Pharmaceutical Micropollutants in Aquatic Environments:An Integrated Review of Environmental Fate, Ecotoxicological Risks, and Hybrid Treatment Approaches

Pharmaceuticals are continually discharged into aquatic environments, where they can cause ecotoxicity, promote antimicrobial resistance, and generate harmful transformation products. Existing reviews often assess treatment technologies individually and provide limited guidance for selecting integrated treatment trains according to contaminant properties and treatment objectives. This review links pharmaceutical occurrence, environmental fate, and ecotoxicological risk with the performance of conventional biological treatment, adsorption, membrane filtration, advanced oxidation processes (AOPs), constructed wetlands, and hybrid systems. It compares the principal removal mechanisms of biodegradation, adsorption, size exclusion, and oxidative transformation and the operating factors that influence efficiency, energy demand, by-product formation, and scalability. No single technology reliably removes the full diversity of pharmaceutical micropollutants. Hybrid treatment trains that combine complementary mechanisms provide broader removal, greater process resilience, and better suitability for water reuse. A practical decision framework is therefore proposed that relates pharmaceutical physicochemical properties, wastewater-matrix characteristics, treatment goals, and process limitations to suitable treatment sequences. This review converts evidence on pharmaceutical fate, ecotoxicity, antimicrobial resistance, and treatment performance into a compound-property-based framework for selecting complementary wastewater treatment trains. It identifies when biological, adsorptive, membrane, oxidative, or nature-based barriers should be combined and specifies residual-risk checks needed for safe discharge and water reuse. Priority research needs include full-scale validation, standardized performance metrics, transformation-product and long-term toxicity assessment, and techno-economic and life-cycle evaluation.