Nano-TiO2 enhances the toxicity of copper in natural water to Daphnia magna

• Published in: Environmental pollution (1987) 2011-03, Vol.159 (3), p.729-734
• Main Authors: Fan, Wenhong, Cui, Minming, Liu, Hong, Wang, Chuan, Shi, Zhiwei, Tan, Cheng, Yang, Xiuping
• Format: Article
• Language: English
• Subjects: Adsorption; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Copper; Copper - pharmacokinetics; Copper - toxicity; Daphnia - drug effects; Daphnia - metabolism; Daphnia magna; Ecotoxicology, biological effects of pollution; Freshwater; Fundamental and applied biological sciences. Psychology; Inhibition; Injuries; Lethal Dose 50; Metal Nanoparticles - chemistry; Metallothionein - metabolism; Nanocomposites; Nanomaterials; Nanostructure; Titanium - chemistry; Titanium - pharmacokinetics; Toxicity; Toxicology; Water Pollutants, Chemical - pharmacokinetics; Water Pollutants, Chemical - toxicity
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2010.11.030

The acute toxicity of engineered nanoparticles (NPs) in aquatic environments at high concentrations has been well-established. This study demonstrates that, at a concentration generally considered to be safe in the environment, nano-TiO(2) remarkably enhanced the toxicity of copper to Daphnia magna by increasing the copper bioaccumulation. Specifically, at 2 mg L(-1) nano-TiO(2), the (LC(50)) of Cu(2+) concentration observed to kill half the population, decreased from 111 μg L(-1) to 42 μg L(-1). Correspondingly, the level of metallothionein decreased from 135 μg g(-1) wet weight to 99 μg g(-1) wet weight at a Cu(2+) level of 100 μg L(-1). The copper was found to be adsorbed onto the nano-TiO(2), and ingested and accumulated in the animals, thereby causing toxic injury. The nano-TiO(2) may compete for free copper ions with sulfhydryl groups, causing the inhibition of the detoxification by metallothioneins.