Bacteriological Assessment of Soils of Municipal Solid Waste Dumps of Choba, Rivers State

The study analysed the bacteria associated with the soils of solid waste dump sites in Choba, Rivers State. The total heterotrophic counts of the bacteria present in the soils of the dump sites, their frequencies of occurrence and their lipolytic, cellulolytic and proteolytic potentials were determined; the bacterial isolates that showed zones of inhibition were also screened for their antibacterial activity against Staphylococcus aureus and Escherichia coli. A total of four soil samples were collected from four different dump sites in Choba. The samples were serial diluted up to 10-4 and 0.1ml spread on nutrient agar plates. The total heterotrophic bacteria counts for samples A, B, C and D were 2.8×106 cfu/g, 2.0 × 107 cfu/g, 4.3 × 106 cfu/g and 1.5 × 107 cfu/g respectively. The bacteria isolated with their frequencies of isolation were: Salmonella typhi (75%), Pseudomonas aeruginosa (50%), Shigella flexneri (25%), Escherichia coli (25%), Arthrobacter (50%), Klebsiella (25%), Acinetobacter (25%), Enterobacter (50%), Micrococcus (25%), Citrobacter (25%), Enterococcus faecalis (50%), Bacillus subtilis (25%), Staphylococcus (50%), and Serratia marcescens (50%). Salmonella typhi had the highest frequency of occurrence, being present in three soil samples. The cellulolytic, proteolytic and lipolytic potentials of the isolates were determined using appropriate media. Only Pseudomonas aeruginosa, Acinetobacter, Bacillus subtilis and Serratia marcescens tested positive to cellulose, protein and lipid hydrolysis. Bacillus subtilis exhibited antimicrobial activity during isolation and was tested against E. coli and S. aureus. The zones of inhibition observed against E. coli and S. aureus were 10mm and 15mm respectively. From the results of the analysis, it can be observed that large numbers of diverse species of bacteria are present in dump sites. The presence of pathogenic bacteria in these dump sites has made it imperative that measures be put in place to curtail the potential health hazards that these pathogens can cause.