The association between nC₆₀ and 17α-ethinylestradiol (EE2) decreases EE2 bioavailability in zebrafish and alters nanoaggregate characteristics

Abstract

Manufactured nanoparticles (NPs) released into surface waters will associate with other substances and these interactions may affect environmental fate and bioavailability of NPs and the associated substances. We investigated the association between aqueous aggregates of C₆₀ (nC₆₀) and synthetic estrogen, 17α-ethinylestradiol (EE2), and considered nC₆₀ physicochemistry and EE2 bioavailability (by measuring vitellogenin (vtg1A/B) gene expression) in zebrafish. Bioavailability of EE2 was reduced with increasing concentration of nC₆₀ (P < 0.05), and bioavailability of EE2 decreased further after aging 28 d with nC₆₀. Reduction in EE2 bioavailability was correlated with computed surface area of nC₆₀, and reduced bioavailability of EE2 upon aging was consistent with absorption of EE2 within nC₆₀ aggregates. Size and zeta potential of nC₆₀ particles were affected by EE2 (1 μg/L) and also by aging (28 d) in aqueous phase. Results indicate that nC₆₀ can reduce bioavailability of some substances and influence environmental fate and transport of associated substances.

Keywords::

• C₆₀ fullerenes
• nanoparticles
• EE2
• co-contaminant
• nanoparticle associations

Acknowledgements

The authors thank T. Heah, for laboratory assistance.

Declaration of interest: This work was funded by the U.S. EPA Science to Achieve Results (STAR) Program (grant R833333). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.