Factors influencing the partitioning and toxicity of nanotubes in the aquatic environment

• DOI: 10.1897/07-624.1
• Publication Date: 2008-05-12T22:45:44Z
• Authors: Alan J Kennedy,; Matthew S Hull; Jeffery A Steevens; Katerina M Dontsova; Mark A Chappell; Jonas C Gunter; Charles A Weiss,
• Keywords: Ceriodaphnia dubia; Ecotoxicity; Settling; Sedimentation; Carbon fibers

Carbon nanotubes (NTs) may be among the most useful engineered nanomaterials for structural applications but could difficult to study in ecotoxicological evaluations using existing tools relative with a lower aspect ratio. Whereas hydrophobicity and van der Waals interactions of NTs suggest aggregation sedimentation aquatic systems, consideration regarding how surface modifications influence their environmental fate toxicology is needed. Surface (e.g., functional groups coatings) are intended create conditions make dispersible aqueous suspension, as required some applications. In present study, column stability settling experiments indicated that raw, multiwalled (MWNTs) settled more rapidly than carbon black activated particles, suggesting sediment ultimate repository. The presence groups, however, slowed MWNTs (increasing order stability: hydroxyl > carboxyl raw), especially combination natural organic matter (NOM). Stabilized high concentrations NOM provided relevance water transport toxicity studies. Aqueous exposures raw decreased Ceriodaphnia dubia viability, such effects were not observed during exposure functionalized (> 80 mg/L). Sediment amphipods Leptocheirus plumulosus Hyalella azteca different sizes sediment-borne particles at concentration mortality increased particle size decreased, although induced (median lethal [LC50], 50 >264 g/kg) (LC50, 18-40 12-29 g/kg). Our findings stress it inappropriate classify all into one category terms regulation.