Assessment of Heavy Metals Contamination in Surface Soil of Ishiagu, Southeastern Nigeria.

Identification and quantification of heavy metals contamination in soil is very important as far as human health and environmental quality protection are concerned. Heavy metals enter the soil through natural and anthropogenic sources but contamination concern is mainly associated with anthropogenic input which is capable of increasing the natural concentration to contamination and toxic levels. Heavy metals can migrate from contaminated soil to other components of the environment with the possibility of human exposure and severe health implication. This study investigated heavy metals contamination of soils in Ishiagu area using pollution indices. Soil samples were collected at various points within the study area at depths of 0-20cm. Collected soil samples were analyzed for total metal concentration using ICP-OES after Aqua regia digestion in Bureau Veritas laboratory, Canada. The result of the analysis showed that heavy metals content in Ishiagu soil varies with location and is in the order: Zn (5 – 1450), Ni(1 – 73 ) Cu (3 – 37 )Cr(6 – 64 )Fe (2800 – 80800 )Al (2200 – 27400 ). The average concentration of the metals in the soil of the study area is in the order: Fe>Al > Zn>Cr > Ni> Cu. Based on the calculated average contamination Factors (CFs), there is moderate contamination of Zn in the investigated soil while the contamination level of other heavy metals that include Cr, Ni, Cu, Al and Fe are low; mean values less than 1(CF<1).The Igeo values calculated for each location range from practically uncontaminated with Cr, Ni, Al, Fe and Cu in all the locations to moderately contaminated with Zn in mining areas. However, the average igeo values for all the metals indicate no contamination in the study area soil. The knowledge of soil contamination status is relevant for environmental management decision.