Mayer Philipp, Holmstrup Martin
Department of Environmental Chemistry and Microbiology, National Environmental Research Institute, University of Aarhus, PO Box 358, DK-4000 Roskilde, Denmark.
Environ Sci Technol. 2008 Oct 1;42(19):7516-21. doi: 10.1021/es801689y.
The partitioning of organic soil pollutants into soil organisms is driven by their chemical activity, which normally does not exceed that of the pure pollutant. Passive dosing with the silicone poly(dimethylsiloxane) (PDMS) was used to initiate and maintain the maximum chemical activity of 10 polycyclic aromatic hydrocarbons (PAHs) in toxicity tests with the springtail Folsomia candida. The test animals could move freely on the PDMS saturated with PAHs, resulting in direct contact and exposure to saturated air. After 7 days, springtail lethality correlated neither with the octanol-water partition coefficients of the PAHs nor with their molecular size, but with their melting point All low-melting PAHs (T(M) < or = 110 degrees C) caused 100% lethality, whereas all high-melting PAHs (TM > or = 180 degrees C) caused no significant lethality. The lethality was successfully fitted to one chemical activity response curve for all PAHs tested, with effective chemical activity causing 50% lethality (Ea-50) of 0.058. It was also fitted to the PAH concentration in the PDMS, resulting in an EC(PDMS)-50 of 8.7 mM. Finally, the combined exposure to anthracene and pyrene was described by the sum of chemical activities causing lethality, in good agreement with the chemical activity-response curve obtained.
有机土壤污染物在土壤生物体内的分配受其化学活性驱动，该化学活性通常不超过纯污染物的化学活性。在对弹尾虫（Folsomia candida）进行的毒性试验中，采用聚二甲基硅氧烷（PDMS）被动给药来引发并维持10种多环芳烃（PAHs）的最大化学活性。试验动物可在被PAHs饱和的PDMS上自由移动，从而直接接触并暴露于饱和空气中。7天后，弹尾虫的致死率既与PAHs的正辛醇 - 水分配系数无关，也与其分子大小无关，而是与其熔点有关。所有低熔点PAHs（T(M)≤110℃）导致100%的致死率，而所有高熔点PAHs（TM≥180℃）未导致显著致死率。对于所有测试的PAHs，致死率成功拟合为一条化学活性响应曲线，导致50%致死率的有效化学活性（Ea - 50）为0.058。它也拟合了PDMS中PAH的浓度，得出EC(PDMS)-50为8.7 mM。最后，蒽和芘的联合暴露通过导致致死率的化学活性总和来描述，与所获得的化学活性 - 响应曲线高度吻合。
