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Regulations and Advisories. Toxicol Ind Health 2016. [DOI: 10.1177/074823370001600312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Xiao H, Kuckelkorn J, Nüßer LK, Floehr T, Hennig MP, Roß-Nickoll M, Schäffer A, Hollert H. The metabolite 3,4,3',4'-tetrachloroazobenzene (TCAB) exerts a higher ecotoxicity than the parent compounds 3,4-dichloroaniline (3,4-DCA) and propanil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 551-552:304-316. [PMID: 26878642 DOI: 10.1016/j.scitotenv.2016.02.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 02/02/2016] [Accepted: 02/02/2016] [Indexed: 06/05/2023]
Abstract
3,4,3',4'-tetrachloroazobenzene (TCAB) is not commercially manufactured but formed as an unwanted by-product in the manufacturing of 3,4-dichloroaniline (3,4-DCA) or metabolized from the degradation of chloranilide herbicides, like propanil. While a considerable amount of research has been done concerning the toxicological and ecotoxicological effects of propanil and 3,4-DCA, limited information is available on TCAB. Our study examined the toxicity of TCAB in comparison to its parent compounds propanil and 3,4-DCA, using a battery of bioassays including in vitro with aryl hydrocarbon receptor (AhR) mediated activity by the 7-ethoxyresorufin-O-deethylase (EROD) assay and micro-EROD, endocrine-disrupting activity with chemically activated luciferase gene expression (CALUX) as well as in vivo with fish embryo toxicity (FET) assays with Danio rerio. Moreover, the quantitative structure activity response (QSAR) concepts were applied to simulate the binding affinity of TCAB to certain human receptors. It was shown that TCAB has a strong binding affinity to the AhR in EROD and micro-EROD induction assay, with the toxic equivalency factor (TEF) of 8.7×10(-4) and 1.2×10(-5), respectively. TCAB presented to be a weak endocrine disrupting compound with a value of estradiol equivalence factor (EEF) of 6.4×10(-9) and dihydrotestosterone equivalency factor (DEF) of 1.1×10(-10). No acute lethal effects of TCAB were discovered in FET test after 96h of exposure. Major sub-lethal effects detected were heart oedema, yolk malformation, as well as absence of blood flow and tail deformation. QSAR modelling suggested an elevated risk to environment, particularly with respect to binding to the AhR. An adverse effect potentially triggering ERβ, mineralocorticoid, glucocorticoid and progesterone receptor activities might be expected. Altogether, the results obtained suggest that TCAB exerts a higher toxicity than both propanil and 3,4-DCA. This should be considered when assessing the impact of these compounds for the environment and also for regulatory decisions.
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Affiliation(s)
- Hongxia Xiao
- Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
| | - Jochen Kuckelkorn
- Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
| | - Leonie Katharina Nüßer
- Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
| | - Tilman Floehr
- Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
| | - Michael Patrick Hennig
- Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
| | - Martina Roß-Nickoll
- Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; College of Resources and Environmental Science, Chongqing University, Tiansheng Road Beibei 1, Chongqing 400715, People's Republic of China.
| | - Andreas Schäffer
- Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Xianlin Avenue 163, Nanjing 210023, People's Republic of China; College of Resources and Environmental Science, Chongqing University, Tiansheng Road Beibei 1, Chongqing 400715, People's Republic of China.
| | - Henner Hollert
- Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Xianlin Avenue 163, Nanjing 210023, People's Republic of China; College of Resources and Environmental Science, Chongqing University, Tiansheng Road Beibei 1, Chongqing 400715, People's Republic of China; Key Laboratory of Yangtze Water Environment, Ministry of Education, Tongji University, Siping Road 1239, Shanghai 200092, People's Republic of China.
