Speciation Partterns of Some Selected Heavy Metals in the Soil along the Effluent Channels of Juhel Pharmeutical Industry, Awka, Anambra State, Nigeria

摘要

The speciation of some selected heavy metals in soil samples collected along the effluent channels of JUHEL Pharmaceutical industry, Awka was investigated. The pH of the soils had average value of 7.53 and moisture content of 17.96%. The results revealed total metal concentration range of 0.13 mg/kg to 16.49 mg/kg among the metals –Cd, Cr, Pb, Ni, Cu, Co, Zn,Mn, Fe and Ca. Cadmium (Cd) had the lowest metal concentration with a value of 0.13 mg/kg and iron (Fe) had the highest concentration with a value of 16.49 mg/kg. The observed trend for the total metal concentrations was: Fe > Ca > Mn > Pb > Cr > Co > Cu > Ni > Zn > Cd. The computed bioavailability of the metals, for the industry, followed the trend: Ca > Pb > Cu > Cr > Mn > Ni > Cd > Co > Zn > Fe. Metals speciation of the soil samples showed that the highest and lowest partitions were found in the residual and water soluble for the metals Fe, Mn, Pb, Cr, Cu, Ni, Co and Zn, respectively except for Ca which had its highest concentration in the carbonate bound partition, and the lowest concentration in the water soluble fraction. The highest fraction for Cd was found in the residual and Fe-Mn oxide (reducible) forms, with the water soluble fraction having the lowest Cd concentration. Comparison with NESREA standard also revealed low contamination level of the metals, and there was no mean significant difference to conclude that the pollution level of the environment was alarming.