UNESCO Chair on Water Reuse, School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran.
Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran, 1417614411, Iran.
Environ Sci Pollut Res Int. 2019 Jan;26(3):2409-2420. doi: 10.1007/s11356-018-3787-z. Epub 2018 Nov 23.
Microalgae are key test organisms to assess the effects of chemicals on aquatic ecosystems. Zinc oxide nanoparticles (ZnO NPs) as a widely used metal oxide is considered a potential threat to these primary producers at the base of the food chain. This study investigates the toxicity of ZnO NPs, bulk ZnO, and Zn to the representative of freshwater microalgae, Raphidocelis subcapitata. To examine the effect of shape and size of nanoparticles, two types of spherical ZnO NPs with different sizes (20 and 40 nm) and two types of rod-shaped ZnO NPs with different lengths (100 and 500 nm) were synthesized. Microalgal cells were exposed to eight concentrations of each ZnO NP type from 0.01 to 0.7 mg/L for 96 h. The results showed that 0.7 mg/L of ZnO NP could completely inhibit algal growth. Size did not interfere with toxicity in spherical ZnO NPs, but the toxicity decreased by increasing the size of rod-shaped ZnO NPs. Spherical ZnO NPs acted more destructive to microalgal cells than nanorod shape. The addition of 0.7 mg/L of ZnO nanorods to samples caused 30% cell death, while 50% cell death was observed by adding the same concentration of nanospherical ZnO. Nano ZnO revealed to be more toxic than bulk ZnO and Zn. The Zn released from dissolution of ZnO NPs was one of the sources of toxicity, but the ZnO nanostructures were also an important factor in the toxicity.
微藻是评估化学品对水生生态系统影响的关键测试生物。氧化锌纳米粒子（ZnO NPs）作为一种广泛使用的金属氧化物，被认为是食物链底部这些初级生产者的潜在威胁。本研究调查了 ZnO NPs、块状 ZnO 和 Zn 对淡水微藻代表物种莱茵衣藻的毒性。为了研究纳米粒子的形状和大小的影响，合成了两种不同尺寸（20 和 40nm）的球形 ZnO NPs 和两种不同长度（100 和 500nm）的棒状 ZnO NPs。将微藻细胞暴露于每种 ZnO NP 类型的 8 个浓度范围从 0.01 至 0.7mg/L 下 96 小时。结果表明，0.7mg/L 的 ZnO NP 可完全抑制藻类生长。尺寸并不影响球形 ZnO NPs 的毒性，但棒状 ZnO NPs 的尺寸增加会降低毒性。球形 ZnO NPs 对微藻细胞的破坏作用大于纳米棒形状。添加 0.7mg/L 的 ZnO 纳米棒会导致 30%的细胞死亡，而添加相同浓度的纳米球形 ZnO 则会观察到 50%的细胞死亡。纳米 ZnO 比块状 ZnO 和 Zn 更具毒性。ZnO NPs 溶解释放的 Zn 是毒性的来源之一，但 ZnO 纳米结构也是毒性的重要因素。