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Wilczyńska-Piliszek AJ, Piliszek S, Falandysz J. Use of quantitative-structure property relationship (QSPR) and artificial neural network (ANN) based approaches for estimating the octanol-water partition coefficients of the 209 chlorinated trans-azobenzene congeners. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2012; 47:111-128. [PMID: 22251211 DOI: 10.1080/03601234.2012.616779] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Polychlorinated azobenzenes (PCABs) can be found as contaminant by products in 3,4-dichloroaniline and its derivatives and in the herbicides Diuron, Linuron, Methazole, Neburon, Propanil and SWEP. Trans congeners of PCABs are physically and chemically more stable and so are environmentally relevant, when compared to unstable cis congeners. In this study, to fulfill gaps on environmentally relevant partitioning properties of PCABs, the values of n-octanol/water partition coefficients (log K(OW)) have been determined for 209 congeners of chloro-trans-azobenzene (Ct-AB) by means of quantitative structure-property relationship (QSPR) approach and artificial neural networks (ANN) predictive ability. The QSPR methods used based on geometry optimalization and quantum-chemical structural descriptors, which were computed on the level of density functional theory (DFT) using B3LYP functional and 6-311++G basis set in Gaussian 03 and of the semi-empirical quantum chemistry method (PM6) of the molecular orbital package (MOPAC). Polychlorinated dibenzo-p-dioxins (PCDDs), -furans (PCDFs) and -biphenyls (PCBs), to which PCABs are related, were reference compounds in this study. An experimentally obtained data on physical and chemical properties of PCDD/Fs and PCBs were reference data for ANN predictions of log K(OW) values of Ct-ABs in this study. Both calculation methods gave similar results in term of absolute log K(OW) values, while the models generated by PM6 are considered highly efficient in time spent, when compared to these by DFT. The estimated log K(OW) values of 209 Ct-ABs varied between 5.22-5.57 and 5.45-5.60 for Mono-, 5.56-6.00 and 5.59-6.07 for Di-, 5.89-6.56 and 5.91-6.46 for Tri-, 6.10-7.05 and 6.13-6.80 for Tetra-, 6.43-7.39 and 6.48-7.14 for Penta-, 6.61-7.78 and 6.98-7.42 for Hexa-, 7.41-7.94 and 7.34-7.86 for Hepta-, 7.99-8.17 and 7.72-8.20 for Octa-, 8.35-8.42 and 8.10-8.62 for NonaCt-ABs, and 8.52-8.60 and 8.81-8.83 for DecaCt-AB. These log K(OW) values shows that Ct-ABs are compounds of relatively low environmental mobility (log K(OW) > 4.5) and of significant bioaccumulation potential.
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Affiliation(s)
- Agata J Wilczyńska-Piliszek
- Research Group of Environmental Chemistry, Ecotoxicology & Food Toxicology, Institute of Environmental Sciences & Public Health, University of Gdańsk, Gdańsk, Poland
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Witt KL, Zeiger E, Tice RR, van Birgelen AP. The genetic toxicity of 3,3',4,4'-tetrachloroazobenzene and 3,3',4, 4'-tetrachloroazoxybenzene: discordance between acute mouse bone marrow and subchronic mouse peripheral blood micronucleus test results. Mutat Res 2000; 472:147-54. [PMID: 11113707 DOI: 10.1016/s1383-5718(00)00143-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
3,3',4,4'-Tetrachloroazobenzene (TCAB) and 3,3',4, 4'-tetrachloroazoxybenzene (TCAOB) are dioxin-like chemicals that were investigated for toxicity in 13-week gavage studies in male and female B6C3F(1) mice and F344N rats by the National Toxicology Program. As part of the comprehensive toxicological investigation of these chemicals, peripheral blood smears from mice treated 5 days per week for 13 weeks with 0.1-30mg/kg/day TCAB or TCAOB were analyzed for the frequency of micronucleated (MN) normochromatic erythrocytes (NCE). Both chemicals produced significant increases in MN-NCE in male and female mice. In contrast to these positive results in subchronic exposure studies, no significant increases were seen in acute bone marrow MN tests in male mice administered three daily injections of 50-200mg/kg/day TCAB and TCAOB. The results with TCAB and TCAOB suggest that the routine integration of MN tests with subchronic toxicity studies may allow detection of mutagenic activity for some chemicals that fail to elicit responses in short-term, high dose tests. In addition, the integration of mutagenicity tests into general toxicity tests reduces the use of laboratory animals and the cost of the testing.
