Integrated environmental assessment of Artisanal alluvial gold mining in Nigeria

This paper critically reviewed the state of Artisanal gold mining in Nigeria, its adverse effects on environment and associated health hazards. Geochemical assessment of stream sediments, soil and water samples within the... [ view full abstract ]

This paper critically reviewed the state of Artisanal gold mining in Nigeria, its adverse effects on environment and associated health hazards.
Geochemical assessment of stream sediments, soil and water samples within the vicinity of both abandoned and active artisanal mine sites in Southwestern Nigeria were carried out using Inductively Coupled Plasma Mass Spectrophotometer (ICP-MS) at ACME laboratories, Canada to determine 56 major and trace elements.
Result of different contamination indices such as enrichment and contamination factors revealed that soil and sediments show extremely high enrichment with Zn, Mn, Fe, Th, La, Cr, Ti, Sc, Ce, Pr, Nd, Sm, Gd, Ta, Nb and In, significant enrichment with Pb, Co, W, Eu and Dy and low enrichment with Mo, Cu, Ag, Co, V, P, La, Ba, Al, Sn, Y.
The ecological risk index show that soil and sediments fall within low risk index with Zn, Ni and Cr, moderate risk index with Cu, considerable risk index with Pb and very high risk index with Cd. Potential ecological risk factor (RI) ranged between low to considerable risk of toxic metals to the environment.
The total chronic hazard quotient index of oral exposure to soil contamination in the study area (THI) ranged between 1.58 and 22.69 for children and 0.28 and 4.05 for adult which indicate moderate to high hazard exposure.
Twenty five percent of the water samples show pollution index (PI) above 1 with highest contribution (37.8%) from Pb. Mn, Al, Ni, Fe and As contributed 29.3%, 19.13%, 8.66%, 4.25% and 0.82% respectively.