Microbiological Evaluation of Soil and Wastewater from Major Abattoir Sites in Umuahia, Abia State

Abstract

Abattoirs with their associated activities produce an enormous amount of wastewater that can alter the microbiota of the immediate environment. This study evaluated the microbial profile of wastewater and soil within two major Abattoirs in Umuahia, Abia state, Nigeria. Wastewater and soil samples within the immediate environment (at different depths) were collected aseptically from different locations (Ubakala and Ndioru). The samples were inoculated into culture media for isolation of microorganisms and identified accordingly using standard techniques. The total heterotrophic bacterial count ranged from 8.7x10⁶ – 1.58×10⁷ cfu/g and 8.1x 0⁶ – 1.33×10⁷ cfu/g for the on-site and off-site soil samples, with the Ubakala samples significantly recording higher counts than Ndioru. The wastewater samples from both locations had counts in the range of 9.6x10⁶ – 1.36 × 10⁷ cfu/mL, while coliform counts ranged between 3.7 × 10⁴ – 5.3 × 10⁴ cfu/mL. Diverse microorganisms were isolated as Bacillus subtilis, Lysinibacillus species, Pseudomonas aeruginosa, CONs, Micrococcus species, and Escherichia. coli, Acetobacter species and Enterobacter species, while the fungal isolates included Mucor sp., Rhizopus sp. and Penicillium sp., Curvularia species, Cladosporium species, Aspergillus fumigatus.  The results as obtained in this study revealed that bacterial and fungal diversity was largely higher in onsite samples compared to offsite samples. This is a clear indication of the direct influence of abattoir effluent on soil microbial communities. The contamination level, especially with pathogenic species as seen from this study, shows that the study sites could be breeding grounds conducive for silent transmission of pathogens.