Heavy Metal Distribution and Contamination in Soils around Enyigba Pb-Zn Mines District, South Eastern Nigeria

Twelve {12} soil samples were collected from the Pb – Zn mining district of Enyigba, Ameri and Ameka in the Abakaliki area of Ebonyi State, south-eastern Nigeria and analysed for As, Cd, Cu, Pb, Zn, Ni, Co, Mn, Ca and pH. The physico-chemical analyses show that pH is fairly acidic to neutral (5.3-7.0) resulting from the dissolution of the sulphide ore waste dump into the soil. The heavy metal mean trend indicates that As > Cd > Co > Mn > Cu > Ni > Pb > Zn. Ca is also high. The variations observed for the heavy metals suggest that both geologic and anthropogenic activities may be responsible for their distribution. Soil contamination is assessed on the basis of enrichment factor (EF) and contamination factor (CF). The results of enrichment factor (EF) show that using Mn concentration in the background value, Cd show extremely high enrichment, Cu, Pb and As have significant enrichment, while Co, Zn and Ni show moderate to low enrichment. The CF values for the soils indicate very high contamination for Cd, high concentration for As while Pb, Cu, Co, Mn, Ni and Zn show moderate contamination. Keywords: Soil Contamination, Partial Leach Test, Enrichment/Contamination Factor, Enyigba, Pb-Zn Mine

Lithostructural description and metalogeny of Alagbede gold deposit, West Central Nigeria

Alagbede gold deposit located about 25km northwest of Malete in Moro Local Government Area of Kwara State, West Central Nigeria consists of gold-bearing quartz veins as stringers set in metasediments (quartzites and talc schist) overlying the migmatite gneiss basement. It is a southern extension of the northwestern end of Yauri goldfield, resulting from the development of the intercontinental Anka-Yauri-Iseyin (AYI) transcurrent fault during the Pan-African. Evidence of granitization abounds within the gneisses of the area. Structural features mapped in the area include folds, faults and joints. Discordant and concordant shear planes are partly healed with vein quartz ranging from 2-8m depth. The ongoing study indicates the preponderance of a reducing environment of sulphide association with fine-grained gold in vein quartz and schitose rocks. The general NNE to SSW trends suggest a temporal and spatial correlation with other Nigeria goldfields. Keywords: Gold, Deposit, Metasediments, Transcurrent, Fault, Sulfide