A gas chromatography/mass spectrometry method for the simultaneous analysis of 50 phenols in wastewater using deconvolution technology

Phenolic compounds exist widely in the influents and effluents of sewage treatment plants (STPs) and most are un-regulated. In this study, a gas chromatography-mass spectrometry (GC-MS) method for the simultaneous analysis of 50 phenolic compounds in wastewater was developed. Deconvolution technology was used to identify contaminants that are covered by co-extracted materials. A mass spectral library containing all 50 silylated phenolic compounds was first established and used for deconvolution. Twelve typical phenolic compounds were selected to optimize the sample preparation procedures. Solid-phase extraction using a C18 cartridge coupled with an HLB cartridge was used for pre-concentration and dichloromethane was used for elution. The solutes were derivatized and analyzed by GC-MS. The blank and matrix spike recoveries ranged from 57.46% to 136.4% and 47.87% to 114.8%, respectively. Method detection limits ranged from 3.64 to 97.64 ng L⁻¹. The relative standard deviations of all the recovery experiments were lower than 13.6%. The instrument limits of quantification ranged from 0.7 to 87.7 pg. The method has been applied to analyze the influents and effluents of 5 Chinese STPs. Except for regulated phenolic compounds (phenol and 2,4,6-trichlorophenol), three un-regulated phenolic compounds, including 2-chlorophenol, 2,5-dichlorophenol and 2,4-dichloro-3-ethyl-6-nitrophenol were identified in the effluent wastewater. The detected concentrations of un-regulated phenolic compounds could possibly cause environmental effects, indicating that immediate attention is required to prevent complications.     

In vitro assay for human thyroid hormone receptor β agonist and antagonist effects of individual polychlorinated naphthalenes and Halowax mixtures

Polychlorinated naphthalenes (PCNs) are dioxin-like environmental contaminants. There is growing concern over the endocrine-disrupting effects of PCNs, but very few studies have investigated the effect of PCNs on the thyroid system. This study used a yeast two-hybrid assay, which included the recombinant human thyroid receptor(TR)-β and reporter genes, to characterize the TRβ-disrupting effects of five individual PCN congeners, five PCN Halowax mixtures, and naphthalene. Their agonist and antagonist effects...     

Retinoid X receptor activities of source waters in China and their removal efficiencies during drinking water treatment processes

There is increasing evidence of estrogenic activities of source waters and drinking waters in China based on estrogen receptors(ERs) testing.However,relating such activities to retinoid X receptors(RXRs) in both drinking and source waters are lacking.To rectify this situation,we assessed 23 source water samples from six major river systems in China.We also collected samples at various stages of water processing from three drinking water treatment plants(DWTPs) using a two-hybrid RXR yeast assay with and without metabolism.No RXR agonistic activity was observed,but significant antagonistic activity was detected in all sample extracts.The RXR antagonistic activities of source water sample extracts ranged from 15.2% to 57.8% without metabolism and 11.5% to 68.3% with metabolism,respectively.In the drinking water treatment processes,RXR antagonistic activities without metabolism and with metabolism of up to 31.4% and 37.5% were removed,respectively.Nevertheless,the remaining RXR antagonists in treated drinking water from these source waters could still be harmful to human health.To the best of our knowledge,the occurrence of in vitro RXR disruption activities in source and drinking water has not been previously reported in China.Therefore,an attempt was made to conduct detailed studies investigating RXR disrupting activities and their possible risks in source and drinking water.