Abstract
Titanium dioxide (TiO2) nanoparticles possess the potential to coexist with Copper (Cu2+) in soil. The individual and combined toxicity of these two chemicals was evaluated using the bacterium Bacillus subtilis, a known soil model bacterium. Cu2+ (6.25–50 µg mL−1) alone produced toxicity to bacteria as evidenced by the decreased cell viability and deceased α-amylase production. The addition of TiO2 (50 mg mL−1) enhanced the Cu2+-induced decrease in cell viability but elevated amylase activity. TiO2 did not markedly affect the growth rate and lag period. A primary cause of TiO2 increasing Cu2+ toxicity is presumed to be associated with hydroxyl radical formation, while increased amylase activity is considered to arise from Cu2+ facilitating TiO2 degradation ability.
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Acknowledgments
Funding for this research was provided by the project grants of National Natural Science Foundation of China (nos 40871223 and 40901148), and Science and Technology Commission of Shanghai Municipality, China (no. 0752nm025).