Polycyclic Aromatic Hydrocarbon, Physio-Chemical Properties, and Culturable Microbial Flora of Human Urine-Impacted Topsoils at Commercial Tricycle Parks Along Benin-Sapele Expressway, Benin City, Nigeria

This study presents an evaluation of the microbiological, physiochemical, and poly aromatic hydrocarbon (PAH) properties of human urine-impacted topsoils from a commercial tricycle park located along Benin-Sapele expressway in Benin City. Several analytical procedures (pour plate method, spectrophotometry, atomic absorbance spectrophotometry, and gas chromatography) were utilized in the determination of the heterotrophic microbial flora, physiochemistry, heavy metal and PAH profiles of the topsoils. The heterotrophic bacterial and fungal counts for the urine-contaminated soils ranged from 8.1 × 10^4cfu/g to 18.9× 10^4cfu/g and 4.4 × 10^4cfu/g to 8.0 × 10^4cfu/g, respectively. The heterotrophic bacterial and fungal counts for the control soils were 5.0 × 10^4cfu/g and 3.1 × 10^4cfu/g, respectively. The predominant bacterial and fungal genera were Bacillus sp., Klebsiella sp., Alcaligenes sp., Acinetobacter sp, Enterobacter sp., Micrococcus sp., Staphylococcus sp., Aspergillus sp., Penicillium sp., Trichoderma sp., and Candida sp. All the soils were acidic and sandy. The conductivity and organic carbon values for the urine-contaminated soils ranged from 960 μs/cm to 3240 μs/cm and from 3.58 % to 5.39 %. The potassium values for the contaminated soils ranged from 0.05 meq/100g to 0.12 meq/100g. Iron had the highest heavy metal concentration (788.0 mg/kg). The highest concentration of total hydrocarbon content was 43.6 mg/kg. The PAH values of the contaminated soils ranged from 1.47 mg/kg to 2.12 mg/kg. Considering the bio-magnification potentials of these chemical constituents within the ecological food webs and the disgusting stench and unhygienic nature of the urine-impacted environment, there is a need for increasing public awareness to discourage this low-esteemed human behaviour.