Silver nanoparticles (Ag-NPs) streamed into aquatic environments are chemically transformed into various forms, and one of the predominant forms is silver sulfide NPs (Ag₂S-NPs). Because of the lower dissolution rate of silver ions (Ag⁺), the toxicity of Ag₂S-NPs could be lower than that of Ag-NPs. However, the toxicity of Ag₂S-NPs has been observed to be restored under oxidative or acidic conditions. In the present study, 4 aquatic organisms, Pseudokirchneriella subcapitata (algae), Daphnia magna (crustacean), Danio rerio (fish), and Hydra vulgaris (cnidarian), were exposed to Ag₂S-NPs transformed from Ag-NPs using Na₂S under anoxic conditions; and acute toxicity was evaluated. The acute toxicity of Ag₂S-NPs was rarely observed in algae, crustaceans, and fish, whereas it was significantly restored in cnidarians. Although the dissolution rate was low in the medium exposed to Ag₂S-NPs, high Ag⁺ was detected in H. vulgaris. To understand the mechanisms of Ag₂S-NP toxicity in cnidarians, transcriptional profiles of H. vulgaris exposed to Ag-NPs, Ag₂S-NPs, and AgNO₃ were analyzed. As a result, most of the genes that were significantly changed in the Ag₂S-NPs group were also found to be significantly changed in the AgNO₃ group, indicating that the toxicity of Ag₂S-NPs was caused by Ag⁺ dissolved by the acidic condition in the gastrovascular cavity of H. vulgaris. This finding is the first in an aquatic organism and suggests the need to reconsider the stability and safety of Ag₂S-NPs in the aquatic environment. Environ Toxicol Chem 2021;40:1662–1672. © 2021 SETAC

中文翻译：

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银离子在长蛇的胃肠腔内加速释放增加了硫化银纳米颗粒的毒性

流入水生环境的银纳米粒子 (Ag-NPs) 被化学转化为各种形式，其中一种主要形式是硫化银纳米粒子 (Ag ₂ S-NPs)。由于银离子（Ag ^{+ ）的溶解速率较低，Ag} ₂ S-NPs的毒性可能低于 Ag-NPs。然而，已观察到Ag _{2 S-NPs 的毒性在氧化或酸性条件下会恢复。}在本研究中，4 种水生生物，即Pseudokirchneriella subcapitata（藻类）、Daphnia magna（甲壳类动物）、Danio rerio（鱼）和Hydra vulgaris（刺胞动物）暴露于 Ag ₂在缺氧条件下使用 Na ₂ S由 Ag-NPs 转化而成的 S-NPs ；并评估了急性毒性。Ag ₂ S-NPs 的急性毒性在藻类、甲壳类动物和鱼类中很少观察到，而在刺胞动物中则显着恢复。尽管在暴露于 Ag ₂ S-NPs的介质中溶出速率较低，但在H. vulgaris中检测到高 Ag ⁺。为了解 Ag ₂ S-NP 在刺胞动物中的毒性机制，分析了暴露于 Ag-NPs、Ag ₂ S-NPs 和 AgNO _3的普通普通人的转录谱。结果，大多数在 Ag _{2中发生显着变化的基因S-NPs组在AgNO 3}组中也有明显的变化，说明Ag ₂ S-NPs的毒性是由于Ag ^+在寻常嗜血杆菌胃血管腔内被酸性条件溶解所致。这一发现是水生生物中的第一个发现，表明需要重新考虑 Ag ₂ S-NPs 在水生环境中的稳定性和安全性。环境毒物化学2021；40:1662–1672。© 2021 SETAC