Impact of Municipal Solid Waste Dumpsites on Soil Microbial Diversity in Enugu Metropolis, South East Nigeria

The proliferation of open dumpsites in Nigerian urban centres poses significant risks to soil health and microbial ecosystem services. This study investigated the impact of municipal solid waste disposal on soil microbial diversity in and around three major dumpsites in Enugu metropolis. Soil samples were collected at dumpsite cores and at distances of 50, 100, and 200 metres from the dumpsite perimeters, along with control samples from undisturbed agricultural land. Microbiological analyses included total viable count, fungal count, and identification of bacterial genera using standard culture-based and biochemical methods. Physicochemical properties including pH, electrical conductivity, and heavy metal concentrations were also determined to contextualise microbial responses. Results showed significantly reduced bacterial diversity at dumpsite cores compared to control sites, while certain metal-tolerant and hydrocarbon-degrading bacteria were enriched in contaminated soils. Fungal populations showed a different pattern, with increased fungal diversity in soils with high organic loading at dumpsite peripheries. The study highlights the role of waste composition and leachate penetration in shaping soil microbial communities. Findings have implications for understanding microbial-mediated nutrient cycling in degraded urban soils and for identifying potential bioremediation agents. Recommendations include closing open dumpsites in favour of engineered sanitary landfills and exploring microbial consortia from these sites for pollution remediation. Keywords: soil microbial diversity, municipal solid waste, dumpsites, Enugu, urban ecology.