title: Potentiating toxicological interaction of single-walled carbon nanotubes with dissolved metals.
abstract: The present study explored the ecotoxicology of single-walled carbon nanotubes (SWCNTs) and their likely interaction with dissolved metals, with a focus on the effect of in vivo exposure in marine mussels. Any nano-scale effects were negated by the tendency of uncoated SWCNTs to agglomerate in water, particularly with high ionic strength as is the case in estuarine and full-strength seawater. However, SWCNTs, in combination with natural organic matter, remained suspended in seawater for long enough to become available to filter-feeding mussels, leading to their concentration on and increased contact with gill epithelia during exposure. For the first time, the authors describe a potentiating toxicological effect, expressed as DNA strand breaks obtained using the comet assay, on divalent metals afforded by negatively charged SWCNT agglomerates in seawater at concentrations as low as 5 µg L⁻¹. This is supported by the observation that SWCNTs alone were only toxic at concentrations ≥100 µg L⁻¹ and that the SWCNT-induced DNA damage was correlated with oxidative stress only in the absence of metals. If these laboratory experiments are confirmed in the natural environment, the present results will have implications for the understanding of the role of carbon nanotubes in environmental metal dynamics, toxicology, and consequently, regulatory requirements.
authors: Heriot-Watt University, Centre for Marine Biodiversity & Biotechnology, School of Life Sciences, Edinburgh, Scotland, UK; King Abdulaziz University, Department of Biological Sciences, Faculty of Sciences, Jeddah, Saudi Arabia.
authors: Majed
authors: M
authors: Al-Shaeri
authors: Dina
authors: D
authors: Ahmed
authors: Fiona
authors: F
authors: McCluskey
authors: Gavin
authors: G
authors: Turner
authors: Lynn
authors: L
authors: Paterson
authors: Elisabeth A
authors: EA
authors: Dyrynda
authors: Mark G J
authors: MG
authors: Hartl
mesh_terms: D000818:Animals; D020552:Comet Assay; D004249:DNA Damage; D019216:Metals, Heavy / Q000378:metabolism / Q000633:toxicity*; D049880:Mytilus edulis / Q000235:genetics / Q000378:metabolism*; D037742:Nanotubes, Carbon / Q000633:toxicity*; D018384:Oxidative Stress; D012623:Seawater; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D019216:Metals, Heavy; D037742:Nanotubes, Carbon; D014874:Water Pollutants, Chemical
keywords: Genotoxicology; Interaction; Marine ecotoxicology; Metal; Single-walled carbon nanotube