Microbial Impact Assessment of a Municipal Abattoir Operations on Adjoining Soils of its Receiving Water Milieu

Wastewater from abattoirs have been documented to have harmful impact on the surrounding soil environments. This study therefore, assessed soil samples for possible abattoir wastewater contamination of physicochemical parameters and microbial composition from a mini abattoir in South Local Government Area of Ondo State, Nigeria. Soil samples were collected from the soil 2 m away from abattoir site and 50 m upstream and 50 m downstream. The pH, soil moisture, organic matter, organic carbon, total organic nitrogen, phosphorus and cation exchange capacity were analysed using standard methods. The microbial load of the samples were determined using standard microbiological methods. Abattoir contaminated soils were acidic between 4.8 – 6.4 while the non – abattoir contaminated soil was neutral 7.01. There was significant difference in moisture content, phosphorus, organic carbon, organic matter, total organic nitrogen and cation exchange capacity in abattoir contaminated soil and non – abattoir contaminated soil. In the contaminated soil samples, mean bacterial counts was 15.4 x 104 cfu/ml compared to the 43.01x103 cfu/ml of the uncontaminated soil sample. The mean fungal counts was 39.42 x 102 sfu/ml and 15.2 x 102 sfu/ml respectively. Bacteria such as Bacillus cereus, Enterobacter cloacae, Escherichia coli, Shigella dysenteriae, Citrobacter koseri, Providencia rettgeri, Salmonella typhi, Proteus mirabilis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Lactobacillus plantarum, Actinobacter baumanni and Serratia mascescens, while fungi such as Aspergillus niger, Saccharomyces cerevisiae, Aspergillus flavus, Candida albicans, Penicillium italicum, and Rhizopus stolonifer were isolated from adjoining soils of sampled abattoir. High microbial population and physicochemical parameters of contaminated soil, in this study, further confirmed the need to treat wastewater rather than discharging it directly into the environment.