Algal testing of titanium dioxide nanoparticles- testing considerations, inhibitory effects and modification of cadmium bioavailability

Author(s)

Nanna Bloch Hartmann, Frank von der Kammer, Thilo Hofmann, Mohammed Baalousha, Stephanie Ottofülling, Anders Baun

Abstract

The ecotoxicity of three different sizes of titanium dioxide (TiO2) particles (primary particles sizes: 10,

30, and 300 nm) to the freshwater green alga Pseudokirchneriella subcapitata was investigated in this

study. Algal growth inhibition was found for all three particle types, but the physiological mode of action

is not yet clear. It was possible to establish a concentration/dose–response relationship for the three

particle sizes. Reproducibility, however, was affected by concentration-dependent aggregation of the

nanoparticles, subsequent sedimentation, and possible attachment to vessel surfaces. It is also believed

that heteroaggregation, driven by algal exopolymeric exudates, is occurring and could influence the

concentration–response relationship. The ecotoxicity of cadmium to algae was investigated both in the

presence and absence of 2 mg/L TiO2. The presence of TiO2 in algal tests reduced the observed toxicity due

to decreased bioavailability of cadmium resulting from sorption/complexation of Cd2+ ions to the TiO2

surface. However, for the 30nmTiO2 nanoparticles, the observed growth inhibition was greater than what

could be explained by the concentration of dissolved Cd(II) species, indicating a possible carrier effect,

or combined toxic effect of TiO2 nanoparticles and cadmium. These results emphasize the importance of

systematic studies of nanoecotoxicological effects of different sizes of nanoparticles and underline the

fact that, in addition to particle toxicity, potential interactions with existing environmental contaminants

are also of crucial importance in assessing the potential environmental risks of nanoparticles.

Organisation(s)

External organisation(s)

Technical University of Denmark (DTU), Université Bordeaux

Journal

Toxicology

Volume

269

Pages

190-197

No. of pages

8

ISSN

0300-483X

DOI

https://doi.org/10.1016/j.tox.2009.08.008

Publication date

2010

Peer reviewed

Yes

Austrian Fields of Science 2012

105904 Environmental research

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