Evaluation of time-dependent toxicity and combined effects for a series of mono-halogenated acetonitrile-containing binary mixtures

Mixture and time-dependent toxicity (TDT) was assessed for a series of mono-halogenated acetonitrile-containing combinations. Inhibition of bioluminescence in Aliivibrio fischeri was measured after 15, 30 and 45-min of exposure. Concentration-response (x/y) curves were determined for each chemical a...

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Main Authors: Douglas A. Dawson, Daphne Guinn, Gerald Pöch
Format: Article
Language:English
Published: Elsevier 2016-01-01
Series:Toxicology Reports
Online Access:http://www.sciencedirect.com/science/article/pii/S2214750016300518
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spelling doaj-a2389123e57f4540ab55e1ba98e681bd2020-11-24T21:55:20ZengElsevierToxicology Reports2214-75002016-01-013572583Evaluation of time-dependent toxicity and combined effects for a series of mono-halogenated acetonitrile-containing binary mixturesDouglas A. Dawson0Daphne Guinn1Gerald Pöch2Department of Biology/Toxicology, Ashland University, Ashland, OH, USA; Corresponding author.Department of Biology/Toxicology, Ashland University, Ashland, OH, USADepartment of Pharmacology and Toxicology, University of Graz, Graz, AustriaMixture and time-dependent toxicity (TDT) was assessed for a series of mono-halogenated acetonitrile-containing combinations. Inhibition of bioluminescence in Aliivibrio fischeri was measured after 15, 30 and 45-min of exposure. Concentration-response (x/y) curves were determined for each chemical alone at each timepoint, and used to develop predicted x/y curves for the dose-addition and independence models of combined effect. The x/y data for each binary mixture was then evaluated against the predicted mixture curves. Two metrics of mixture toxicity were calculated per combined effect model: (1) an EC50-based dose-addition (AQ) or independence (IQ) quotient and (2) the mixture/dose-addition (MX/DA) and mixture/independence (MX/I) metrics. For each single chemical and mixture tested, TDT was also calculated. After 45-min of exposure, 25 of 67 mixtures produced curves that were consistent with dose-addition using the MX/DA metric, with the other 42 being less toxic than predicted by MX/DA. Some mixtures had toxicity that was consistent with both dose-addition and independence. In general, those that were less toxic than predicted for dose-addition were also less toxic than predicted for independence. Of the 25 combinations that were consistent with dose-addition, 22 (88%) mixtures contained chemicals for which the individual TDT values were both >80%. In contrast, of the 42 non-dose-additive combinations, only 2 (4.8%) of the mixtures had both chemicals with individual TDT values >80%. The results support previous findings that TDT determinations can be useful for predicting chemical mixture toxicity. Keywords: Microtox®, Acute toxicity, Dose-addition, Independencehttp://www.sciencedirect.com/science/article/pii/S2214750016300518
collection DOAJ
language English
format Article
sources DOAJ
author Douglas A. Dawson
Daphne Guinn
Gerald Pöch
spellingShingle Douglas A. Dawson
Daphne Guinn
Gerald Pöch
Evaluation of time-dependent toxicity and combined effects for a series of mono-halogenated acetonitrile-containing binary mixtures
Toxicology Reports
author_facet Douglas A. Dawson
Daphne Guinn
Gerald Pöch
author_sort Douglas A. Dawson
title Evaluation of time-dependent toxicity and combined effects for a series of mono-halogenated acetonitrile-containing binary mixtures
title_short Evaluation of time-dependent toxicity and combined effects for a series of mono-halogenated acetonitrile-containing binary mixtures
title_full Evaluation of time-dependent toxicity and combined effects for a series of mono-halogenated acetonitrile-containing binary mixtures
title_fullStr Evaluation of time-dependent toxicity and combined effects for a series of mono-halogenated acetonitrile-containing binary mixtures
title_full_unstemmed Evaluation of time-dependent toxicity and combined effects for a series of mono-halogenated acetonitrile-containing binary mixtures
title_sort evaluation of time-dependent toxicity and combined effects for a series of mono-halogenated acetonitrile-containing binary mixtures
publisher Elsevier
series Toxicology Reports
issn 2214-7500
publishDate 2016-01-01
description Mixture and time-dependent toxicity (TDT) was assessed for a series of mono-halogenated acetonitrile-containing combinations. Inhibition of bioluminescence in Aliivibrio fischeri was measured after 15, 30 and 45-min of exposure. Concentration-response (x/y) curves were determined for each chemical alone at each timepoint, and used to develop predicted x/y curves for the dose-addition and independence models of combined effect. The x/y data for each binary mixture was then evaluated against the predicted mixture curves. Two metrics of mixture toxicity were calculated per combined effect model: (1) an EC50-based dose-addition (AQ) or independence (IQ) quotient and (2) the mixture/dose-addition (MX/DA) and mixture/independence (MX/I) metrics. For each single chemical and mixture tested, TDT was also calculated. After 45-min of exposure, 25 of 67 mixtures produced curves that were consistent with dose-addition using the MX/DA metric, with the other 42 being less toxic than predicted by MX/DA. Some mixtures had toxicity that was consistent with both dose-addition and independence. In general, those that were less toxic than predicted for dose-addition were also less toxic than predicted for independence. Of the 25 combinations that were consistent with dose-addition, 22 (88%) mixtures contained chemicals for which the individual TDT values were both >80%. In contrast, of the 42 non-dose-additive combinations, only 2 (4.8%) of the mixtures had both chemicals with individual TDT values >80%. The results support previous findings that TDT determinations can be useful for predicting chemical mixture toxicity. Keywords: Microtox®, Acute toxicity, Dose-addition, Independence
url http://www.sciencedirect.com/science/article/pii/S2214750016300518
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