Abstract The release of engineered nanomaterials (ENMs) into the environment is increasing at a rapid pace due to rising production and incorporation into a variety of consumer products, collectively referred to as nano-enabled products (NEPs). During the life cycle of the NEPs, ENMs can be released into aquatic environments. The ENMs released during the various life cycle stages are often not in their pristine form as they are transformed when they encounter physical, chemical and biological stressors. Upon release into the environment, it is highly likely that aquatic organisms would be exposed to these ENMs. The current review summarised recent literature on the toxicity effects of transformed ENMs and ENMs released from NEPs. The transformation processes of pristine ENMs, ENMs’ release from NEPs, and toxicity effects observations are discussed; the emphasis being on the toxic effects of non-pristine ENMs. The procedures used to transform pristine ENMs and release ENMs from NEPs can exert physicochemical alterations relative to the original state of the ENMs. Findings showed that significant uncertainty continues to exist on the toxicity of the non-pristine ENMs. The uncertainty can be attributed to a multitude of factors, more likely due to the lack of coordinated efforts and standardised testing protocols for transformation, release and toxicity that limit the availability of robust data on which solid risk assessments of ENMs can be based. Nonetheless, the overall literature herein indicated that the transformed ENMs tend to be relatively less toxic to aquatic biota compared to ENMs released from NEPs that are commonly associated with traces of the product matrix. The pronounced toxicity effects of ENMs released from NEPs is widely attributed to the: (i) ENMs, (ii) released product matrix, and (iii) dissolved ions, as such, the realistic risk assessment and environmental regulation of ENMs in isolation are thus hampered. The review ends by proposing various strategies that can be adopted to improve the data limitations that were identified.

中文翻译：

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转化和产品释放的工程纳米材料的水生毒性：当前知识状态概述

摘要 由于产量的增加和融入各种消费产品（统称为纳米产品 (NEP)），工程纳米材料 (ENM) 向环境中释放的速度正在迅速增加。在 NEP 的生命周期中，ENM 可以释放到水生环境中。在生命周期的各个阶段释放的 ENM 通常不是原始形式，因为它们在遇到物理、化学和生物压力时会发生转变。释放到环境中后，水生生物很可能会接触到这些 ENM。目前的综述总结了最近关于转化的 ENM 和从 NEP 释放的 ENM 毒性作用的文献。讨论了原始ENMs的转化过程、ENMs从NEPs中的释放以及毒性效应观察；重点是非原始 ENM 的毒性作用。用于转化原始 ENMs 和从 NEPs 释放 ENMs 的程序可以施加相对于 ENMs 原始状态的物理化学改变。研究结果表明，非原始 ENM 的毒性仍然存在很大的不确定性。不确定性可归因于多种因素，更有可能是由于缺乏针对转化、释放和毒性的协调努力和标准化测试协议，这限制了可用于 ENM 可靠风险评估的可靠数据的可用性。尽管如此，本文的整体文献表明，与从通常与痕量产品基质相关的 NEP 释放的 ENM 相比，转化的 ENM 对水生生物群的毒性相对较低。NEPs 释放的 ENMs 的显着毒性效应广泛归因于：(i) ENMs，(ii) 释放的产品基质，和 (iii) 溶解离子，因此，孤立的 ENMs 的现实风险评估和环境监管因此阻碍。审查最后提出了各种可用于改进已确定的数据局限性的策略。