Aqueous suspension methods of carbon-based nanomaterials and biological effects on model aquatic organisms.

The preparation of aqueous suspensions of carbon-based nanomaterials (NMs) requires the use of dispersing agents to overcome their hydrophobic character. Although studies on the toxicity of NMs have focused primarily on linking the characteristics of particles to biological responses, the role of dispersing agents has been overlooked. This study assessed the biological effects of a number of commonly used dispersing agents on Pseudokirchneriella subcapitata and Ceriodaphnia dubia as model test organisms. The results show that for a given organism, NM toxicity can be mitigated by use of nontoxic surfactants, and that a multispecies approach is necessary to account for the sensitivity of different organisms. In addition to the intrinsic physicochemical properties of NMs, exposure studies should take into account the effects of used dispersing fluids.