title: Occurrence of thyroid hormone activities in drinking water from eastern China: contributions of phthalate esters.
abstract: Thyroid hormone is essential for the development of humans. However, some synthetic chemicals with thyroid disrupting potentials are detectable in drinking water. This study investigated the presence of thyroid active chemicals and their toxicity potential in drinking water from five cities in eastern China by use of an in vitro CV-1 cell-based reporter gene assay. Waters were examined from several phases of drinking water processing, including source water, finished water from waterworks, tap water, and boiled tap water. To identify the responsible compounds, concentrations and toxic equivalents of a list of phthalate esters were quantitatively determined. None of the extracts exhibited thyroid receptor (TR) agonist activity. Most of the water samples exhibited TR antagonistic activities. None of the boiled water displayed the TR antagonistic activity. Dibutyl phthalate accounted for 84.0-98.1% of the antagonist equivalents in water sources, while diisobutyl phthalate, di-n-octyl phthalate and di-2-ethylhexyl phthalate also contributed. Approximately 90% of phthalate esters and TR antagonistic activities were removable by waterworks treatment processes, including filtration, coagulation, aerobic biodegradation, chlorination, and ozonation. Boiling water effectively removed phthalate esters from tap water. Thus, this process was recommended to local residents to reduce certain potential thyroid related risks through drinking water.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
authors.forename: Xinxin
authors.initials: X
authors.lastname: Hu
authors.forename: Fengxian
authors.initials: F
authors.lastname: Zhang
authors.forename: Guanjiu
authors.initials: G
authors.lastname: Hu
authors.forename: Yingqun
authors.initials: Y
authors.lastname: Hao
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Zhang
authors.forename: Hongling
authors.initials: H
authors.lastname: Liu
authors.forename: Si
authors.initials: S
authors.lastname: Wei
authors.forename: Xinru
authors.initials: X
authors.lastname: Wang
authors.forename: John P
authors.initials: JP
authors.lastname: Giesy
authors.forename: Hongxia
authors.initials: H
authors.lastname: Yu
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002460:Cell Line; D002681:China; D002522:Chlorocebus aethiops; D003993:Dibutyl Phthalate / Q000032:analysis* / Q000633:toxicity; D060766:Drinking Water / Q000737:chemistry*; D052244:Endocrine Disruptors / Q000032:analysis* / Q000633:toxicity; D004952:Esters; D006801:Humans; D066298:In Vitro Techniques; D011988:Receptors, Thyroid Hormone / Q000819:agonists / Q000037:antagonists & inhibitors*; D013778:Tetrazolium Salts; D013844:Thiazoles; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity; D018508:Water Purification / Q000379:methods
chemical_list: D060766:Drinking Water; D052244:Endocrine Disruptors; D004952:Esters; D011988:Receptors, Thyroid Hormone; D013778:Tetrazolium Salts; D013844:Thiazoles; D014874:Water Pollutants, Chemical; D003993:Dibutyl Phthalate; C022616:thiazolyl blue