@article {130, title = {Toxicokinetics of Brominated Azo Dyes in the Early Life Stages of Zebrafish () Is Prone to Aromatic Substituent Changes.}, journal = {Environ Sci Technol}, volume = {54}, year = {2020}, month = {2020 04 07}, pages = {4421-4431}, abstract = {

Brominated azo dyes (BADs) have been identified as predominant indoor brominated pollutants in daycare dust; thus, their potential health risk to children is of concern. However, the toxicities of BADs remain elusive. In this study, the toxicokinetics of two predominant BADs, Disperse Blue 373 (DB373) and Disperse Violet 93 (DV93), and their suspect metabolite 2-bromo-4,6-dinitroaniline (BDNA) was investigated in embryos of zebrafish (). The bioconcentration factor of DV93 at 120 hpf is 6.2-fold lower than that of DB373. The nontarget analysis revealed distinct metabolism routes between DB373 and DV93 by reducing nitro groups to nitroso (DB373) or amine (DV93), despite their similar structures. NAD(P)H quinone oxidoreductase 1 (NQO1) and pyruvate dehydrogenase were predicted as the enzymes responsible for the reduction of DB373 and DV93 by correlating time courses of the metabolites and enzyme development. Further in vitro recombinant enzyme and in vivo inhibition results validated NQO1 as the enzyme specifically reducing DB373, but not DV93. Global proteome profiling revealed that the expression levels of proteins from the "apoptosis-induced DNA fragmentation" pathway were significantly upregulated by all three BADs, supporting the bioactivation of BADs to mutagenic aromatic amines. This study discovered the bioactivation of BADs via distinct eukaryotic enzymes, implying their potential health risks.

}, keywords = {Animals, Azo Compounds, Child, Dust, Embryo, Nonmammalian, Humans, Mutagens, Toxicokinetics, Zebrafish}, issn = {1520-5851}, doi = {10.1021/acs.est.9b07178}, author = {Han, Jiajun and Yang, Diwen and Hall, David Ross and Liu, Jiabao and Sun, Jianxian and Gu, Wen and Tang, Song and Alharbi, Hattan A and Jones, Paul D and Krause, Henry M and Peng, Hui} } @article {129, title = {Abundances and concentrations of brominated azo dyes detected in indoor dust.}, journal = {Environ Pollut}, volume = {252}, year = {2019}, month = {2019 Sep}, pages = {784-793}, abstract = {

Dust samples were collected from four indoor environments, including childcare facilities, houses, hair salons, and a research facility from the USA and were analyzed for brominated compounds using full scan liquid chromatography high-resolution mass spectrometry. A total of 240 brominated compounds were detected in these dust samples, and elemental formulas were predicted for 120 more abundant ions. In addition to commonly detected brominated flame retardants (BFRs), nitrogen-containing brominated azo dyes (BADs) were among the most frequently detected and abundant. Specifically, greater abundances of BADs were detected in indoor dusts from daycares and salons compared to houses and the research facility. Using authentic standards, a quantitative method was established for two BADs (DB373: Disperse Blue 373 and DV93: Disperse Violet 93) and 2-bromo-4,6-dinitroaniline, a commonly used precursor in azo dye production, in indoor dust. Generally, greater concentrations of DB373 (<=3850 ng/g) and DV93 (<=1190 ng/g) were observed in indoor dust from daycares highlighting children as a susceptible population to potential health risk from exposure to BADs. These data are important because, to date, targeted analysis of brominated compounds in indoor environments has focused mainly on BFRs and appears to underestimate the total amount of brominated compounds.

