Exposure medium and particle ageing moderate the toxicological effects of nanomaterials to Daphnia magna over multiple generations: a case for standard test review?
Exposure medium and particle ageing moderate the toxicological effects of nanomaterials to Daphnia magna over multiple generations: a case for standard test review?
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DOI：
10.1039/d0en00049c
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发表时间：
2020-04-01
影响因子：
7.3
通讯作者：
Lynch, Iseult
中科院分区：
文献类型：
--
作者：
Ellis, Laura-Jayne A.;Valsami-Jones, Eugenia;Lynch, Iseult
进入水环境的原始工程纳米材料(NMS)在其生命周期中通过化学、物理和/或生物过程发生老化。因此，在NMS出现之前为可溶化学品设计的传统生态毒理学测试使用原始的NMS和仅含盐的介质，这些介质不能代表现实的NM暴露情景。利用大型水蚤多世代研究探索了暴露介质和NM老化对NM毒性的影响，目的是确定Daphnia Magna是否适应持续暴露和/或只接受亲本暴露是否会在后续世代产生表观遗传效应。在标准的高硬度培养液和合成的欧洲V类低地水中，达夫类动物连续或仅由亲代暴露于原始和陈年的二氧化钛(二氧化钛)和银(银)纳米管中。标准培养液中的原始NMS的毒性后果最严重，暴露后两代均表现为负效应。在V类水中老化的NMS在持续和仅有父母接触的情况下，对所有世代的生长和寿命的总体毒性后果较少。总体而言，在没有与环境有关的介质和老化的NMS的情况下，标准化的水蚤测试目前高估了NM的毒性，并且没有考虑到对后续几代人的潜在影响。结果表明，更新标准检测以反映科学进步和增加利益相关者对监管的信任的重要性。
Pristine engineered nanomaterials (NMs) entering the aquatic environment become 'aged' during their lifetime via chemical, physical and/or biological process. Therefore, traditional ecotoxicology tests which were designed for soluble chemicals prior to the emergence of NMs, use pristine NMs and salt-only media which are not representative of realistic NM exposure scenarios. Exposure medium and NM ageing moderation of NM toxicity were explored using Daphnia magna multigenerational studies aiming to determine whether the daphnids adapted to continuous exposure and/or if parent-only exposure resulted in epigenetic effects in subsequent generations. Daphnids were continuously, or parent-only, exposed to pristine and aged titanium dioxide (TiO2) and silver (Ag) NMs, in a standard high hardness culture media and synthetic European Class V lowland water. Pristine NMs in the standard culture medium had the most severe toxic consequences, and displayed negative effects in two generations post exposure. NMs aged in the class V water had fewer overall toxic consequences on growth and longevity across all generations in both continuous and parent-only exposure scenarios. Overall, in the absence of environmentally relevant media and aged NMs, standardised Daphnia tests currently overestimate NM toxicity, and fail to consider potential impacts in subsequent generations. The results demonstrate the importance of updating standard testing to reflect scientific advances and increase stakeholder trust in regulation.