Microbial Quality and Ecotoxicological Effects of Treated and Untreated Industrial Effluents from Food-Processing Industries in Port Harcourt, Nigeria

Ndu Chidiebere Kingsley1, Uzoefuna Chima Casmir2, Ebuoh Maryann Chiamaka3, Mba Cornelius, Elochukwu4 and Nwafor Chinenye Precious5,

1Department of Biochemistry, Faculty of Allied Health Sciences, Cosmopolitan University, Abuja, Nigeria.

2,5Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, State University of Medical and Applied Sciences, Igbo-Eno, Enugu State, Nigeria.

3Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine, State University of Medical and Applied Sciences, Igbo-Eno, Enugu State, Nigeria.

4Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, Enugu State University of Science and Technology, Enugu State, Nigeria.

Corresponding author: Uzoefuna Chima Casmir, casmir.uzoefuna@sumas.edu.ng; +2348061625847

                                                                      Abstract
Water supports life, but it also becomes a direct route for microbial exposure when industrial wastewater is poorly treated before discharge. This study assessed faecal and total coliform contamination in treated and untreated effluents from Dufil Prima Foods Plc and Mac Cannon Nigeria Limited in Port Harcourt, Nigeria, and examined early biochemical responses in juvenile Clarias gariepinus used as aquatic bioindicators. Sixty juvenile fish were obtained from the African Regional Aquaculture Research Centre, University of Port Harcourt, acclimatised for 72 h and distributed into six exposure groups. Fish were maintained for 14 days in normal water, untreated effluents or treated effluents from the two facilities. Coliform counts were determined by standard culture methods, while serum potassium, bicarbonate, aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase were measured as indicators of ionic disturbance and tissue stress. Data were analysed using IBM SPSS Statistics, with significance accepted at p < 0.05. Faecal coliforms were not detected in normal water. Counts were higher in untreated effluents, although the values reported in this study remained below the effluent benchmark adopted by the authors. Total coliform contamination was more persistent. Untreated effluents from both industries contained 37.00 cfu/100 mL, and treated effluent from Mac Cannon still showed detectable contamination. The biochemical data told a sharper story. Fish exposed to untreated effluents, especially from Mac Cannon, showed marked increases in serum potassium, AST and ALT by week 2, which is consistent with osmoregulatory strain and hepatocellular injury. Treated effluents reduced some responses, but they did not remove all biological effects. In my view, the main finding is not simply that treatment helps; it is that the treatment systems, as sampled here, were only partly effective. Stronger effluent polishing, routine microbial verification and biomarker-based monitoring are therefore needed before discharge into receiving aquatic environments.

Keywords: industrial effluent; Clarias gariepinus; coliforms; ecotoxicology; biomarkers; Port Harcourt; wastewater treatment.

CITE AS: Ndu Chidiebere Kingsley, Uzoefuna Chima Casmir, Ebuoh Maryann Chiamaka, Mba Cornelius Elochukwu and Nwafor Chinenye Precious (2026). Microbial Quality and Ecotoxicological Effects of Treated and Untreated Industrial Effluents from Food-Processing Industries in Port Harcourt, Nigeria. INOSR APPLIED SCIENCES 14(3):50-54.
https://doi.org/10.59298/INOSRAS/2026/14.3.5054000