Jager Tjalling, Crommentuijn Trudie, van Gestel Cornelis A M, Kooijman Sebastiaan A L M
Department of Theoretical Biology, Vrije Universiteit, de Boelelaan 1085, NL-1081 HV, Amsterdam, The Netherlands.
Environ Sci Technol. 2004 May 15;38(10):2894-900. doi: 10.1021/es0352348.
Standard toxicity tests do not allow extrapolations to the population level, mainly because these tests apply a short, fixed exposure time and focus on a single end point only. These limitations can be overcome by (partial) life-cycle toxicity testing, although these test results are harder to analyze. DEBtox is an existing software tool for the process-based analysis of standardized bioassays, and this paper presents two extensions of this method, making it applicable to life-cycle tests: the simultaneous assessment of end points and the description of aging (senescence) of the animals. We demonstrate these adaptations by describing life-cycle tests with the springtail Folsomia candida, exposed to cadmium and triphenyltin in their food. The extended model is able to describe the data for all end points simultaneously overtime with few, physiologically relevant parameters. Furthermore, the analysis reveals these chemicals to have distinctly different modes of action: cadmium apparently decreases the assimilation of energy from the food whereas triphenyltin increases the maintenance costs. The model fit allows calculation of the intrinsic rate of population increase, integrating effects on survival and reproduction. As the analysis is process based, population responses under food limitation can be explored, which depends critically on the selected mode of action.
标准毒性试验无法外推至种群水平，主要原因是这些试验采用的是短时间、固定的暴露时间，且仅关注单一终点。（部分）生命周期毒性试验可以克服这些局限性，尽管这些试验结果更难分析。DEBtox是一种用于标准化生物测定基于过程分析的现有软件工具，本文介绍了该方法的两个扩展，使其适用于生命周期试验：终点的同时评估和动物衰老（老化）的描述。我们通过描述用跳虫弗氏伪长角跳虫进行的生命周期试验来展示这些适应性，该跳虫在食物中接触镉和三苯基锡。扩展模型能够用很少的、生理相关的参数同时随时间描述所有终点的数据。此外，分析表明这些化学物质具有明显不同的作用模式：镉显然会降低从食物中同化能量的能力，而三苯基锡会增加维持成本。模型拟合允许计算种群内在增长率，整合对生存和繁殖的影响。由于分析是基于过程的，因此可以探索食物限制下的种群反应，这在很大程度上取决于所选的作用模式。
