title: Distribution of estrogenic steroids in municipal wastewater treatment plants in Tehran, Iran.
abstract: BACKGROUND
  Estrogenic steroids such as estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethinylestradiol (EE2) are among the most potent endocrine disrupting compounds (EDCs). Compared with North America, Europe and Japan there is no reliable information on the concentration of steroid hormones in wastewater treatment plants (WWTPs) influents and effluents in Iran. The aim of the present study was to determine the amounts of E1, E2, E3, and EE2 influents and effluents of 7 municipal WWTPs across Tehran, the capital city of Iran, in two seasons, summer and autumn, through solid-phase extraction (SPE) gas chromatography-mass spectrometry (GC-MS).
  
  
  RESULTS
  The results showed that the concentrations of E1, E2, and EE2 in influents ranged from 6.54-18.76 ng/L, 1.02-8 ng/L and 4.18-11.76 ng/L, respectively. Also, the concentrations of E1, E2, and EE2 in effluents ranged from 1.04-4.99 ng/L, 0.5-2.20 ng/L and 0.5-2.58 ng/L, respectively. The levels of E3 were below the detection limit (0.5 ng/L). The percentage removal rate of E1, E2 and EE2 ranged between 61.76-87.25%, 50.98-82.63%, and 66.3-90.25%, respectively. Results indicated no significant correlation between hormone concentrations and seasons.
  
  
  CONCLUSIONS
  The study showed that WWTP number 7 had significant differences in influent hormone concentrations compared with others. Results only showed a significant relationship between hormones and TSS removal rate, but there was no significant relationship between hormones and COD removal rate. The removal rate of hormone in WWTP number 4 and 7 were significantly different from the others. There was no significant correlation between hormone concentrations and seasons.
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, University of Medical Sciences, Tehran, Iran.
authors.forename: Azita
authors.initials: A
authors.lastname: Mohagheghian
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, University of Medical Sciences, Tehran, Iran ; Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ramin
authors.initials: R
authors.lastname: Nabizadeh
authors.affiliation: Center for Water Quality Research (CWQR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran ; Department of Environmental Health Engineering, School of Public Health, University of Medical Sciences, Tehran, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Mesdghinia
authors.affiliation: Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Noushin
authors.initials: N
authors.lastname: Rastkari
authors.affiliation: Center for Solid Waste Research (CSWR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran ; Department of Environmental Health Engineering, School of Public Health, University of Medical Sciences, Tehran, Iran.
authors.forename: Amir Hossein
authors.initials: AH
authors.lastname: Mahvi
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, University of Medical Sciences, Tehran, Iran.
authors.forename: Mahmood
authors.initials: M
authors.lastname: Alimohammadi
authors.affiliation: Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran ; Department of Environmental Health Engineering, School of Public Health, University of Medical Sciences, Tehran, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Yunesian
authors.affiliation: Department of Human Ecology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Ahmadkhaniha
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, University of Medical Sciences, Tehran, Iran.
authors.forename: Shahrokh
authors.initials: S
authors.lastname: Nazmara
keywords: Endocrine disrupting compounds; Estrogenic steroids; Municipal wastewater treatment plant; Solid-phase extraction