Abstract
This study investigated the toxicity, bioaccumulation and biotransformation of copper oxide nanoparticles (nCuO) and CuSO4 in Daphnia magna. We performed acute and chronic assays, and analyzed the organisms by μ-XRF and μ-XANES. In acute assays 25 nm nCuO (LC50 0.05 ± 0.011 mg Cu per L) and CuSO4 (LC50 0.16 ± 0.015 mg Cu per L) were most toxic, while 40 nm and 80 nm nCuO had similar toxicity (LC50 2.34 ± 0.479 and 2.26 ± 0.246 mg Cu per L, respectively). In chronic assays, CuSO4 (EC50 1.7 × 10-4 ± 1.0 × 10-4 mg Cu per L) was most toxic followed by 25 nm nCuO (EC50 1.8 × 10-3 ± 8.0 × 10-4 mg Cu per L), while 40 and 80 nm nCuO were least toxic (EC50 2.10 ± 0.669 and 1.95 ± 0.568 mg Cu per L, respectively). μ-XRF showed that Cu was accumulated in the intestine and appendages of the daphnids. μ-XANES showed that 25 nm nCuO and CuSO4 were biotransformed into Cu3(PO4)2 (acute assays), whereas 40 and 80 nm nCuO remained as CuO (chronic assays). The higher toxicity exhibited by CuSO4 and 25 nm nCuO can be explained from their higher chemical reactivity (probed by catalytic decomposition of H2O2 and μ-XANES) compared to 40 and 80 nm nCuO.
Original language | English |
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Pages (from-to) | 2897-2906 |
Number of pages | 10 |
Journal | Environmental Science. Nano |
Volume | 6 |
Issue number | 9 |
Early online date | 5 Aug 2019 |
DOIs | |
Publication status | Published - 1 Sept 2019 |
Funding
The authors are grateful to the Brazilian Synchrotron Light Laboratory for beam time under proposal 20160793, Dr. C. Perez and Dr. D. Galante are kindly acknowledged for assistance during the μ-XANES measurements. We thank the Masters student R. G. Lima for carrying out the H2O2 decomposition assays. We also thank Prof. L. F. Fraceto (UNESP) for the DLS and zeta potential, and Prof. C. R. Montes (USP) for XRD measurements, respectively. This work was funded by FAPESP Young Researcher Awards 2015/05942-0 and Multiuser equipment Grant 2015-19121-8. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001.
Funders | Funder number |
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Fundação de Amparo à Pesquisa do Estado de São Paulo | 2015/05942-0, 2015-19121-8 |
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior |