A. Georgantzopoulou¹, M. Dusinska², M. Kruszewski³, Y.L. Balachandran⁴,

J.N. Audinot¹, L. Hoffmann¹ and A.C. Gutleb¹

¹Centre de Recherche Public - Gabriel Lippmann, Belvaux, Luxembourg

²Norwegian Institute for Air Research, Kjeller, Norway

³Institute of Nuclear Chemistry and Technology, Warszawa, Poland

⁴Bharathiar University, Coimbatore, India

Email: gutleb@lippmann.lu

The widespread application and use of nanoparticles (NPs) in numerous products will unavoidably lead to their release in aquatic systems. However, there is a lack of knowledge on the effects of NPs on living systems.

The present study aims to assess the effects of TiO₂ (20 nm), and Ag (20, 27 and 200 nm) NPs on Daphnia magna, the freshwater algae Desmodesmus subspicatus and validation of the use of the marine bacterium Vibrio fischeri bioluminescence as a potential pre-screening assay (mMicrotox-assay).

Characterised NPs and dispersion protocols were provided by the FP7 project NanoTEST, the Polish-Norwegian Research Fund project NorPol and by the Bharathiar University, India. Bulky TiO₂ and Ag (200 nm) and AgNO₃ were used for comparison. The organisms were exposed to increasing concentrations of NPs or AgNO₃. The inhibition of D. magna mobility, the inhibition of D. subspicatus growth and inhibition of V. fischeri bioluminescence was evaluated after 48, 72 hours and 30 minutes, respectively.

Both bulky and nano-TiO₂ caused an increase in luminescence in the mMicrotox-assay in a concentration dependent manner starting at concentrations higher than 20 and 200 mg/L for nano- and bulky TiO₂, respectively. TiO₂ NPs had no effect on D. magna mobility and D. subspicatus growth despite the high levels tested.

Size dependent effects were observed concerning Ag NPs in all organisms studied with D. magna being the most sensitive organism (Table 1). Ag 20 nm and Ag 200 nm inhibited V. fischeri bioluminescence by 12% and 15%, respectively at the highest tested concentration of 10 mg/L and therefore no IC₅₀ could be calculated.

These findings support the increasing concern on the potential harm of Ag NPs on aquatic organisms and for the environment.

Table 1. IC₅₀ for Ag NPs of different sizes as well as AgNO₃.