}, keywords = {Air Pollution, Indoor, Aniline Compounds, Azo Compounds, Child, Child Day Care Centers, Chromatography, Liquid, Dust, Flame Retardants, Halogenated Diphenyl Ethers, Humans, Hydrocarbons, Brominated, Nitrogen, Tandem Mass Spectrometry}, issn = {1873-6424}, doi = {10.1016/j.envpol.2019.05.153}, author = {Dhungana, Birendra and Peng, Hui and Kutarna, Steven and Umbuzeiro, Gisela and Shrestha, Sujan and Liu, Jing and Jones, Paul D and Subedi, Bikram and Giesy, John P and Cobb, George P} } @article {92, title = {Hydroxylated 2-Ethylhexyl tetrabromobenzoate isomers in house dust and their agonistic potencies with several nuclear receptors.}, journal = {Environ Pollut}, volume = {227}, year = {2017}, month = {2017 Aug}, pages = {578-586}, abstract = {

In the current study, by combining ultra-high resolution (UHR) MS spectra, MS spectra, and derivatization, three hydroxylated isomers of 2-ethylhexyl tetrabromobenzoate (OH-TBB) were identified in Firemaster 550 and BZ-54 technical products. Also, a new LC-UHRMS method, using atmospheric pressure chemical ionization (APCI), was developed for simultaneous analysis of OH-TBB, TBB, hydroxylated bis(2-ethylhexyl)-tetrabromophthalate (OH-TBPH) and TBPH in 23 samples of dust collected from houses in Saskatoon, SK, Canada. OH-TBBs were detected in 91\% of samples, with a geometric mean concentration of 0.21\ ng/g, which was slightly less than those of OH-TBPH (0.35\ ng/g). TBB was detected in 100\% of samples of dust with a geometric mean concentration of 992\ ng/g. Significant (p\ \<\ 0.001) log-linear relationships between concentrations of OH-TBBs, TBB, or OH-TBPHs and TBPH in dust support the hypothesis of a common source of these compounds. OH-TBBs were found to be strong agonists of peroxisome proliferator-activated receptor gamma (PPARγ) and weaker agonists of the estrogen receptor (ER), but no agonistic potencies was observed with the androgen receptor (AR). Occurrence of OH-TBBs in technical products and house dust, together with their relatively strong PPARγ potencies, indicated their potential risk to health of humans.

}, keywords = {Air Pollution, Indoor, Bromobenzoates, Canada, Dust, Environmental Monitoring, Flame Retardants, Halogenated Diphenyl Ethers, Humans}, issn = {1873-6424}, doi = {10.1016/j.envpol.2017.04.094}, author = {Peng, Hui and Sun, Jianxian and Saunders, David M V and Codling, Garry and Wiseman, Steve and Jones, Paul D and Giesy, John P} } @article {94, title = {Response to Comment on "Mutagenic Azo Dyes, Rather than Flame Retardants, are the Predominant Brominated Compounds in House Dust".}, journal = {Environ Sci Technol}, volume = {51}, year = {2017}, month = {2017 03 21}, pages = {3591-3592}, keywords = {Air Pollution, Indoor, Azo Compounds, Dust, Environmental Exposure, Flame Retardants, Halogenated Diphenyl Ethers, Hydrocarbons, Brominated, Mutagens}, issn = {1520-5851}, doi = {10.1021/acs.est.7b00675}, author = {Peng, Hui and Saunders, David M V and Jones, Paul D and Giesy, John P} } @article {95, title = {Mutagenic Azo Dyes, Rather Than Flame Retardants, Are the Predominant Brominated Compounds in House Dust.}, journal = {Environ Sci Technol}, volume = {50}, year = {2016}, month = {2016 12 06}, pages = {12669-12677}, abstract = {

Characterization of toxicological profiles by use of traditional targeted strategies might underestimate the risk of environmental mixtures. Unbiased identification of prioritized compounds provides a promising strategy for meeting regulatory needs. In this study, untargeted screening of brominated compounds in house dust was conducted using a data-independent precursor isolation and characteristic fragment (DIPIC-Frag) approach, which used data-independent acquisition (DIA) and a chemometric strategy to detect peaks and align precursor ions. A total of 1008 brominated compound peaks were identified in 23 house dust samples. Precursor ions and formulas were identified for 738 (73\%) of the brominated compounds. A correlation matrix was used to cluster brominated compounds; three large groups were found for the 140 high-abundance brominated compounds, and only 24 (17\%) of these compounds were previously known flame retardants. The predominant class of unknown brominated compounds was predicted to consist of nitrogen-containing compounds. Following further validation by authentic standards, these compounds (56\%) were determined to be novel brominated azo dyes. The mutagenicity of one major component was investigated, and mutagenicity was observed at environmentally relevant concentrations. Results of this study demonstrated the existence of numerous unknown brominated compounds in house dust, with mutagenic azo dyes unexpectedly being identified as the predominant compounds.

