Pharmaceutical pollutants in wastewater treatment plants: A global review of occurrence, treatment efficiency, and implications for receiving water bodies

• Pharmaceuticals persist in wastewater due to incomplete removal in WWTPs. • NSAIDs and analgesics have the highest reported concentrations. • Conventional treatments show compound-specific and inconsistent removal efficiencies. • Advanced systems achieve >90 % removal but may create toxic byproducts. • Data gaps highlight need for global monitoring and sustainable management. Pharmaceutical pollutants are increasingly recognized as persistent and emerging contaminants in aquatic environments due to their inadequate removal by wastewater treatment plants (WWTPs). While WWTPs are designed to safeguard environmental health, they have become significant sources of pharmaceutical discharge into the environment. This global review critically evaluates the occurrence, treatment performance, and environmental implications of pharmaceuticals detected in WWTPs receiving domestic, hospital, and industrial effluents. A systematic literature review was conducted using peer-reviewed studies published between 2015 and 2025, following defined inclusion and exclusion criteria. Analgesics, non-steroidal anti-inflammatory drugs, antibiotics, antiretrovirals, hormones, psychiatric drugs, beta-blockers, lipid regulators, and diuretics were among the most frequently reported compounds, occurring in influents and effluents from ng/L to several hundred µg/L. Conventional treatment processes, particularly activated sludge systems, showed highly variable removal efficiencies (<10–90 %), depending on compound properties and operational conditions. Advanced treatment technologies, including ozonation, constructed wetlands, and aerobic granular sludge systems, generally achieved higher removal efficiencies (>90 %) but were constrained by energy demands, operational complexity, and the potential formation of toxic transformation products. Persistent pharmaceutical residues were linked to endocrine disruption, antimicrobial resistance, and chronic toxicity risks to aquatic organisms and human health. This review identifies critical knowledge gaps, particularly the scarcity of data from developing regions, limited comparative assessments across treatment technologies, and insufficient monitoring of transformation products. Future priorities include harmonised global monitoring frameworks, integration of advanced and hybrid treatment systems, and stronger regulatory strategies to mitigate pharmaceutical pollution and protect aquatic ecosystems.