Efficiency of selected wastewater treatment processes in removing estrogen compounds and reducing estrogenic activity using the T47D-KBLUC reporter gene assay.

The occurrence of endocrine-disrupting compounds (EDCs) consisting of natural and synthetic estrogens, namely estrone (E1), 17β-estradiol (E2), estriol (E3) and 17α-ethinylestradiol (EE2) was quantified in wastewater samples. The aim of this study was to assess the removal efficiency for the selected estrogens (E1, E2, E3 and EE2) and reduction of estrogenic activity in wastewater samples from wastewater treatment plants (WWTPs) using different processes. Solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods were used to quantify the selected estrogens in wastewater samples. Estrogenic activity was assessed using the T47D-KBluc gene reporter assay. Results revealed a decrease in estrogen concentrations observed in the effluents of all the WWTPs, except for E2 at Daspoort where no removal was noted. In general, the highest removal for total estrogens was observed at Phola (84%) combining three processes (AP, BF and wetland). The AS at Daspoort had a highest removal of 75% for E3; while at Zeekoegat the highest removal reached 61% for EE2. The PST at Daspoort had no removal recorded for all the compounds, except for the EE2 (33%). The AP and BF systems at Phola contributed to a higher removal of selected compounds. Downstream of the wetland at Phola no removal was recorded for E3; while the highest removal reached 61% for E1. The best performance in terms of the overall influent-to-effluent removal efficiency was observed at Phola WWTP, where E1 removal of 85% was recorded. The highest estrogenic activity in the effluent was reported at Phola, with an average estradiol equivalent (EEQ) value of 6.3 ± 6.7 ng/L. However, no anti-estrogenic activity was detected in any of the samples. The daily mass load discharged from the effluent of the three WWTPs was higher for E1 recorded at Zeekoegat (8002.3 ± 6416.3 mg/d), followed by Daspoort (3509.8 ± 849.0 mg/d) and finally Phola (176.1 ± 34.9).