Synergistic Effects of Nano-Sized Titanium Dioxide and Zinc on the Photosynthetic Capacity and Survival of Anabaena sp.

International Journal of Molecular Sciences

Yulin Tang¹  Shuyan Li²  Junlian Qiao²  Hongtao Wang² 

[1] State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science & Engineering, Tongji University, Shanghai 200092, China;

关键词: synergistic toxicity;    zinc;    nanoparticles;    titanium dioxide;    Anabaena sp;   

DOI  :  10.3390/ijms140714395

来源: mdpi

【 摘 要 】

Anabaena sp. was used to examine the toxicity of exposure to a nano-TiO₂ suspension, Zn²⁺ solution, and mixtures of nano-TiO₂ and Zn²⁺ suspensions. Typical chlorophyll fluorescence parameters, including effective quantum yield, photosynthetic efficiency and maximal electron transport rate, were measured by a pulse-amplitude modulated fluorometer. Nano-TiO₂ particles exhibited no significant toxicity at concentrations lower than 10.0 mg/L. The 96 h concentration for the 50% maximal effect (EC₅₀) of Zn²⁺ alone to Anabaena sp. was 0.38 ± 0.004 mg/L. The presence of nano-TiO₂ at low concentrations (<1.0 mg/L) significantly enhanced the toxicity of Zn²⁺ and consequently reduced the EC₅₀ value to 0.29 ± 0.003 mg/L. However, the toxicity of the Zn²⁺/TiO₂ system decreased with increasing nano-TiO₂ concentration because of the substantial adsorption of Zn²⁺ by nano-TiO₂. The toxicity curve of the Zn²⁺/TiO₂ system as a function of incremental nano-TiO₂ concentrations was parabolic. The toxicity significantly increased at the initial stage, reached its maximum, and then decreased with increasing nano-TiO₂ concentration. Hydrodynamic sizes, concentration of nano-TiO₂ and Zn²⁺ loaded nano-TiO₂ were the main parameters for synergistic toxicity.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland