Department of Environmental Science, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark.
Environ Sci Technol. 2013 Jul 2;47(13):7020-7. doi: 10.1021/es3047813. Epub 2013 Mar 25.
A 7-day mixture toxicity experiment with the terrestrial springtail Folsomia candida was conducted, and the effects were linked to three different mixture exposure parameters. Passive dosing from silicone was applied to tightly control exposure levels and compositions of 12 mixture treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑C(lipid eq.)), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LC(lipid eq 50)) of 133 mmol kg(-1) lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture exposure in terms of both level and composition, while ∑a, ∑C(lipid eq.), and ∑TU allowed baseline toxicity to be linked to mixture exposure.
开展了为期 7 天的陆生跳虫 Folsomia candida 的混合物毒性实验，将其效果与三个不同的混合物暴露参数相关联。采用硅酮的被动给药来严格控制 12 种混合物处理的暴露水平和组成，这些混合物处理含有多环芳烃（PAHs）萘、菲和芘。然后将跳虫的致死率与总化学活性（∑a）、总平衡脂质浓度（∑C（lipid eq.））和总毒性单位（∑TU）联系起来。在每种情况下，所有 12 种混合物处理的效果都可以拟合到一个 sigmoidal 暴露-反应关系中。有效致死化学活性（La50）为 0.027，远低于基线毒性的 0.01-0.1 的预期范围。将效果与基于脂质的暴露参数联系起来，得到的有效致死浓度（LC（lipid eq 50））为 133mmolkg（-1）脂质，与基线毒性的致死膜负担（40-160mmolkg（-1）脂质）非常吻合。最后，有效致死毒性单位（LTU50）为 1.20，与预期值 1 非常接近。总之，被动给药在水平和组成方面都提供了严格控制的混合物暴露，而∑a、∑C（lipid eq.）和∑TU 则允许将基线毒性与混合物暴露联系起来。
