Microbiological and chemical evaluation of acid mine drainage from mining sites in Southwestern, Nigeria

Microbial content of acid mine drainage effluents contaminated streams from some geographical areas was evaluated. Water was obtained from acid mine drainage sites in Ekiti and Osun state where twelve (12) samples were obtained from different locations. Culture plating method was used to analyze the samples for bacteria, and Atomic Absorption Spectrophotometer (AAS) was used to determine heavy metals such as Cd, Co, Pb, Cr, Zn, Cu and Mn. The results of biochemical and morphological characterization of the isolates revealed three probable bacterial from the samples which are Bacillus subtilis, Pseudomonas spp. and Staphylococcus aureus; B. subtilis being the bacteria with the highest percentage frequency of occurrence. Heavy metals analysis of the mine drains shows that the concentration of Cd, Co, Pb, Cr and Zn exceeded permissible limit set by WHO except Cu and Mn. The results of this study established the presence of bacterial and heavy metals in acid mine drainage sites, which is an indication that the acid mine effluents are contaminated. It is therefore essential for proper dissemination of information concerning the dangers these microbes and heavy metals could pose to human.