The Assessment of Industrial Wastewater Quality of Selected Pharmaceutical and Food Industries in Kano State Nigeria, West Africa.

Abstract

Industrial wastewater pollution poses a significant threat to environmental sustainability and public health, particularly in developing regions with inadequate regulatory enforcement. This study evaluates the physicochemical and heavy metal characteristics of wastewater discharged from selected pharmaceutical and food industries in Kano State, Nigeria, over multiple seasons (wet and dry) within a two-year period (2023–2024). The objective is to determine contamination levels, compare findings with World Health Organization (WHO) standards, and assess potential ecological and health risks. Key physicochemical parameters analysed include pH, electrical conductivity, total dissolved solids (TDS), temperature, salinity, sulphates, phosphates, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), alkalinity, turbidity, nitrate, and total hardness. Additionally, heavy metal concentrations of zinc (Zn), cadmium (Cd), iron (Fe), copper (Cu), nickel (Ni), arsenic (As), cobalt (Co), lead (Pb), and chromium (Cr) were quantified. Results revealed seasonal variations in wastewater quality, with higher contamination levels observed during the dry season due to reduced dilution effects. Conductivity, salinity, and sulphate concentrations were notably higher in dry seasons, suggesting more concentrated industrial discharges. While most parameters were within WHO limits, conductivity values frequently exceeded the threshold, indicating elevated ion concentration. The presence of heavy metals, particularly Cd, Pb, As, and Cr, exceeded permissible levels in several instances, raising serious health concerns related to bioaccumulation and toxicity. The findings highlight the ecological risks of industrial wastewater discharge, with potential long-term consequences on aquatic ecosystems and human populations reliant on contaminated water sources. Non-compliance with environmental discharge limits underscores the need for enhanced wastewater treatment measures. The study recommends the adoption of advanced treatment technologies such as electrocoagulation, activated carbon filtration, and bioremediation to mitigate industrial pollution. Additionally, stricter regulatory enforcement and regular environmental monitoring are imperative to ensure compliance with discharge standards. This research contributes to the growing body of literature advocating for sustainable industrial waste management, emphasizing a holistic approach integrating industrial responsibility, government oversight, and public health protection.

Keywords: Industrial wastewater, heavy metals, environmental pollution, Kano State, public health, seasonal variation, wastewater treatment, regulatory compliance.