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Detection of retinoic acid receptor agonistic activity and identification of causative compounds in municipal wastewater treatment plants in Japan
Author(s) -
Sawada Kazuko,
Inoue Daisuke,
Wada Yuichiro,
Sei Kazunari,
Nakanishi Tsuyoshi,
Ike Michihiko
Publication year - 2012
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.741
Subject(s) - wastewater , effluent , bioassay , chemistry , agonistic behaviour , sewage treatment , activated sludge , environmental chemistry , retinoic acid , chromatography , biochemistry , biology , ecology , environmental engineering , environmental science , aggression , psychology , psychiatry , gene
Retinoic acid (RA) receptor (RAR) agonists are potential toxicants that can cause teratogenesis in vertebrates. To determine the occurrence of RAR agonists in municipal wastewater treatment plants (WWTPs), we examined the RARα agonistic activities of influent and effluent samples from several municipal WWTPs in Osaka, Japan, using a yeast two‐hybrid assay. Significant RARα agonistic activity was detected in all the influent samples investigated, suggesting that municipal wastewater consistently contains RAR agonists. Fractionations using high‐performance liquid chromatography, directed by the bioassay, found several bioactive peaks from influent samples. The RAR agonists, all‐ trans RA (atRA), 13‐ cis RA (13cRA), 4‐oxo‐atRA, and 4‐oxo‐13cRA, possibly arising from human urine, were identified by liquid chromatography ion trap time‐of‐flight mass spectrometry. Quantification of the identified compounds in municipal WWTPs confirmed that they were responsible for the majority of RARα agonistic activity in WWTP influents, and also revealed they were readily removed from wastewater by activated sludge treatment. Simultaneous measurement of the RARα agonistic activity revealed that although total activity typically declined concomitant with the reduction of the four identified compounds, it remained high after the decline of RAs and 4‐oxo‐RAs in one WWTP, suggesting the occurrence of unidentified RAR agonists during the activated sludge treatment. Environ. Toxicol. Chem. 2012;31:307–315. © 2011 SETAC