Effect of two TiO₂ nanoparticles on the growth of unicellular green algae using the OECD 201 test guideline: influence of the exposure system

ABSTRACT

This work aimed at assessing the influence of different exposure systems to perform the commonly used OECD 201 freshwater algal growth inhibition test in the context of nanoparticles hazard assessment. Two distinct TiO₂ nanoparticles were considered and three different exposure systems were investigated: Erlenmeyers flasks and 24-well microplates (both using an orbital shake system), and an alternative system using cylindrical vials and magnetic stirring. All three systems are in accordance with the OECD 201 test guideline recommendations. We concluded that the exposure systems applied to achieve the test can substantially affect the ecotoxicological results and the subsequent calculated ECx. The selected systems influenced both the interaction between algal cells and TiO₂ nanoparticles as well as the growth inhibition recorded. Disparities in ecotoxicity relative to the TiO₂ nanoparticles tested were also observed and are finally discussed.

KEY WORDS:

• OECD 201 test guideline
• exposure systems
• titanium dioxide
• Pseudokirchneriella subcapitata
• nanoparticles

Acknowledgements

This work was financially supported by the French ministry of Ecology, Sustainable Development and Energy. The authors are grateful to the European Commission Joint Research Centre who provided the TiO₂ nanoparticles.

Supplemental data for this article can be accessed at http://10.1080/02772248.2015.1124881.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

French ministry of Ecology, Sustainable Development and Energy; European Commission Joint Research Centre.