Jeffree Ross A, Oberhaensli Francois, Teyssie Jean-Louis, Fowler Scott W
IAEA Environment Laboratories, 4 Quai Antoine, MC 98000, Monaco.
IAEA Environment Laboratories, 4 Quai Antoine, MC 98000, Monaco.
J Environ Radioact. 2018 Dec;192:573-579. doi: 10.1016/j.jenvrad.2018.05.002. Epub 2018 May 26.
Cartilaginous dogfish Scyliorhinus canicula continued to transfer four anthropogenic radionuclides (Zn, Co, Cs and Am) to their eggs for over six months, after two months of continued maternal exposure to radio-labelled food. Unexpectedly, rates of radionuclide transfers to eggs and their yolk & embryo during maternal depuration were equivalent for Co and Am, or even enhanced for Zn and Cs by factors of c.200-350%, over two-three months, compared to their maximal transfer rates at the end of the maternal uptake phase. These rates of maternal transfer of radionuclides to yolk & embryo were positively associated with their previously determined efficiencies of assimilation (AE) from ingested radio-labelled food. Thus progeny may be more exposed via maternal transfer to those radionuclides which have greater rates of maternal assimilation from food. As maternal depuration continued beyond 60-80 up to 180-200 days the transfers of all four radionuclides to eggs did diminish but were still substantial at mean values of 18% for Am, 17% for Cs and 9 and 8% for Co and Zn, respectively. In the yolk & embryo the mean rates of transfer over this period were further reduced for Am (13.5%), Co (2.5%) and Zn (5.8%), but were still appreciable for Cs at 56%. These results for S. canicula have demonstrated a potential enhanced radiological risk of extended duration due to the particular biokinetics of maternal transfer in this species. This study draws further attention to the current paucity of knowledge about the maternal: progeny transfer pathway, particularly in the context of the known heightened radio-sensitivity of early life stages in fish and other vertebrates, compared to later life stages.
在母体持续接触放射性标记食物两个月后，软骨鲨（Scyliorhinus canicula）在长达六个多月的时间里持续将四种人为放射性核素（锌、钴、铯和镅）转移到它们的卵中。出乎意料的是，在母体净化的两到三个月期间，钴和镅向卵及其卵黄和胚胎的放射性核素转移率相当，锌和铯的转移率甚至比母体摄取阶段结束时的最大转移率提高了约200 - 350%。这些放射性核素从母体向卵黄和胚胎的转移率与它们先前测定的从摄入的放射性标记食物中的同化效率（AE）呈正相关。因此，后代可能通过母体转移而更多地接触到那些从食物中母体同化率更高的放射性核素。随着母体净化持续超过60 - 80天直至180 - 200天，所有四种放射性核素向卵的转移确实减少了，但镅、铯、钴和锌的平均值仍分别高达18%、17%、9%和8%，仍然相当可观。在此期间，卵黄和胚胎中的平均转移率对于镅（13.5%）、钴（2.5%）和锌（5.8%）进一步降低，但铯仍高达56%，仍然相当可观。软骨鲨的这些结果表明，由于该物种母体转移的特殊生物动力学，存在延长持续时间的潜在更高辐射风险。这项研究进一步提醒人们注意目前关于母体 - 后代转移途径的知识匮乏，特别是在已知鱼类和其他脊椎动物早期生命阶段比后期生命阶段对辐射更敏感的背景下。
