Histopathological Effects of Industrial Effluents on Lung Tissues of Wistar Rats

Background: Environmental pollution from industrial effluent discharge poses a significant health risk, particularly through inhalation and ingestion. This study aimed to evaluate the histological effects of treated and untreated effluents from selected chemical and petrochemical industry in Rivers State, Nigeria on the lung tissues of Wistar rats. Methods: A total of 40 adult male Wistar rats were randomly assigned into five groups (n=8 per group). Group 1 served as the control, while Groups 2–5 were administered 100% effluent samples (10 mL/kg body weight) of untreated refinery effluent, treated refinery effluent, treated Notore effluent, and untreated Notore effluent, respectively, via oral gavage for 28 days. Animals were sacrificed on days 3 and 28 to assess acute and chronic effects. Lung tissues were extracted, fixed in 10% buffered formal saline, and processed for histological examination using hematoxylin and eosin (H&E) staining. Results: Histological examination revealed significant inflammatory responses in treated groups. Day 3 samples showed inflammatory cell infiltration, alveolar congestion, and mild epithelial distortions. Day 28 samples demonstrated severe inflammatory cell infiltration, alveolar rupture, congestion, and bronchial epithelial distortion, with more pronounced effects in the untreated effluent groups. Conclusion: Findings indicate that exposure to industrial effluents, particularly untreated samples, induces severe lung tissue damage over time. This study underscores the health risks of industrial effluent pollution and the need for stringent effluent treatment and regulatory enforcement to mitigate environmental and public health hazards.