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Affiliation(s)
- K L Witt
- ILS Inc., P.O. Box 13501, Research Triangle Park, NC 27709, USA.
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Whysner J, Williams GM. 2,3,7,8-Tetrachlorodibenzo-p-dioxin mechanistic data and risk assessment: gene regulation, cytotoxicity, enhanced cell proliferation, and tumor promotion. Pharmacol Ther 1996; 71:193-223. [PMID: 8910955 DOI: 10.1016/0163-7258(96)00068-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been found to cause several tumor types in rodents, but TCDD has not been proven to cause cancer in humans, although there have been reported associations. TCDD does not bind to DNA, and indirect tests for DNA damage have been mostly negative. Tumorigenicity by TCDD in rodents has been linked to cellular necrosis, enhanced cell proliferation and tumor promotion. TCDD binds to the Ah receptor, which induces CYP1A1. This binding may be involved in tumorigenicity in rodents; however, additional TCDD-induced toxic changes appear to be required. Biopersistence and organ distribution may play an important role in TCDD dosage extrapolation to humans, but these have not been adequately determined.
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Affiliation(s)
- J Whysner
- Toxicology and Risk Assessment Program, American Health Foundation, Valhalla, NY 10595-1599, USA
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Čerňáková M. Effect of the insecticide nerametrine EK-15 on the activity of soil microorganisms. Folia Microbiol (Praha) 1993. [DOI: 10.1007/bf02898603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Skene SA, Dewhurst IC, Greenberg M. Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans: the risks to human health. A review. HUMAN TOXICOLOGY 1989; 8:173-203. [PMID: 2663703 DOI: 10.1177/096032718900800301] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
1 PCDDs and PCDFs are ubiquitous and persistent in the environment. They are to be found in body tissues of both humans and animals. 2 The most extensively studied PCDD is 2,3,7,8-TCDD. It has been shown to produce a wide range of effects and is considered to be a (non-genotoxic) carcinogen in animals. 3 Studies into the mechanisms of toxicity so far reveal that there is involvement of a specific receptor (Ah), however further work is required to elucidate the mechanisms of the various effects. 4 Reports on a number of human exposures to PCDDs and PCDFs are described. Results from human epidemiological studies are difficult to interpret: there have been problems in methodology; there has been inadequate information on intake, and exposures have often been to mixtures of PCDDs and/or PCDFs together with other related compounds. 5 Many regulatory authorities faced with the problem of providing an index of risk from exposure to mixtures of PCDDs and PCDFs have employed the concept of 'TCDD equivalents'. 6 Whether or not PCDDs and PCDFs pose a significant human health risk at current levels of exposure they remain of considerable interest to the toxicologist.
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Affiliation(s)
- S A Skene
- Department of Health, Medical Toxicology, London, UK
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Abstract
Recently, monochlorodibenzofuran, which is formed by the reaction of dibenzofuran with residual chlorine, has been detected in tap water in one region of Japan. The mutagenicities of 1-, 2-, 3-, and 4-chlorodibenzofuran were tested using Salmonella typhimurium TA98 and TA100. 1-Chlorodibenzofuran and 4-chlorodibenzofuran proved to be practically non-mutagenic, while 2-chlorodibenzofuran was weakly mutagenic. Unlike these three isomers, 3-chlorodibenzofuran was markedly mutagenic, and the intensity of its mutagenicity in TA98 was about one-fifth and in TA100 about one-twentieth of that of benzo[a]pyrene.
