has a significant impact on the trace metal levels ofsoils and crops around the area. This is a matter of great concern in view ofthe environmental and health implications.