Table of Contents
ISRN Toxicology
Volume 2013 (2013), Article ID 230763, 10 pages
Research Article

Reduced Life Expectancy Model for Effects of Long Term Exposure on Lethal Toxicity with Fish

1Griffith School of Engineering, Griffith University, Nathan Campus, Brisbane, Queensland 4111, Australia
2Griffith School of Environment, Griffith University, Nathan Campus, Brisbane, Queensland 4111, Australia

Received 29 August 2013; Accepted 29 October 2013

Academic Editors: M. Pacheco and S. M. Waliszewski

Copyright © 2013 Vibha Verma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A model based on the concept of reduction in life expectancy (RLE model) as a result of long term exposure to toxicant has been developed which has normal life expectancy (NLT) as a fixed limiting point for a species. The model is based on the equation (LC50 = a ln(LT50) + b) where a and b are constants. It was evaluated by plotting ln LT50 against LC50 with data on organic toxicants obtained from the scientific literature. Linear relationships between LC50 and ln LT50 were obtained and a Calculated NLT was derived from the plots. The Calculated NLT obtained was in good agreement with the Reported NLT obtained from the literature. Estimation of toxicity at any exposure time and concentration is possible using the model. The use of NLT as a reference point is important since it provides a data point independent of the toxicity data set and limits the data to the range where toxicity occurs. This novel approach, which represents a departure from Haber's rule, can be used to estimate long term toxicity from limited available acute toxicity data for fish exposed to organic biocides.