Environmental Assessment of Artisanal Gold Mining on Soils of a Community within Southwestern, Nigeria

Abstract

Artisanal gold mining a means of livelihood comes with its public health challenge in most Sub-Saharan African countries. The study therefore evaluates extent of artisanal gold mining pollution on the environment and public health in communities within Ilesha Osun Nigeria. The study was field and laboratory based. Thirty–five (35) top soil samples (0-20cm) were randomly collected around Ijana, Itagunmodi, Epe, Igbadae and Ifewara communities. Samples were analyzed using an Agilent 700 series Inductively Coupled Plasma (ICP) for the 35 element suite in Acme Laboratory, Canada. Statistical evaluation was done using geo–accumulation index, enrichment Factor, contamination factor, pollution load index, contamination degree and nemerow pollution Index. The heavy metal pollution level in soils was assessed using potential ecological risk index. Human health risk was assessed using hazard index, carcinogenic risk index and non–carcinogenic risk index. Results of metal content in the soils revealed wide variation in heavy metal concentration. The mean metal content of soil when compared with crustal average was higher with decreasing order Cr > Bi > Sb > Sn > W > As > Mo > Ag > Cd. The results of the contamination indices carried out showed that Bi, Sc and V contributed greatly to very high contamination of the soils. Health risk assessment revealed that the children are more prone to non–carcinogenic diseases than adults in the area. However, carcinogenic health risk showed that adults are prone to this type of health risk through oral ingestion of Cr. This study therefore uncovered that heavy metals extending over large areas may pose great threat to the environmental media.