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Toxicity of single walled carbon nanotubes to rainbow trout, (Oncorhynchus mykiss): Respiratory toxicity, organ pathologies, and other physiological effects

Smith, Catherine J. and Shaw, Benjamin J. and Handy, Richard D. (2007) Toxicity of single walled carbon nanotubes to rainbow trout, (Oncorhynchus mykiss): Respiratory toxicity, organ pathologies, and other physiological effects. AQUATIC TOXICOLOGY, 82 (2). pp. 94-109.

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Official URL: http://dx.doi.org/10.1016/j.aquatox.2007.02.003

Abstract

Mammalian studies have raised concerns about the toxicity of carbon nanotubes (CNTs), but there is very limited data on ecotoxicity to aquatic life. We describe the first detailed report on the toxicity of single walled carbon nanotubes (SWCNT) to rainbow trout, using a body systems approach. Stock solutions of dispersed SWCNT were prepared using a combination of solvent (sodium dodecyl sulphate, SDS) and sonication. A semi-static test system was used to expose rainbow trout to either a freshwater control, solvent control, 0.1, 0.25 or 0.5 mg l(-1) SWCNT for up to 10 days. SWCNT exposure caused a dose-dependent rise in ventilation rate, gill pathologies (oedema, altered mucocytes, hyperplasia), and mucus secretion with SWCNT precipitation on the gill mucus. No major haematological or blood disturbances were observed in terms of red and white blood cell counts, haematocrits, whole blood haemoglobin, and plasma Na+ or K+. Tissue metal levels (Na+, K+, Ca2+, Cu, Zn and Co) were generally unaffected. However some dose-dependent changes in brain and gill Zn or Cu were observed (but not tissue Ca2+), that were also partly attributed to the solvent. SWCNT exposure caused statistically significant increases in Na+K+-ATPase activity in the gills and intestine, but not in the brain. Thiobarbituric acid reactive substances (TBARS) showed dose-dependent and statistically significant decreases especially in the gill, brain and liver during SWCNT exposure compared to controls. SWCNT exposure caused statistically significant increases in the total glutathione levels in the gills (28%) and livers (18%), compared to the solvent control. Total glutatbione in the brain and intestine remained stable in all treatments. Pathologies in the brain included possible aneurisms or swellings on the ventral surface of the cerebellum. Liver cells exposed to SWCNT showed condensed nuclear bodies (apoptotic bodies) and cells in abnormal nuclear division. Overt fatty change or wide spread lipidosis was absent in the liver. Fish ingested water containing SWCNT during exposure (presumably stress-induced drinking) which resulted in precipitated SWCNT in the gut lumen and intestinal pathology. Aggressive behaviour and fin nipping caused some mortalities at the end of the experiment, which may be associated with the gill irritation and brain injury, although the solvent may also partly contributed to aggression. Overall we conclude that SWCNTs are a respiratory toxicant in trout, the fish are able to manage oxidative stress and osmoregulatory disturbances, but other cellular pathologies raise concerns about cell cycle defects, neurotoxicity, and as yet unidentified blood home factors that possibly mediate systemic pathologies. (c) 2007 Elsevier B.V All rights reserved.

Item Type:Article
Uncontrolled Keywords:single walled carbon nanotubes; SWCNT; gill; respiration; brain pathology; liver pathology; haematology; Na+K+-ATPase; TBARS; glutathione; rainbow trout; copper; zinc
Subjects:Physical Science > Nano objects
Biomedical Science > Nanotechnology for animal health
NanoSafety > Environment, health and safety aspects of nanotechnology
Material Science > Nanostructured materials
ID Code:3060
Deposited By:Anuj Seth
Deposited On:13 Jan 2009 15:10
Last Modified:20 Jan 2009 15:31

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