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Affiliation(s)
- M Matsumoto
- Environmental Health Sciences Division, National Institute for Environmental Studies, Ibaraki, Japan
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Shu HP, Paustenbach DJ, Murray FJ. A critical evaluation of the use of mutagenesis, carcinogenesis, and tumor promotion data in a cancer risk assessment of 2,3,7,8-tetrachlorodibenzo-p-dioxin. Regul Toxicol Pharmacol 1987; 7:57-88. [PMID: 3575798 DOI: 10.1016/0273-2300(87)90048-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Regulatory agencies in the Western Hemisphere are currently assessing the potential human health risks of environmental contamination by 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD). Some U.S. agencies such as the Environmental Protection Agency (EPA) and Centers for Disease Control (CDC) have assumed that TCDD behaves as a tumor initiator in animals and have used linear low-dose mathematical extrapolation models for estimating any human risk. In contrast, the Ontario Ministry of the Environment, the State Institute of National Health of The Netherlands, and the Federal Environmental Agency of the Federal Republic of Germany have concluded that TCDD does not have initiator activity; these agencies have advocated a risk extrapolation approach which applies a safety factor to a no-observable-effect level. Estimations of the potential risk obtained by these two approaches can differ by three to four orders of magnitude and have a major impact on the allocation of resources within the affected countries. This paper critically reviews the TCDD bacterial, animal, and human data on mutagenesis, carcinogenesis, and tumor promotion and concludes that the scientific evidence does not support risk estimations which are based on TCDD as a tumor initiator. Rather, the animal data overwhelmingly support TCDD as a tumor promoter. Risk estimations which incorporate tumor promotion activity more accurately reflect the scientific understanding of TCDD's mechanism of action and provide better estimates of its risk.
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Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin is one of the most toxic and highly stable compounds known in the environment. Due to uncontrolled exothermic reactions during manufacture of 2,4,5-T and other chlorophenoxy compounds, TCDD is released in the environment. The importance of determining the hazards to human health from dioxin became apparent because of its severe adverse health effects. 'Agent Orange' which is a mixture of 2,4,5-T and 2,4-D has been extensively used during the late Vietnam War. In this review an attempt has been made to evaluate the mutagenic and genotoxic effects of 2,3,7,8-TCDD as known at present.
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Combes RD, Haveland-Smith RB. A review of the genotoxicity of food, drug and cosmetic colours and other azo, triphenylmethane and xanthene dyes. Mutat Res 1982; 98:101-248. [PMID: 7043261 DOI: 10.1016/0165-1110(82)90015-x] [Citation(s) in RCA: 240] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The genetic toxicology of the major dyestuffs used in foods, drugs and cosmetics has been reviewed. Published data for azo, triphenylmethane and xanthene dyes from short-term assays for muta-carcinogenicity have been summarized and discussed according to usage, current and previous worldwide legislative status. Certain other synthetic food dyes, commercial mixtures, natural and polymeric colourants as well as a section on aminoazobenzene and its derivatives have been included. Genotoxicity has been discussed with reference to structural chemistry, levels of exposure, absorption and metabolism and to epidemiological information. The extent of agreement between data from different tests and correlations with animal cancer assays have been considered. Synthetic dyes from the 3 major structural classes exhibit genotoxicity, whilst only 2 natural colours have proved active. Activity may be due to the presence of certain functional groups, notably nitro- and amino-substituents which are metabolized to ultimate electrophiles that may be stabilized by electronic interaction with aryl rings. Metabolic processes such as azo-reduction may be activating or detoxifying. the low but significant correlation between animal carcinogenicity and short-term test data may be increased with further screening, especially involving chromosome assays. It is suggested that a human cancer hazard may exist where significant quantities of finished benzidine dye samples are handled. Such risks from exposures to other colours and the possibility of human germ-line mutation induction by dyestuffs cannot be meaningfully assessed.
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