Holmstrup Martin, Aubail Aurore, Damgaard Christian
National Environmental Research Institute, University of Aarhus, Department of Terrestrial Ecology, Vejlsøvej 25, DK-8600 Silkeborg, Denmark.
Comp Biochem Physiol C Toxicol Pharmacol. 2008 Aug;148(2):172-7. doi: 10.1016/j.cbpc.2008.05.003. Epub 2008 May 15.
We investigated how mercury (Hg) as an example of a widespread pollutant, can influence the tolerance of low temperature stress in the springtail, Folsomia candida. Springtails were exposed to aqueous solutions with a range of concentrations of HgCl2 and subsequently exposed to a range of low temperatures (cold shock) in order to model the dose-response surface (using survival as toxicity parameter). The data fitted a multiplicative model well (R2=0.99), and there was a highly significant synergistic interaction between Hg and cold shock. Our results indicate that the assessment of the toxicity of Hg by traditional laboratory studies where test organisms are exposed to only one stress factor and otherwise optimal conditions, may well underestimate the impact of the pollutant on the survival of field populations if stressful climatic conditions prevail. This conclusion is likely to apply to many other species and possibly other toxic chemicals as well. We propose that the present and similar research is needed for improvement of the scientific basis for setting safety factors in sound risk assessment of polluting chemicals.
我们以汞（Hg）作为一种广泛存在的污染物为例，研究了其如何影响跳虫（Folsomia candida）对低温胁迫的耐受性。将跳虫暴露于一系列不同浓度的HgCl₂水溶液中，随后再使其暴露于一系列低温环境（冷休克）中，以此构建剂量反应曲面（以存活率作为毒性参数）。数据与乘法模型拟合良好（R² = 0.99），汞与冷休克之间存在高度显著的协同相互作用。我们的研究结果表明，在传统实验室研究中，仅让受试生物暴露于单一胁迫因素且其他条件均为最佳条件下评估汞的毒性，如果恶劣气候条件普遍存在，很可能会低估污染物对野外种群生存的影响。这一结论可能适用于许多其他物种，也可能适用于其他有毒化学物质。我们建议，需要开展当前及类似研究，以完善在对污染化学品进行合理风险评估时设定安全系数的科学依据。
