Assessment of Heavy Metal Concentration in Soil Impacted Mining-Overburden in Enyigba, Abakaliki, Ebonyi State, Nigeria

This study assessed the concentration of selected heavy metals (Lead and Zinc) from surrounding soil of Royal Salt mining company, Enyigba in Abakaliki LGA, Ebonyi State. Soil samples were collected from nine (9) different locations at depths of 0-15 and 15-30cm. Two (2) samples were collected from each of the nine locations, making it total of eighteen (18) samples. Soil analysis carried out were particle size distribution, pH, available Phosphorus, total Nitrogen, Organic Carbon, organic matter, Calcium, Magnesium, Potassium, Sodium, exchangeable acidity, Aluminium, effective cation exchange capacity, base saturation and two selected heavy metals, Lead (Pb) and Zinc (Zn). Results shows that heavy metals were highest in soil around the disposal site of mine waste. The highest value of Pb and Zn was recorded on tailing down (TD) 14.82 and 25.33mg/kg at 0-15cm depth, 7.22 and 18.93mg/kg at 15-30cm depth respectively. The accumulation of Pb and Zn at the mining site (TD) may be due to mining activities, civil, industrial/anthropogenic activities going on around the site. This study recommends regular monitoring of heavy metal concentration in soil within the mining site and their disposal site in order to conform to international standards set by the WHO.