title: Evaluation of effects of long term exposure on lethal toxicity with mammals.
abstract: The relationship between exposure time (LT50) and lethal exposure concentration (LC50) has been evaluated over relatively long exposure times using a novel parameter, Normal Life Expectancy (NLT), as a long term toxicity point. The model equation, ln(LT50) = aLC50(ν) + b, where a, b and ν are constants, was evaluated by plotting lnLT50 against LC50 using available toxicity data based on inhalation exposure from 7 species of mammals. With each specific toxicant a single consistent relationship was observed for all mammals with ν always <1. Use of NLT as a long term toxicity point provided a valuable limiting point for long exposure times. With organic compounds, the Kow can be used to calculate the model constants a and v where these are unknown. The model can be used to characterise toxicity to specific mammals and then be extended to estimate toxicity at any exposure time with other mammals.
authors.affiliation: Griffith School of Engineering, Griffith University, Nathan Campus, Brisbane, Queensland 4111, Australia. Electronic address: v.verma@griffith.edu.au.
authors.forename: Vibha
authors.initials: V
authors.lastname: Verma
authors.affiliation: Griffith School of Engineering, Griffith University, Nathan Campus, Brisbane, Queensland 4111, Australia.
authors.forename: Qiming J
authors.initials: QJ
authors.lastname: Yu
authors.affiliation: Griffith School of Environment, Griffith University, Nathan Campus, Brisbane, Queensland 4111, Australia.
authors.forename: Des W
authors.initials: DW
authors.lastname: Connell
mesh_terms: D000818:Animals; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D004785:Environmental Pollutants / Q000032:analysis / Q000633:toxicity*; D007928:Lethal Dose 50; D008322:Mammals / Q000502:physiology*; D008954:Models, Biological; D018675:Toxicity Tests / Q000379:methods* / Q000592:standards
chemical_list: D004785:Environmental Pollutants
keywords: Body size of mammals; Long term toxicity; Normal life expectancy; Octanol–water partitioning coefficient; Reduced life expectancy model; Slope coefficient