The current study focuses on the ecotoxicity of cobalt oxide nanoparticles (Co3O4 NPs) in the aquatic environment towards freshwater microalgae, Chlorella minutissima. The interaction of Co3O4 NPs with microalgae shows the growth suppressing effect. The 72 h EC 50 (effective concentration of a chemical having 50% of its impact) values of Co3O4 NPs for C. minutissima was 38.16 ± 1.99 mg/L. The decline in chlorophyll a content and increase in reactive oxygen species (ROS) also indicated the compromised physiological state of microalgae. An increased LDH (lactate dehydrogenase) level in treated samples suggests membrane disintegration by Co3O4 NPs. Light microscopy, scanning electron microscopy (SEM) and Energy Dispersive X-Ray-Scanning electron microscopy (EDX-SEM) further confirm cell entrapment and deposition of Co3O4 NPs on the cell surface. Cellular internalization of NPs, as shown by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), also contributes towards the toxicity of NPs. The findings suggest the role of extracellular as well as intracellular nanoparticles (NPs) in exerting a toxic effect on the C. minutissima.

中文翻译：

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合成的Co3O4纳米颗粒暴露于小球藻：淡水微藻中的生态毒性评估。

目前的研究集中在水生环境中氧化钴纳米颗粒（Co3O4 NPs）对淡水微藻小球藻的生态毒性。Co3O4 NPs与微藻的相互作用显示出生长抑制作用。小肠念珠菌的Co3O4 NP的72 h EC 50（有效浓度的化学药品具有50％的影响）的值为38.16±1.99 mg / L。叶绿素a含量的下降和活性氧（ROS）的增加也表明微藻的生理状态受到损害。处理过的样品中LDH（乳酸脱氢酶）水平升高表明Co3O4 NPs使膜分解。光学显微镜，扫描电子显微镜（SEM）和能量色散X射线扫描电子显微镜（EDX-SEM）进一步证实了细胞的捕获和Co3O4 NP在细胞表面的沉积。NPs的细胞内在化，如电感耦合等离子体原子发射光谱法（ICP-AES）所示，也有助于NPs的毒性。这些发现表明细胞外和细胞内纳米颗粒（NPs）在对小肠念珠菌的毒性作用中的作用。