Sectoral divergences in industrial effluent quality and risk in Bangladesh: Insights from tobacco and non-tobacco industries

This study presents the first comparative assessment of tobacco and non-tobacco industrial effluents in Bangladesh, emphasizing irrigation potential and ecological risks (ER) through multi-index evaluations. Eighteen tobacco effluents were analyzed for twenty-eight physicochemical, ionic, and heavy metal (HM) parameters, while secondary raw data from published articles were analyzed for major non-tobacco Bangladeshi industries. Results revealed clear sectoral divergences. Tannery effluents were the most hazardous, exceeding limits for nearly all parameters, whereas tobacco showed moderate pollution. Across industries, turbidity, total suspended solids, biochemical/chemical oxygen demand, K+, NO3-N, and PO4-P were key drivers of effluent degradation. Sodium hazards were confined to the tannery and sugar. HM analysis identified tannery as the dominant Cr polluter and tobacco with elevated Cd. FTIR Spectroscopy of tobacco effluents revealed diverse organic and metal-linked compounds. The Water Quality Index rated all effluents very poor. The Water Health Index classified tannery and textile-dyeing as extremely poor, while tobacco and most others were comparatively better. HM Pollution and ER Indices illustrated tannery, textile-dyeing, and pharmaceutical as high-risk due to Cr, Cd, Pb, and Mn. These findings highlight both risks and opportunities for nutrient-rich effluent reuse, offering a pollution ranking framework to guide targeted treatment, sustainable irrigation, and ecosystem protection.