Influence of Abattoir Wastes on Soil Microbial and Physicochemical Properties

Abstract

Influence of abattoir wastes on physicochemical and microbiological properties of soil samples obtained from Akwa Ibom State, Southern Nigeria were investigated using standard analytical and microbiological methods. Studied abattoirs and the control soils were in the sandy-clay-loamy soil category with varying quantities of sand, silt and clay. Bulk density, pH, electrical conductivities, salinity, moisture content, total organic and carbon content, cation exchange capacities, total petroleum hydrocarbon, nitrogen and phosphorus contents of studied abattoir soils were higher than in control.   Essential elements (K, Na, Ca, and Mg) and trace metals (Fe, Zn, Cd, Cu, Pb, Cr and Ni) levels were also higher in abattoir soils than in control though were within the permissible limit in soil except for Fe. Metal pollution index (MPI), enrichment factor (EF), geo-accumulation index (Igeo), degree of contamination (Cdeg) and pollution load index (PLI) of trace metals have also been calculated using existing pollution models. Microbial studies revealed total heterotrophic bacteria ranged from 6.41±0.43 to 7.91±0.58 log10CFU/g while fungal count ranged from 4.94±0.26 to 5.79±0.34 log10CFU/g. Among the four (4) locations, IK2 had the highest heterotrophic bacterial densities of 7.91±0.58 log10CFU/g while IK1 had the highest fungal count of 5.79±0.34 log10 CFU/g. A total of six (6) bacteria (Klebsiella, Micrococcus, Pseudomonas, Bacillus, Escherichiaand Enterobacter) and two (2) fungi (Aspergillus and Penicillium) species were isolated. The study revealed a significant (p=0.05) increase in the number and varieties of microorganisms most of which may be pathogenic but are more often than not indicators of recent faecal pollution in the soil impacted with the abattoir wastes.