Sánchez-Bayo Francisco
Department of Environmental Sciences, Centre for Ecotoxicology, University of Technology-Sydney, C/-P.O. Box 29, Lidcombe, NSW 1825, Australia.
Ecotoxicology. 2009 Apr;18(3):343-54. doi: 10.1007/s10646-008-0290-1. Epub 2008 Dec 17.
The ability to predict the effects of toxicants in organisms with reasonable accuracy depends to a great extent on the toxico-kinetic models used to describe such effects. Toxic effects of organic chemicals and heavy metals have been described adequately using a hyperbolic model that considers the concentration of the toxicant and the time of exposure only. Such a model relies on the median time to effect (ET(50)) of a chemical to estimate effects at any exposure time, but cannot make predictions for concentrations other than those tested experimentally. A complementary log-to-log model can calculate all ET(50) values for a toxicant, thus enabling the hyperbolic model to predict any level of effect for any combination of concentrations and times of exposure. The parameter values used in both models are obtained from experimental bioassays where the time-to-effect of a toxicant is recorded regularly in addition to standard acute or chronic toxicity data. These models will facilitate the risk assessment of chemicals by (1) predicting effects under any combination of time and concentrations, and (2) reducing to a minimum the experimental efforts required to obtain comprehensive ecotoxicity data.
能够以合理的准确度预测有毒物质对生物体的影响在很大程度上取决于用于描述此类影响的毒物动力学模型。使用仅考虑有毒物质浓度和暴露时间的双曲线模型已充分描述了有机化学品和重金属的毒性作用。这样的模型依靠化学品的半数效应时间(ET(50))来估计任何暴露时间的影响,但对于实验测试浓度以外的浓度无法进行预测。一个互补的双对数模型可以计算一种有毒物质的所有ET(50)值,从而使双曲线模型能够预测任何浓度和暴露时间组合下的任何效应水平。两个模型中使用的参数值均来自实验生物测定,在该测定中,除了标准急性或慢性毒性数据外,还定期记录有毒物质的效应时间。这些模型将通过以下方式促进化学品的风险评估:(1)预测任何时间和浓度组合下的效应,以及(2)将获取全面生态毒性数据所需的实验工作量降至最低。