Nano-TiO2 enhances the toxicity of copper in natural water to Daphnia magna |
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Authors: | Fan Wenhong Cui Minming Liu Hong Wang Chuan Shi Zhiwei Tan Cheng Yang Xiuping |
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Affiliation: | a Department of Environmental Science and Engineering, School of Chemistry and Environment, Beihang University, Beijing 100191, China b Research Center for Green Chemistry and Engineering, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275, China |
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Abstract: | 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-TiO2 remarkably enhanced the toxicity of copper to Daphnia magna by increasing the copper bioaccumulation. Specifically, at 2 mg L−1 nano-TiO2, the (LC50) of Cu2+ 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 Cu2+ level of 100 μg L−1. The copper was found to be adsorbed onto the nano-TiO2, and ingested and accumulated in the animals, thereby causing toxic injury. The nano-TiO2 may compete for free copper ions with sulfhydryl groups, causing the inhibition of the detoxification by metallothioneins. |
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Keywords: | Nano-TiO2 Toxicity Copper Daphnia magna Metallothionein |
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