Efficacy assessment of peracetic acid in the removal of synthetic 17α-ethinyl estradiol contraceptive hormone in wastewater

Increasing concerns have been raised on endocrine disrupting chemicals like the sex hormone 17α-ethinylestradiol (EE2), the more since traditional wastewater (WW) treatments appear to be ineffective for their removal. The efficacy of the relatively novel disinfectant peracetic acid (PAA) in EE2 removal was evaluated, as well as its potential effects on WW quality parameters. The treatments tested for EE2 removal were also evaluated in terms of toxicity, through the determination of biochemical responses (antioxidant enzymes, lipid peroxidation and vitellogenin induction) using zebrafish (Danio rerio) as a biological model. PAA contact times less than 20 min appeared insufficient regardless of the PAA dose tested, but a 100% EE2 removal was attained at a PAA concentration of 15 mg/L with a contact time of 20 min. Total suspended solids, chemical oxygen demand and pH in PAA treatments remained well within levels set in European legislation for WW discharge. EE2 induced significant increased vitellogenin (VTG) levels in both female and male fish, indicating increased estrogenic activity, especially in males suggesting an endocrine disruption effect. With the addition of PAA (15 mg/L), however, VTG levels in both sexes returned to control values. Although this PAA treatment showed increased levels of the antioxidant enzyme catalase, the lipid peroxidation levels were similar or even lower than in controls. Overall the results suggest that the use of PAA appears a promising way forward as a less toxic alternative to chlorine disinfection with high efficiency in the removal of EDC like EE2.