Transport and transformation pathways of pharmaceuticals, endocrine-disrupting compounds, and PFAS in aquatic systems

ABSTRACT Schematic illustration of transport and transformation pathways of pharmaceuticals, endocrine-disrupting compounds, and PFAS in aquatic systems, showing their release into surface water, movement through wastewater and groundwater compartments, interaction with sediments and biofilms, partial degradation or persistence under natural and engineered processes, and eventual accumulation or transport to downstream ecosystems, highlighting key fate processes including adsorption, dilution, biodegradation, photolysis, and long-range environmental dispersion. Pharmaceuticals, endocrine-disrupting compounds (EDCs), and per- and polyfluoroalkyl substances (PFAS) are widely detected contaminants of emerging concern that pose significant risks to aquatic ecosystems and human health due to their persistence, bioaccumulation potential, and resistance to conventional treatment processes. Originating from anthropogenic sources including municipal wastewater effluents, industrial discharges, and agricultural runoff, these contaminants are increasingly reported in surface water, groundwater, and wastewater systems worldwide. Their physicochemical properties, such as hydrophobicity, molecular structure, ionization state, and environmental stability, govern their mobility, sorption behavior, degradation pathways, and transformation processes. Beyond environmental persistence, these contaminants exert ecotoxicological effects, including endocrine disruption, altered reproductive function, behavioral changes in aquatic organisms, antimicrobial resistance development, and trophic transfer within food webs. Chronic human exposure through drinking water and dietary intake has been associated with endocrine disorders, immunotoxicity, liver dysfunction, reproductive impairment, and elevated cancer risk. This review provides a comparative synthesis of the environmental fate, transport mechanisms, transformation pathways, and bioaccumulation dynamics of pharmaceuticals, EDCs, and PFAS across aquatic matrices. Advances and limitations in analytical detection methods and environmental fate modeling are critically evaluated. The review also discusses regulatory challenges, risk assessment frameworks, and emerging mitigation strategies.