ABSTRACT
The physiochemical and bacteriological qualities of abattoir effluents and the receiving Ikpoba River (Benin City, Nigeria) were evaluated to ascertain the impact of abattoir effluent on the River. Water samples were collected for six weeks from point source of abattoir effluent (PS), canal into which effluents are discharged (CP), 500 m upstream (US) and 500 m downstream (DS) from points where CP makes contact with the Ikpoba River, Benin City, Nigeria. The physicochemical (pH, temperature, BOD, turbidity, nitrate, suplhate, phosphate, total suspended solids (TSS), and total dissolved solids,) and bacteriological (total heterotrophic bacterial counts, total coliform, E. coli, and Pseudomonas species) qualities of test samples were determined using standard methods. The antibiogram of selected Pseudomonas strains was determined and interpreted using the description of Clinical Laboratory Standard Institute (CLSI). pH ranged from 5.61 to 7.03, while temperature varied between 22.2°C and 30°C. The highest value for BOD was 35.37 ± 0.27 mg/l, whereas the lowest was 1.03 ± 0.01 mg/l. Other physicochemical parameters recorded the following ranges: turbidity, 0.035 NTU to 5262.7 NTU; nitrate,0.026 ± 0.002 mg/ml to 21.74± 0.042 mg/ml; sulphate, 0.047 ± 0.001 mg/ml to 57.59 ± 0.67 mg/ml; phosphate,0.015 ± 0.001 mg/l to 3.23 ± 0.002 mg/l; TSS, 250.00 ± 0.1 mg/l 10500.00 ± 0.15 mg/l; and TDS, 10.00 ± 1.00mg/l to10300.00 ± 0.1 mg/l. Total heterotrophic bacterial counts varied from 1.1 × 103 ±0.28cfu/mL to 1.95×106±0.48 cfu/mL; while mean Escherichia coli count ranged between 0.0 and 4.9×105±0.49 cfu/mL; whereas total coliform counts varied from 0.0 to1.2×106±0.28 cfu/mL; and Pseudomonas counts ranged between 0.0 and 1.4×103cfu/ml. The antibiotic susceptibility pattern of selected Pseudomonas strains showed resistance to oxacillin (100%), vancomycin (52.6%), tetracycillin (50%), gentamycin (26.67%) and ceftriaxone (20%). However, the strains were sensitive to ceftazidime (81.63%), ofloxacin (80%) and amikacin (74%). The study demonstrated that the abattoir effluents were a considerable contributor of pollutants (including multidrug resistant Pseudomonas spp.) to the Ikpoba River, Benin City, Nigeria.
