Analysis and occurrence of typical endocrine-disrupting chemicals in three sewage treatment plants

Seven typical endocrine-disrupting chemicals (EDCs), including bisphenol A (BPA), 4-tert-octylphenol (OP), estrone (E1), estradiol (E2), 17a-estradiol (17α-E2), estriol (E3) and 17α-ethinylestradiol (EE2) in wastewater, were simultaneously determined with gas chromatography-mass spectrometry (GC-MS). Samples, including influents, effluents and wastewater of different unit processes, were taken seasonally from three different sewage treatment plants. The result showed that BPA and EE2 were the two main types of EDCs in all the samples. The average concentration of BPA were in the range of 268.1-2,588.5 ng l^-1 in influents and 34.0-3,099.6 ng l^-1 in effluents, while EE2 ranging from 133.1 to 403.2 ng l^-1 and from 35.3 to 269.1 ng l^-1, respectively. Seasonal change of EDCs levels in effluents was obvious between wet season and dry season. Besides, BPA and E3 could be effectively removed by the biological treatment processes (oxidation ditch and A²/O) with the unit removal of 64-91% and 63-100% for each compound, while other five EDCs had moderate or low removal rates. The study also proved that physical treatment processes, including screening, primary sedimentation and pure aeration, had no or little effect on EDCs removal.