Pathogenic Microbes from Unprotected Landfills Pose Health Hazards with Potentials of Disease Outbreaks in Nigeria

Aims: This study assessed some health hazards associated with landfills and waste dumping by comparing pathogenic microbes from Olusosun Landfill and a control field in Lagos, Nigeria.

Study Design: A comparative, investigative survey.

Place and Duration of Study: Biotechnology Laboratory, Federal Institute of Industrial Research, Oshodi, Lagos, between August 2015 and February 2016.  

Methodology: Soil samples were collected from the superficial layers (1-20 cm) of alfisol at the landfill and a field located about 1000 meters from the dumpsite. Coliform counts, identification of bacteria and susceptibility to antibiotics were carried out.  One-way Analysis of variance (ANOVA) was used for statistical analysis, with level of significance at 0.05.

Results: Coliform counts were 51×10⁵ and 38 ×10⁵ CFU g^-1 dry soil for landfill soil and field soils respectively. Species of Gram-negative bacteria (16) and Gram-positive bacteria (20) found in landfill soil outnumbered Gram-negative bacteria (7) and Gram-positive bacteria (10) found in field soil. potential pathogenic species isolated from landfill soil were Enterobacter, Escherichia coli, Klebsiella, Pseudomonas aeruginosa, Clostridium, Corynebacterium, Micrococcus, and Staphylococcus, outnumbering pathogenic species in field soil. 56.3% of Gram-negative bacteria and 55.0% of Gram-positive bacteria from landfill soil gave Multiple Antibiotic Resistance (MAR) Index above 0.5. Significant differences (P < 0.05) existed between the MAR Index of Gram-negative bacteria in landfill and field soils, but no significant differences (P = 0.6348) between Gram-positive bacteria in landfill and field soils.

Conclusion: The findings reveal that pathogenic species of bacteria inhabiting landfill soil are more diverse and numerous than in field soil. The presence of coliforms in landfill soil is an indication of faecal contamination. This implies that the presence of landfills, though needful, poses health hazards which cannot be overlooked. The author emphasises the importance of sterilizing waste before dumping, citing landfills far from residential areas, water bodies and farms, as well as provision of potable water.