Nano-TiO2 modifies heavy metal bioaccumulation in Daphnia magna: A model study

• Published in: Chemosphere (Oxford) 2023-01, Vol.312, p.137263, Article 137263
• Main Authors: Wang, Ying, Gao, Xiang, Cheng, Yinghao, Peijnenburg, Willie J.G.M., Dong, Zhaomin, Fan, Wenhong
• Format: Article
• Language: English
• Subjects: Bioaccumulation; Daphnia magna; Metals; Nano titanium dioxide (nano-TiO2); QSAR model
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2022.137263

Due to special properties, nano-TiO2 will interact with heavy metals and other pollutants in water, thus affecting the environmental behavior and ecotoxicity of these pollutants. However, the exact manner in which nano-TiO2 affects the bioaccumulation mechanisms of heavy metals is still unclear now. In the present study, quantitative structure bioaccumulation relationship (QSBAR) models were established to explore the relationships between physicochemical parameters of heavy metals and their accumulation in Daphnia magna in the absence and presence of nano-TiO2 at low metal exposure concentrations. The results showed that different physicochemical parameters affected the bioaccumulation of metals in Daphnia magna. The metal accumulation could be described by means of a Comprehensive Parameter composed of seven parameters, i.e., atomic number (AN), relative atomic weight (AW), atomic radius (AR), atomic ionization potential (AN/ΔIP), covalent index (X2r), second ionization energy (I2) and electrochemical potential (E0), in the absence of nano-TiO2, whereas the metal accumulation increased with the increase in Van Der Waals radius (rw) of metals in the presence of nano-TiO2. It was demonstrated that the bioaccumulation mechanism of the metals to Daphnia magna changed in the presence of nano-TiO2. Moreover, the bioaccumulation of more than 85% of the metals increased in the presence of nano-TiO2, but it increased differently for different metals. The present study provides an alternative approach to understand the mechanism of heavy metal bioaccumulation at low metal exposure concentrations and the effect of nano-TiO2 on metal bioaccumulation. [Display omitted] •QSBAR models for predicting metal accumulation in D. magna were developed significantly.•The accumulation of different metals in the absence and presence of nano-TiO2 differ.•Metal accumulation increases with nano-TiO2 even at a low metal exposure concentration. Capsule Abstract: The findings demonstrate that the presence of nano-TiO2 impacts the bioaccumulation mechanism of metals to Daphnia magna and this will be helpful to more accurately assess the environmental risk of the coexistence of nanomaterials and contaminants in aquatic environments.