From prescription to pollution: environmental behavior and breakdown of fluoxetine

Abstract

Fluoxetine (FLX), a widely prescribed antidepressant and one of the most prevalent pharmaceuticals detected in the environment, has piqued significant interest recently due to its persistence and potential ecological effects. Despite its widespread detection, no comprehensive review currently exists that focuses specifically on FLX's environmental behaviour. As a polyfluorinated synthetic organic compound, FLX serves as an ideal model for understanding the broader challenges faced by fluorinated pharmaceuticals. This review presents a critical and integrative assessment of FLX, beginning with its molecular structure and the role of the C–F bond in enhancing the chemical stability and recalcitrance. The review then explores its environmental fate, including its behaviour towards hydrolysis, photolysis, partitioning, susceptibility to microbial attack, potential for bioaccumulation, and interactions and joint toxicity with other co-existing pollutants. This is followed by a comprehensive and critical discussion of existing advanced removal techniques currently investigated for FLX removal. Despite some promising approaches, challenges remain due to the inherent stability of the C–F bond, the toxicity of by-products, and the complexity of the matrix. The review proposes treatment chains, such as adsorption (AC, biochar, nano-adsorbents), followed by chemical (AOPs, electro-Fenton, UVC/solar irradiation) and biological (MBBR, biofilters) as recommendations for future studies. In addition, the review also aims to highlight the need for environmental management of FLX, not only to mitigate its ecological footprint but also to offer broader insights into the class of polyfluorinated pharmaceuticals.