Prevalence of bio-aerosols in the outdoor air environment in Uyo Urban, Akwa Ibom state, Nigeria

Abstract

Outdoor bio-aerosols quality in Uyo urban was evaluated for their prevalence using settle plate (culturebased) method. Five (5) locations were established for wet and dry season sampling which included Urban Center, Housing Estate, Local Residence, Open Market and Secretariat complex. Mean viable plate counts of heterotrophic bacteria ranged between 1.386 × 103 (wet season) and 2.018 × 103 (dry season) in Urban Center; 4.82 × 102 (wet season) and 9.64 × 102 (dry season) in Housing Estate; 4.22 × 102 (wet) and 1.476 × 103 (dry) in Local Residence; 1.386 × 103 (wet) and 2.470 × 103 (dry) in Open Market, and 7.23 × 102 (wet) and 1.024 × 103 (dry) in Secretariat Complex while the mean viable plate counts of heterotrophic fungi ranged between 9.94 × 102 (wet) and 1.777 × 103 (dry) in Urban Center; 1.054 × 103 (wet) and 1.265 × 103 (dry) in Housing Estate; 7.23 × 102 (wet) and 1.536 × 103 (dry) in Local Residence; 1.325 × 103 (wet) and 2.048 × 103 in Open Market, and 6.93 × 102 (wet) and 1.084 × 103 in Secretariat Complex. Bacteria isolated were Micrococcus nishinomiyaensi, Staphylococcus aureus, Escherischia coli, Bacillus subtilis, Serratia marcescens, Staphylococcus saprophyticus, Shigella dysenteriae, Proteus vulgaris, Salmonella indica, Pediococcus acidilactici, Staphylococcus albus, Pseudomonas aeruginosa, Micrococcus roseus. The fungi isolated included Aspergillus glaucus, Geotricum sp., Verticillium sp., Pichia sp., Candida tropicalis, Phoma sorghina, Fusarium sp., Aspergillus niger, Absidia sp., Cladosporium carrionil, Candida albicans, Rhizopus oligosporus, Alterneria alternate, Botrytis cinerea, Aspergillus flavus, Epicoccum nigrum, Diplodia seriata, Aspergillus fumigates, Eurotium sp., Penicillium expansum, Sacchromyces cerevisiae, Monilia sp., Humicola sp., Cephalosporium sp., Aspergillus clavatus, Scopulariopsis sp., Penicillium italicum, Penicillium nalgiovense, Trichoderma viride and Moniliella acetoabutens. Bacillus subtilis showed 80% prevalence in both wet and dry seasons. The only fungal isolate that showed 100% prevalence during wet season was Aspergillus glaucus. Escherichia coli were encountered in the open market and urban center stations revealing the unsanitary status of the environment. Many of the microorganisms isolated have been implicated in various human ailments and their effects may be curtailed by adopting improved wastes management approaches in Uyo City Bio-aerosol concentration was found to be high in dry season than wet season. This is because of increase in suspended particulate matter in atmospheric air. The present study has provided evidence of microbial load in outdoor ambient air at different locations.