title: The time-dependent synergism of the six-component mixtures of substituted phenols, pesticides and ionic liquids to Caenorhabditis elegans.
abstract: Traditional environmental risk assessment rarely focused on exposures to multi-component mixtures which may cause toxicological interactions and usually ignored that toxicity is a process in time, which may underestimate the environment risk of mixtures. In this paper, six chemicals belonging to three categories, two substituted phenols, two pesticides and two Ionic liquids, were picked to construct a six-component mixture system. To systematically examine the effects of various concentration compositions, the uniform design ray method was employed to design nine mixture rays with nine mixture ratios and for every mixture ray 12 concentration levels were specified by the fixed ratio ray design. The improved combination index was used to evaluate the combined toxicities of the mixtures to Caenorhabditis elegans (C. elegans) in the exposure times of 6, 12 and 24h. It was shown that the mixture rays display time-dependent synergism, i.e. the range of synergistic effect narrows and the strength of synergism runs down with exposure time, which illustrates that the mixture toxicity of some chemicals is not a sum of individual toxicities at some exposure times and it is necessary to consider the toxicological interaction in mixtures.
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Li
authors.initials: L
authors.lastname: Feng
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: ssliuhl@263.net.
authors.forename: Shu-Shen
authors.initials: SS
authors.lastname: Liu
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Li
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Han-Xiao
authors.initials: HX
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Hai-Ling
authors.initials: HL
authors.lastname: Liu
mesh_terms: D000465:Algorithms; D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects*; D045424:Complex Mixtures / Q000633:toxicity*; D004357:Drug Synergism; D004785:Environmental Pollutants / Q000633:toxicity; D052578:Ionic Liquids / Q000633:toxicity*; D007928:Lethal Dose 50; D010575:Pesticides / Q000633:toxicity*; D010636:Phenols / Q000633:toxicity*; D013997:Time Factors
chemical_list: D045424:Complex Mixtures; D004785:Environmental Pollutants; D052578:Ionic Liquids; D010575:Pesticides; D010636:Phenols
keywords: Combined toxicity; Data autoscaling; Mixture design; Multiple-component mixture; Time-dependent toxicity