Physico-Chemical and Microbiological Characterization of Soils Laden with Tannery Effluents in Sokoto, Nigeria

Abstract

Changes in microbial community content as well as physico-chemical properties of soil contaminated with tannery effluents in Sokoto metropolis were determined using standard procedures. The results showed that the soil sample contained a variety of microorganisms which include Bacillus cereus, Bacillus subtilis, Pseudomonas aeroginosa, Proteus mirabilis, Serratia marcensces, Escherichia coli, Streptococcus pyogenes, Klebsiella pneumoniae, Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Penicillium notatum, Mucor pusillus as well as Fusarium sporotrichioides. It also revealed high counts of bacteria and fungi in all the sampling sites. The viable count of bacteria was in the range of 8.60±1.80 – 8.70±0.52 ×105cfu/g while that of fungi was 1.70±0.30 – 2.0±0.10 × 104cfu/g. Similarly, it revealed high levels of sulphide (0.35-0.44mg/g), ammonia (0.40-0.60mg/g), and chromium (0.20-0.26mg/g) in all the sampling sites. These levels exceeded the tolerable levels set by the Federal Ministry of Environment. The presence of these microorganisms and chemical substances pose a potential threat to the local inhabitants of these areas.