Comparative Study of Physicochemical, Bacteriological and Heavy Metal Quality of Water in Selected Fish Farms in Abuja, Nigeria

Abstract

Nigeria's growing aquaculture sector faces critical water quality challenges that threaten fish health and food safety, yet limited systematic assessment exists for urban fish farming environments. This study comparatively assessed physicochemical, bacteriological, and heavy metal quality of water in three selected fish farms in Abuja, Nigeria. The study was conducted over five weeks (November 2024–January 2025), with water samples collected in triplicates from inlet and outlet points and analyzed using standard APHA methods for physicochemical parameters, culture and molecular techniques for bacterial identification, and Atomic Absorption Spectroscopy for heavy metals. Data were analyzed using ANOVA and Kruskal-Wallis tests. Results revealed that all farms exhibited suboptimal water quality with dissolved oxygen levels critically below standards (0.18 ± 0.07 mg/L vs. recommended >5 mg/L), acidic pH (6.4 ± 0.41), and elevated chemical oxygen demand (98.72 ± 19.90 mg/L). Nine bacterial species were identified from thirty isolates, with Escherichia coli being predominant (60%), followed by Staphylococcus sp. and Shigella sp. (10% each), while Campylobacter , Proteus , Enterococcus , Salmonella , Enterobacter , and Bacillus species were each detected at 3.3%. Heavy metal concentrations varied significantly across farms with manganese concentrations ranging from 0.18 ± 0.12 mg/L in Farm A to 0.24 ± 0.25 mg/L in Farm C. Zinc (Zn) levels were highest in Farm V at 0.28 ± 0.21 mg/L and lowest in Farm A at 0.20 ± 0.11 mg/L. Nickel (Ni) concentrations remained relatively consistent across all farms. The study concludes that critical water quality deficiencies across all examined fish farms pose significant risks to fish health and public safety, necessitating urgent implementation of water quality management interventions and strengthened regulatory oversight for sustainable urban aquaculture development.