Environmental risk assessment of selective serotonin reuptake inhibitors (SSRIs) after COVID-19 pandemic: a systematic review

Abstract

Nearly 4 % of people worldwide struggle with depression. This mental illness significantly affects daily functioning, and its treatment typically involves long-term pharmacotherapy combined with psychotherapy. Following the COVID-19 pandemic in 2019, the number of individuals suffering from depression increased substantially. One of the most commonly prescribed classes of antidepressants is selective serotonin reuptake inhibitors (SSRIs), such as citalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline. These compounds are detected in the environment, sometimes in considerable concentrations. For instance, fluvoxamine was found in surface waters at levels up to 1.92 μg L⁻¹, while fluoxetine was detected in drinking water at 0.0592 μg L⁻¹. Their environmental presence is largely attributed to the limited efficiency of wastewater treatment plants, which allows these pharmaceuticals to enter aquatic ecosystems. This article presents a comprehensive analysis of recent data (2019–2025) concerning the environmental occurrence and ecological risks of SSRIs. Environmental risk assessments based on Risk Quotient (RQ) calculations, derived from measured environmental concentrations (MEC) and predicted no-effect concentrations (PNEC), using acute and chronic aquatic toxicity data, reveal a concerning picture. Citalopram was the only SSRI assessed to pose a moderate risk to algae (RQ = 0.50). All other SSRIs showed high environmental risks, particularly to algae (RQ range: 1.65–83.00). Fluoxetine was the only substance that exhibited a high risk to algae, crustaceans, and fish. Given the elevated risks, it is crucial to implement preventive measures to limit the environmental concentrations of SSRIs. These should include upgrades to wastewater treatment technologies and the introduction of systematic micropollutant monitoring programs.