Toxicity removal of pharmaceuticals, fluoxetine and caffeine, by electron beam irradiation

Abstract

The wide use of pharmaceuticals and water scarcity are associated to increasing levels of pharmaceutical compounds discharged into water and wastewater worldwide, affecting relevant ecological services, including biodegradation. However, water pollution has also encouraged studies applying advanced oxidative processes (AOP) in organic pollutant degradation. Among AOPs, ionizing radiation has been proven an effective technology for organic compound removal from waters and wastewater. The objective of this study was to assess Electron Beam (EB) irradiation in the degradation of caffeine and fluoxetine and their binary mixture in pure aqueous solutions. The degradation of these pharmaceuticals was evaluated by GC/MS analyses. The degradation dose response was higher for the caffeine and fluoxetine mixture (1:1) at 2.5 kGy. This dose led to decreased toxicity towards Daphnia similis for both the fluoxetine + caffeine mixture and the isolated fluoxetine solution, but not for the isolated caffeine. On the other hand, Vibrio fischeri exposure for 15 min indicated toxicity removal for the entire pharmaceuticals sample set and radiation dose. Fluoxetine was the most toxic pharmaceutical, followed by the binary mixture. Thus, we suggest ecopharmacovigilance, where attention should be paid to the increasing amount of pharmaceuticals, caffeine and fluoxetine detected in water.