Faculty of Science, C3, University of Technology, Sydney, P.O. Box 123, Broadway, NSW, 2007, Australia.
Australian Nuclear Science & Technology Organisation, Lucas Heights, NSW, Australia.
J Environ Radioact. 2017 Nov;178-179:430-438. doi: 10.1016/j.jenvrad.2017.02.005. Epub 2017 Mar 21.
This study compared the bioaccumulation of anthropogenic nuclides (Zn, Cs, Co and Am) between the egg and juvenile life stages of a small shark (Scyliorhinus canicula), based on previously published experimental data. Rates of accumulation over 15 days were derived and summed for the transfer pathways which were specific to these two life stages. Radionuclide transfers to the egg and its embryo & yolk were quantified for i) the maternal pathway following her uptake of radionuclides via food and seawater and ii) from seawater following its oviposition. For the juvenile, the transfer of radionuclides were measured for aqueous & dietary pathways. The results show that, compared to juveniles, eggs have equivalent rates of accumulation of Zn and Cs but enhanced accumulation of Am by a factor of five and of Co by two orders of magnitude. The radiological exposure of the embryo due to radionuclides maternally transferred to the embryo & yolk is also enhanced for the alpha-emitting Am. This enhanced accumulation of Am and Co, as well as the equivalent accumulation of Zn and Cs, suggest greater likely vulnerability to radiation damage in eggs as compared to juveniles. Radiological dose assessment confirmed highest doses to the egg which is predominantly due to accumulated Am.
本研究基于先前发表的实验数据，比较了小鲨鱼（Scyliorhinus canicula）卵和幼体阶段人为放射性核素（Zn、Cs、Co 和 Am）的生物累积。得出了 15 天内通过特定于这两个生命阶段的转移途径的积累率，并进行了总结。放射性核素向卵及其胚胎和卵黄的转移通过以下两种途径进行了量化：(i)母体通过食物和海水摄取放射性核素后，放射性核素在母体中的转移；(ii)卵母细胞产卵后，放射性核素从海水中的转移。对于幼体，测量了放射性核素在水相和饮食途径中的转移。结果表明，与幼体相比，卵具有相同的 Zn 和 Cs 积累率，但 Am 的积累率高五倍，Co 的积累率高两个数量级。母体转移到胚胎和卵黄中的放射性核素使胚胎的放射性暴露也增强，特别是α发射体 Am。Am 和 Co 的这种增强积累，以及 Zn 和 Cs 的等效积累，表明卵比幼体更有可能受到辐射损伤。辐射剂量评估证实，卵受到的剂量最高，这主要是由于积累的 Am 所致。
