17β-estradiol as precursors of Cl/Br-DBPs in the disinfection process of different water samples. (October 2018)

• Record Type: Journal Article
• Authors: Shao, Yanan; Pan, Zihan; Rong, Chuan; Wang, Yinghui; Zhu, Hongxiang; Zhang, Yuanyuan; Yu, Kefu
• Is Part Of: Environmental pollution. Volume 241(2018)
• Page Start: 9
• Page End: 18
• Publication Date: 2018-10
• Subjects: 17β-estradiol -- Sodium hypochlorite -- Marine aquaculture water -- Disinfection -- Br-DBPs; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2018.05.035
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: During chlorine disinfection process, reactions between the disinfectant and 17β-estradiol (E2) lead to the formation of halogenated disinfection byproducts (DBPs) which can be a risk to both ecosystem and human health. The degradation and transformation products of E2 in sodium hypochlorite (NaClO) disinfection processes of different water samples were investigated. The reaction kinetics research showed that the degradation rates of E2 were considerably dependent on the initial pH value and the types of water samples. In fresh water, synthetic marine aquaculture water and seawater, the reaction rate constant was 0.133 min −1, 2.067 min −1 and 2.592 min −1, respectively. The reasons for the above phenomena may be due to the different concentrations of bromide ions (Br − ) in these three water samples which could promote the reaction between NaClO and E2. Furthermore, Br − could also cause the formation of brominated DBPs (Br-DBPs). The main DBPs, reaction centers and conceivable reaction pathways were explored. Seven halogenated DBPs have been observed including three chlorinated DBPs (Cl-DBPs) and four Br-DBPs. The active sites of E2 were found to be the pentabasic cyclic ring and the ortho position of the phenol moiety as well as C9-C10 position. The identified Cl/Br-DBPs were also confirmed in actual marine aquaculture water from a shrimp pond. The comparison of bio-concentration factors (BCF) values based on calculation of EPI-suite showed that the toxicities of the Br-DBPs were stronger than that of their chloride analogues. The absorbable organic halogens (AOX) analysis also suggested that the DBPs produced in the marine aquaculture water were more toxic than that in the fresh water system. Graphical abstract: Highlights: 17β-estradiol was oxidized to Br-DBPs by sodium hypochlorite in marine aquaculture water. Bromide ion accelerate the reaction rate of 17β-estradiol with sodium hypochlorite. Phenolic hydroxyl groups of 17β-estradiol was oxidized when bromide ion was presented. The bio-accumulative properties of Br-DBPs were larger than17β-estradiol.