College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China; Institute of Cancer, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
Ecotoxicol Environ Saf. 2018 Jul 30;156:75-86. doi: 10.1016/j.ecoenv.2018.03.007. Epub 2018 Mar 13.
Nanoparticles (NPs) are inevitably released into the aquatic environment for being widely used and may affect the toxicity of other contaminants already present in the environment, such as trace metals. However, the effects of NPs on the ecotoxicity of cadmium (Cd), a common environmental trace metal pollutant, are not well explored. In this study, effects of four widely used NPs TiO (n-TiO), SiO (n-SiO), Ag (n-Ag) and CdTe/CdS core/shell quantum dots (QD) on the toxicity of Cd to the freshwater algae Chlamydomonas reinhardtii were assessed respectively. Cd reduced the algae biomass, impaired the photosynthetic activities, and led to intracellular oxidative stress of algae. At non-toxic concentrations, both n-TiO (100 mg L) and n-SiO (400 mg L) attenuated the toxicity of Cd towards the algae for reducing the intracellular Cd contents, and the former was more pronounced. QD (0.5 mg L) increased the toxicity of Cd to algae, but n-Ag (0.2 mg L) had no significant influence on the Cd toxicity to algae. The microscopic observations on the ultrastructure of algae cells presented the same phenomena and n-TiO, n-SiO aggregations were clearly observed outside the cell wall. Furthermore, the regulation of NPs to the Cd toxicity towards algae was related to the intracellular nitric oxide (NO), an important signaling molecule, rather than the phototaxis of algae. Above all, this study provided a basic understanding about the difference in joint toxicity of different kinds of NPs and Cd to aquatic organisms.
纳米颗粒（NPs）由于广泛应用不可避免地会释放到水环境中，并可能影响环境中已存在的其他污染物（如痕量金属）的毒性。然而，纳米颗粒对镉（Cd）这种常见的环境痕量金属污染物的生态毒性的影响尚未得到充分探索。在这项研究中，分别评估了四种广泛使用的纳米颗粒 TiO（n-TiO）、SiO（n-SiO）、Ag（n-Ag）和 CdTe/CdS 核/壳量子点（QD）对淡水藻类莱茵衣藻毒性的影响。Cd 降低了藻类生物量，损害了光合作用，并导致藻类细胞内氧化应激。在非毒性浓度下，n-TiO（100mg/L）和 n-SiO（400mg/L）均减轻了 Cd 对藻类的毒性，降低了细胞内 Cd 含量，前者更为明显。QD（0.5mg/L）增加了 Cd 对藻类的毒性，但 n-Ag（0.2mg/L）对 Cd 对藻类的毒性没有显著影响。藻类细胞超微结构的显微镜观察呈现出相同的现象，并且可以清楚地观察到细胞壁外的 n-TiO 和 n-SiO 聚集。此外，纳米颗粒对 Cd 毒性的调节与细胞内一氧化氮（NO）有关，NO 是一种重要的信号分子，而与藻类的趋光性无关。总之，这项研究提供了对不同种类的纳米颗粒和 Cd 对水生生物联合毒性差异的基本认识。
