Aquatic toxicity and mode of action of CdS and ZnS nanoparticles in four microalgae species

• Published in: Environmental research Vol. 186; p. 109513
• Main Authors: Pikula, Konstantin, Mintcheva, Neli, Kulinich, Sergei A., Zakharenko, Alexander, Markina, Zhanna, Chaika, Vladimir, Orlova, Tatiana, Mezhuev, Yaroslav, Kokkinakis, Emmanouil, Tsatsakis, Aristidis, Golokhvast, Kirill
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.07.2020
• Subjects: Aquatic toxicity; CdS; Microalgae; Nanoparticles; ZnS. This work was supported by the Russian foundation for basic research (project number 19-05-50010); Nanoparticles; ZnS. This work was supported by the Russian foundation for basic research (project number 19-05-50010); Microalgae; CdS; Aquatic toxicity
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2020.109513

This study reports the differences in toxic action between cadmium sulfide (CdS) and zinc sulfide (ZnS) nanoparticles (NPs) prepared by recently developed xanthate-mediated method. The aquatic toxicity of the synthesized NPs on four marine microalgae species was explored. Growth rate, esterase activity, membrane potential, and morphological changes of microalgae cells were evaluated using flow cytometry and optical microscopy. CdS and ZnS NPs demonstrated similar level of general toxicity and growth-rate inhibition to all used microalgae species, except the red algae P. purpureum. More specifically, CdS NPs caused higher inhibition of growth rate for C. muelleri and P. purpureum, while ZnS NPs were more toxic for A. ussuriensis and H. akashiwo species. Our findings suggest that the sensitivity of different microalgae species to CdS and ZnS NPs depends on the chemical composition of NPs and their ability to interact with the components of microalgal cell-wall. The red microalga was highly resistant to ZnS NPs most likely due to the presence of phycoerythrin proteins in the outer membrane bound Zn2+ cations defending their cells from further toxic influence. The treatment with CdS NPs caused morphological changes and biochemical disorder in all tested microalgae species. The toxicity of CdS NPs is based on their higher photoactivity under visible light irradiation and lower dissociation in water, which allows them to generate more reactive oxygen species and create a higher risk of oxidative stress to aquatic organisms. The results of this study contribute to our understanding of the parameters affecting the aquatic toxicity of semiconductor NPs and provide a basis for further investigations. [Display omitted] •The aquatic toxicity of CdS and ZnS NPs was explored on four marine microalgae.•CdS and ZnS NPs show similar level of microalgae growth-rate inhibition.•Red microalgae P. purpureum are more resistant to ZnS NPs.•Phycoerythrins are possibly involved in the mechanism of algae resistance to ZnS NPs.•CdS NPs caused higher biochemical and morphological disorder in microalgae cells.