Physico-chemical Effects of Active Mining of Rare-metal (Sn, Nb and Ta) and Bacteriological Assessment in Lafia Mining Site, Southwestern Nigeria

Environmental assessment is a key to prevent the occurrence of a potential disaster which can arise due to various reasons in the mining field especially active mining of rare metals. This present paper monitors the physico-chemical effect of active mining of rare-metal (Sn, Nb and Ta) and bacteriological assessment of surface water in the active rare-metal mining site. The negative environmental impact exceeded the positive which includes; landscape destruction, ecological destruction, pollution and accidental hazards while the positive impacts are; an increased human population which promoted the agricultural practice and increased settlements.

Twenty-one (21) water samples and twenty-three (23) eluvial soil samples were collected from the stream within the area and analyzed using the Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) method. The pH, EC and TDS of the surface water were measured with an appropriate instrument. The surface water is slightly alkaline and moderately soft while the EC and TDS were below the recommended range. All the trace elements analyzed for the surface water were all below MPL. The bacteriological analysis revealed the presence of the disease-causing bacteria makes the water unsafe for domestic use (even though the water is free from the presence of heavy metals) and can trigger gastrointestinal illnesses, diarrhoea and vomiting. The metal assessment in the soil samples was calculated using Contamination index and Geo-accumulation index revealed that Arsenic (As) and Cadmium (Cd) are anthropogenically inputted into the environment and have moderately polluted the environment.

There is a need for implementation and enforcement of an environmental law which may just be a means of pollution control within mining districts.