Incidence of Alarming Microbial Pathogens over Refuse Dump Sites and Its ‘Harmful Distance’ in Port Harcourt, Southern Nigeria

Aim: Microbial air quality over illegal refuse dump sites in Port Harcourt, Nigeria, was conducted to assess the aero-microbial contaminant of dumpsite to the closest neighbourhood and the harmful distance.

Place and Duration of Study: The dump sites were located at oil mill market (Latitude 4.8578 N4°51'28.06344'' Longitude 7.06653 E7°3'59.50152'') and Iloabuchi Timber market (longitude N4.790191, latitude E6.988416) all in Port Harcourt, South South Nigeria. The samplings were carried out between June (dry season) and July (wet season) 2018.

Methodology: The microbial concentration of air around the dump sites were measured using the “sedimentation method” that involved exposing different sterile Petri dishes containing nutrient agar, Mac Conkey agar, and sabauroud dextrose agar to the air for ten minutes. The exposures were carried out at different locations within and around the dump site viz; Top of the dumpsite at different altitude (3ft, 6ft and 9ft above dump surface), 0m, 10m away from the dumpsite, and at the nearest neighbourhood which is about 100m away from the dumpsite. These samplings were carried out to the left and right sides of the dump sites. The samplings were carried out between June and July 2018, so as to compare the microbial load between the dry and wet seasons.

Result: The microbes at the dump sites were in most cases higher than the microbes at the neighbourhood (100m away to the left and right). Seasonal occurrence revealed that microbial load in air during the dry season (6.037±0.92 cfu/min-m2) is higher than during the wet season (1.814±0.19 CFU/min-m2). Percentage variation amongst heterotrophic bacterial isolates revealed, Staphylococcus massiliensis (47.90%) > Erwinia psidii (18.24%) > Shigella dysenteriae (18.17%) > Bacillus simplex (6.08%) > Saminicoccus kunminingensis (3.23%) > Corynebacteriun afermentans (3.00%) > Paenibacillus celluositrophycus (2.25%) > Streptococcus parasuis (5.26%); percentage variation amongst enteric bacterial isolates revealed, Staphylococcus aureus (28.57%) > Geobacillus stearothermophilus (20.82%) > Escherichia coli (8.16%) and Bacillus carboniphilus (8.16) > Salmonella enterica (6.94%) > Bacillus smithii (6.12%) > Macrococcus brunensis (4.49%) > Lactobacillus kitasatonis (3.67%) > Klebsiella pneumonia (2.86%) > Staphylococcus saccharolyticus (2.45%) > Bacillus badius (2.04%) = Paenibacillus lautus (2.04%) > Brevibacillus laterosporus (1.63%). The fungal distribution revealed, Aspergillus fumigatus (16.62%) > Microsporium canis (15.40%) > Aspergillus flavus (14.75%) > Aspergillus niger (10.99%) > Conidiobolus coronatus (10.19%) > Pheaocremonium parasiticum (6.97%) > Fusarium chlamydosporium (6.70%) > Trychophyton etriotrephon (5.63%) > Trychophyton quinckeanum (4.02%) > Lichtheeimia corymbifera (3.57%) > Cladosporium cladosporioides (2.95%) > Saccharomyces spp (2.68]%).

Conclusion: The presence of microbial pathogens such as Escherichia coli, Staphylococcus aureus, Bacillus spp, Klebsiella pneumonia, Salmonella enterica and Aspergillus species, is alarming and of great health concern. The harmful distance exceeds 100m away from the dump site which encroached 30 meters into residential areas. This research work revealed the relevance of Environmental air monitoring in any Governmental Waste Management System and the potential hazard of open dump system of waste disposal around residential area.