Endocrine disrupting compounds reduction and water quality improvement in reclaimed municipal wastewater: A field-scale study along Jialu River in North China

• COD and NH3-N could be effectively removed through the ecological purification.
• The natural EDCs could be effectively eliminated in 18.5 km-scale restored river.
• The synthetic EDCs were difficult to remove through purification of restored river.
• The bioassays in vitro showed that purified water had no direct estrogenic activity.
• The purified water still had the estrogenic activity to fish after 21-day exposure.

Several ecological restoration projects have been constructed along urban rivers in North China to purify reclaimed municipal wastewater and improve the water quality of urban rivers. These projects attempt to address several environmental issues, including treating water contamination that is not fully remediated through standard wastewater treatment. This study investigated the efficiency of reducing endocrine disrupting compounds (EDCs) and estrogenic activity in reclaimed municipal wastewater along an 18.5 km field-scale ecological restoration project in Jialu River. The river only receives reclaimed municipal wastewater without natural effluent in North China. Data show that the chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) of reclaimed municipal effluent improved when compared to the Chinese surface water standard, and natural estrogens, such as estrone (E1) and estradiol (E2), were effectively removed during ecological restoration purification processes. The estradiol activity based on measured EDCs concentrations (ΣEEQEDC) was less than 0.01 ng/L after the ecological purification of restoration river; however, synthetic endocrine disrupting compounds in reclaimed municipal wastewater, such as octylphenol (OP), bisphenol A (BPA), and dibutyl phthalate (DBP), were difficult to eliminate. The bioassays of MDA-kb2 cells and recombinant yeast in vitro showed no direct androgen response and estrogen effect in reclaimed municipal effluent after the purification processes. However, a chorionic long-term (21d) exposure in vivo test showed that exposure to the reclaimed municipal effluents, even after river purification, still significantly induced yolk protein vitellogenin (Vtg) in male zebrafish, leading to abnormal expression of testosterone (T) and E2. This indicates continued potent estrogenic activity to aquatic organisms, even after treatment and purification.

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