}, keywords = {Azo Compounds, Dust, Flame Retardants, Halogenated Diphenyl Ethers, Hydrocarbons, Brominated, Mutagens}, issn = {1520-5851}, doi = {10.1021/acs.est.6b03954}, author = {Peng, Hui and Saunders, David M V and Sun, Jianxian and Jones, Paul D and Wong, Chris K C and Liu, Hongling and Giesy, John P} } @article {107, title = {Detection, identification, and quantification of hydroxylated bis(2-ethylhexyl)-tetrabromophthalate isomers in house dust.}, journal = {Environ Sci Technol}, volume = {49}, year = {2015}, month = {2015 Mar 03}, pages = {2999-3006}, abstract = {

Ultra-High Resolution LC/mass spectrometry (LC-UHRMS; Thermo Fisher Q-Exactive) was used to identify two novel isomers of hydroxylated bis(2-ethylhexyl)-tetrabromophthalate (OH-TBPH) which were unexpectedly observed in a commercial standard of TBPH. By combining ultra-high resolution (UHR) mass spectra (MS(1)), mass errors to theoretical [TBPH-Br+O](-) were 2.1 and 1.0 ppm for the two isomers, UHR-MS(2) spectra and NMR analysis; the structures of the two compounds were identified as hydroxylated TBPH with a hydroxyl group on the aromatic ring. Relatively great proportions of the two isomers of OH-TBPH were detected in two technical products, Firemaster 550 (FM-550; 0.1\% and 6.2\%, respectively) and Firemaster BZ 54 (BZ-54; 0.1\% and 7.9\%), compared to a commercial standard (0.4\% and 0.9\%). To simultaneously analyze OH-TBPH isomers and TBPH in samples of dust, a method based on LC-UHRMS was developed to quantify the two compounds, using negative and positive ion modes, respectively. The instrumental limit of detection for TBPH was 0.01 μg/L, which was 200-300 times better than traditional methods (2.5 μg/L) based on gas chromatography-mass spectrometry. The analytical method combined with a Florisil cleanup was successfully applied to analyze TBPH and OH-TBPH in 23 indoor dust samples from Saskatoon, Saskatchewan, Canada. Two OH-TBPH isomers, OH-TBPH1 and OH-TBPH2, were detected in 52\% and 91\% of dust samples, respectively. Concentrations of OH-TBPH2 (0.35 {\textpm} 1.0 ng/g) were 10-fold greater than those of OH-TBPH1 (0.04 {\textpm} 0.88 ng/g) in dust, which was similar to profiles in FM-550 and BZ-54. TBPH was also detected in 100\% of dust samples with a mean concentration of 733 {\textpm} 0.87 ng/g. A significant (p \< 0.001) log-linear relationship was observed between TBPH and OH-TBPH isomers, further supporting the hypothesis of a common source of emission. Relatively small proportions of OH-TBPH isomers were detected in dust (0.01\% {\textpm} 0.67 OH-TBPH1 and 0.1\% {\textpm} 0.60 OH-TBPH2), which were significantly less than those in technical products (p \< 0.001). This result indicated different environmental behaviors of OH-TBPH and TBPH. Detection of isomers of OH-TBPH is important, since compounds with phenolic groups have often shown relatively greater toxicities than nonhydroxylated analogues. Further study is warranted to clarify the environmental behaviors and potential toxicities of OH-TBPH isomers.

}, keywords = {Chromatography, Liquid, Dust, Flame Retardants, Limit of Detection, Mass Spectrometry, Phthalic Acids}, issn = {1520-5851}, doi = {10.1021/es505743d}, author = {Peng, Hui and Saunders, David M V and Sun, Jianxian and Codling, Garry and Wiseman, Steve and Jones, Paul D and Giesy, John P} }