## 3 Endocrine-Disrupting Compounds EDCs
### Psychotropic Drug Degradation
#### 3.6.2 Fluoxetine  
Fluoxetine (FLX) is another example of a psychotropic drug whose use has steadily increased in recent years. This increased consumption is mainly due to the increasing prevalence of mental disorders in modern societies. This causes an increase in pharmaceutical residues, initially in the wastewater discharged to the treatment plant and, finally, in the environment. Fluoxetine causes endocrine disruption in some aquatic species [86].  
One of the first applications of ionizing radiation to FLX degradation was the degradation in an aqueous solution with an initial concentration of 19.4 \(\pm\) 0.2 mg dm\({}^{-3}\) by electron beam [87]. Degradation of more than 90% was obtained at the dose of 0.5 kGy; however, 80% of the total concentration of organic carbon remained in the solution even after the dose of 7.5 kGy.  
Based on the identified products of fluoxetine decomposition in the first step, the electrophilic addition of OH radicals to aromatic rings is postulated. In the next steps, further hydroxylation of fluoxetine molecules and accompanying defluorination are observed. A 30% efficiency of F\(-\)ion removal was observed for doses above 1 kGy. Based on the determination of the concentration of the formed NO\({}_{3}\)\({}^{-}\) and NH\({}_{4}\)\({}^{+}\) ions, it can be estimated that, after the application of 7.5 kGy, the nitrogen-bonded carbon atoms are mineralized by 8.5%.  
The decomposition of FLX primarily by a reaction with the \({}^{\bullet}\)OH radical was also confirmed by Jl et al. [88]. In the reaction with the radical \({}^{\bullet}\)OH, FLX formed a hydroxylated adduct of the aromatic ring, while in the reaction of FLX with the anion of the sulfate radical (SO\({}_{4}\)\({}^{\bullet-}\)), a cation of the benzene radical was formed; in reaction with H\({}_{2}\)O, this then provided the adduct \({}^{\bullet}\)OH. The rate constants for the reaction of FLX with hydroxyl radical \({}^{\bullet}\)OH, hydrated electron (\(\mathrm{e_{aq}}^{-}\)), and sulfate radical SO\({}_{4}\)\({}^{\bullet-}\) were also determined and were \(7.8\times 10^{9}\); \(2.3\times 10^{9}\) and \(1.1\times 10^{9}\) M\({}^{-1}\)s\({}^{-1}\), respectively. In addition, it has been shown that an acidic solution is more favorable for FLX degradation and the presence of inorganic anions has little or no effect on the electron beam degradation efficiency of FLX [89]. The proposed mechanism of degradation of FLX in such conditions is presented in Figure 7.  
The application of an electron beam to an aqueous solution of FLX and to a mixture of FLX and propranolol, a popular hypertension drug, caused a significant decrease in  
Figure 7: Proposed degradation pathway of FLX degradation using EB [89].  
toxicity in both cases [90]. The application of a 5 kGy dose allowed for an 80% reduction in toxicity for both single pharmaceuticals and the binary mixture towards _Daphnia similis_, and a 20% reduction towards _Vibrio fischeri_. It is interesting to note that the use of higher doses of 7.5 and 10 kGy enhanced the toxic effects compared to non-irradiated samples. Moreover, Jl et al. [88] observed a significant decrease in toxicity of electron beam-treated FLX solutions towards _Daphnia similis_ by about 87%, and slightly less towards _Vibrio fischeri_, by about 10%.