Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
Amsterdam Institute for Life and Environment (A-LIFE), Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands.
Ecotoxicol Environ Saf. 2023 Mar 1;252:114599. doi: 10.1016/j.ecoenv.2023.114599. Epub 2023 Feb 3.
Silver (Ag) is one of the most used elements in the nanomaterials (NMs) form, which upon release to the environment can be harmful to organisms. We compared the toxicokinetics (TK) and toxicodynamics (TD) of Ag from AgNO (0, 15, 45, 135, 405 mg Ag/kg soil) and AgNM300K (0, 75, 150, 300, 600, 1200 mg Ag/kg soil) in the model organism Enchytraeus crypticus. Organisms were exposed in LUFA 2.2 soil, and besides body Ag concentrations, survival and reproduction were determined, in a time series (for 21 days). In the soil, the available (CaCl extractable) Ag fraction from Ag NM300K increased from 0 to 21 days but did not consistently change for AgNO. Internal concentrations reached equilibrium in most exposures to both Ag forms. The organisms were able to internalize and eliminate Ag, but less when exposed to Ag NM300K. The overall uptake rate constants for Ag from AgNO and Ag NM300K exposures were 0.05 and 0.06 kg soil/kg organism/day, respectively, the elimination rate constants 0.2 and 0.1 day, respectively. For AgNO the median lethal concentrations decreased steadily with time, while for Ag NM300K they remained constant during the first 10 days of exposure followed by a 2-fold decline in the last 7 days. The 21-d LC50s for both Ag forms were similar but the LC50 (based on internal concentrations) were 63 and 121 mg Ag/kg body DW (Dry Weight) for AgNO and Ag NM300K, respectively, showing higher toxicity of AgNO. These results show the importance of assessing time to toxicity, a relevant factor in toxicity assessment, especially for NMs.
银（Ag）是纳米材料（NMs）中使用最广泛的元素之一，释放到环境中后可能对生物体造成危害。我们比较了硝酸银（AgNO）（0、15、45、135、405 mg Ag/kg 土壤）和 AgNM300K（0、75、150、300、600、1200 mg Ag/kg 土壤）在模式生物赤子爱胜蚓（Enchytraeus crypticus）中的毒代动力学（TK）和毒效动力学（TD）。生物体在 LUFA 2.2 土壤中暴露，除了测定身体 Ag 浓度外，还在时间序列（21 天）中测定了存活率和繁殖率。在土壤中，AgNM300K 的可利用（CaCl 可提取）Ag 分数从 0 天增加到 21 天，但 AgNO 则没有持续变化。两种 Ag 形式的内部浓度都达到了平衡。生物体能够内化和消除 Ag，但暴露于 AgNM300K 时则较少。AgNO 和 AgNM300K 暴露的 Ag 总摄取率常数分别为 0.05 和 0.06 kg 土壤/kg 生物体/天，消除率常数分别为 0.2 和 0.1 天。对于 AgNO，半数致死浓度（LC50）随时间稳步下降，而对于 AgNM300K，在暴露的前 10 天内保持不变，然后在最后 7 天内下降了 2 倍。两种 Ag 形式的 21 天 LC50 相似，但 LC50（基于内部浓度）分别为 63 和 121 mg Ag/kg 生物干重（DW），AgNO 的毒性更高。这些结果表明，评估毒性所需的时间是毒性评估的一个重要因素，尤其是对于纳米材料。
