Abstract

This study assessed the impact of anthropogenic activities on microbiological and physicochemical quality of surface water at Abonnema Wharf, Port Harcourt, Rivers State, Nigeria. Five stations along the Wharf River (Transportation, Toilet, Refuse Dump, Ship Deck and Control) were assessed. Enumeration of microorganisms revealed substantial microbial contamination of the water body. Total heterotrophic bacterial counts ranged from 1.01±0.75 × 10⁵ CFU/mL to 5.19±3.63 × 10⁵ CFU/ml, while total fungal counts ranged from 1.13±0.85 × 10⁴ to 1.36±1.25× 105 CFU/mL. Hydrocarbon-utilizing bacteria ranges from 6.00 ±9.06 × 104 to 2.01±2.26 × 105 and Hydrocarbon-utilizing fungi at 0 to 2.63±3.77 × 105 CFU/m, Total coliform count ranges from 7.50 ±2.88 × 103 to 1.26 ±1.16 × 10⁵ and faecal coliform counts ranges from 4.25±3.30 × 10⁴ to 1.18±2.18× 10⁵ CFU/mL at the Transportation station, showing widespread faecal pollution, Salmonella/Shigella ranges from 8.50±10.74 × 10⁴ to 2.29±1.89× 10⁵, Vibrio 1.25±2.50 × 10³ to 5.13±6.61× 10⁴. Physicochemical parameters varied significantly between stations and months (P < 0.05). Total dissolved solids rose from 6,480 mg/L in January to 18,590 mg/L in April, and biochemical oxygen demand rose from 0.70–0.90 mg/L to 22.13–25.34 mg/L. Cadmium, copper, zinc and lead ranged from 0.064–0.113, 0.037–0.088, 0.101–0.590 and 0.191–0.326 mg/L respectively, while mercury was below detectable limits. Total petroleum hydrocarbon concentrations exceeded recommended limits at all stations. Bacterial isolates belonging to nine genera were identified, along with fungal isolates of Aspergillus, Rhizopus, Mucor, Candida and Penicillium. Molecular analysis confirmed selected isolates as Escherichia coli strain CEE10, Salmonella enterica subsp. enterica serovar Paratyphi B strains F11 and F12, Pseudomonas fluorescens strain PM5153, Pseudomonas aeruginosa strain BAQVP6 and Aeromonas caviae strain A8. The findings demonstrate severe microbiological contamination, faecal pollution, hydrocarbon contamination and heavy metal accumulation in the surface water, highlighting the urgent need for improved sanitation, pollution control and continuous environmental monitoring.