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The influence of humic acid on the toxicity of nano‐ZnO and Zn 2+ to the Anabaena sp.
Author(s) -
Tang Yulin,
Li Shuyan,
Lu Yao,
Li Qian,
Yu Shuili
Publication year - 2014
Publication title -
environmental toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.813
H-Index - 77
eISSN - 1522-7278
pISSN - 1520-4081
DOI - 10.1002/tox.21964
Subject(s) - nuclear chemistry , chemistry , lipid peroxidation , humic acid , photosynthesis , zinc , toxicity , quantum yield , fluorescence , biophysics , biochemistry , biology , antioxidant , organic chemistry , fertilizer , physics , quantum mechanics
This study explored the effects of humic acid (HA) on the toxicity of ZnO nanoparticles (nano‐ZnO) and Zn 2+ to Anabaena sp. Typical chlorophyll fluorescence parameters, including effective quantum yield, photosynthetic efficiency and maximal electron transport rate, were measured by a pulse‐amplitude modulated fluorometer. Results showed that nano‐ZnO and Zn 2+ could inhibit Anabaena sp. growth with the EC 50 (concentration for 50% of maximal effect) of 0.74 ± 0.01 and 0.3 ± 0.01 mg/L, respectively. In the presence of 3.0 mg/L of HA, EC 50 of nano‐ZnO increased to 1.15 ± 0.04 mg/L and EC 50 of Zn 2+ was still 0.3 ± 0.01 mg/L. Scanning electron microscopy observation revealed that HA prevented the adhesion of nano‐ZnO on the algae cells due to the increased electrostatic repulsion. The generation of intracellular reactive oxygen species and cellular lipid peroxidation were significantly limited by HA. Nano‐ZnO had more damage to the cell membrane than Zn 2+ did, which could be proven by the malondialdehyde content in Anabaena sp. cells. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 895–903, 2015.