Toxicology of Nano Materials to Fish: A Fact Finding Pilot Study.
Lead Research Organisation:
Plymouth University
Department Name: Biological Sciences
Abstract
Nanoparticles are very small particles in the size range 1-100 nanometers. Nanoparticles have numerous applications in new materials, electrical and thermal devices, and new applications in medical instruments, biorobotics, and environmental monitoring technology. The potential benefits to mankind of nanotechnology is awesome. However, mammalian toxicity studies have revealed some concerns about adverse effects of some of these materials, such as inflammation of the airway due to inhilation of nanoparticles. The effects on wildlife are unknown, and some assessment of these effects are needed before we should allow the controlled discharge of industrial effluents, and other wastes that might contain nanoparticles, into the environment. Our proposal is a one year pilot study to look at possible effects of nanoparticles on fish. Our objectives are to measure the short and long term effects of two major types of nanoparticles to fish (i) carbon nanotubes (ii) manufactured titanium dioxide nanoparticles. Measurements will include histopathology, a range of health indices, and detailed toxicological and biochemical investigations of the fish tissues. This information is vital for environmental risk assessments, and a pre-requisite to managing potential pollution problems from new nanotechnologies.
Organisations
Publications
Chapman P
(2007)
Learned discourses Learned Discourses
in Integrated Environmental Assessment and Management
Federici G
(2007)
Toxicity of titanium dioxide nanoparticles to rainbow trout (Oncorhynchus mykiss): gill injury, oxidative stress, and other physiological effects.
in Aquatic toxicology (Amsterdam, Netherlands)
Handy R
(2007)
Absorption of solutes and toxicants onto epithelia: Fundamental principles, new chemicals, and challenges for biotic ligand models
in Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
Handy R
(2007)
Toxic effects of nanoparticles and nanomaterials: Implications for public health, risk assessment and the public perception of nanotechnology
in Health, Risk & Society
Handy RD
(2008)
The ecotoxicology and chemistry of manufactured nanoparticles.
in Ecotoxicology (London, England)
Handy RD
(2008)
The ecotoxicology of nanoparticles and nanomaterials: current status, knowledge gaps, challenges, and future needs.
in Ecotoxicology (London, England)
Handy RD
(2007)
Ecotoxicity of nanomaterials to fish: challenges for ecotoxicity testing.
in Integrated environmental assessment and management
Smith CJ
(2007)
Toxicity of single walled carbon nanotubes to rainbow trout, (Oncorhynchus mykiss): respiratory toxicity, organ pathologies, and other physiological effects.
in Aquatic toxicology (Amsterdam, Netherlands)
| Description | The overall aim of this one year pilot study was to explore the fundamental features of toxicity of two nanomaterials in rainbow trout. These were titanium dioxide nanoparticles (TiO2 NPs) and single walled carbon nanotubes (SWCNT). The research involved new methodology for conducting exposure studies with fishes and we quickly established that the agglomeration and settling behaviours of the particles changed with concentration of the nanomaterials, and would affect biological responses as well as toxicity. We therefore made some recommendations on the chemical characterisation of nanoparticles for ecotoxicity studies (Handy and Shaw, 2007) and identified the importance of including experiment-specific chemistry in each research article. The lethal concentration for TiO2 NP was above the "solubility" threshold for obtaining dispersed nanomaterials (above 10 mg l-1) suggesting low acute toxicity, but with sub-lethal effects. SWCNTs were more toxic than TiO2 NPs and mortalities were observed at doses above 1 mg l-1, with a 10% mortality threshold around 0.5 mg l-1. For this reasons, it was clear that most of the research effort needed to focus on the sub-lethal effects at low mg l-1 concentrations or less. These were also likely to be more environmentally relevant. For the sub-lethal experiments, we used a body systems approach to conduct a detailed toxicological investigation of both nanomaterials. 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 and mucus secretion. No major haematological or blood disturbances were observed in terms of red and white blood cell counts, whole blood haemoglobin, or electrolytes. Some dose-dependent changes in brain and gill zinc or copper were observed. SWCNT exposure caused statistically significant changes of enzymes in the tissues including those involved in osmoregulation and oxidative stress responses. Pathologies were observed in the brain and liver during SWCNT exposure. Stress-induced drinking also resulted in precipitated SWCNT in the gut lumen and intestinal pathology. For the titanium dioxide experiment, fish were exposed to control, 0.1, 0.5 or 1.0 mg l-1 TiO2 nanoparticles for 14 days, and similar measurements to those above were made. Exposure to titanium dioxide nanoparticles caused some gill pathologies. No major haematological or blood disturbances were observed and tissue metal levels were generally unaffected. Some dose-dependent changes in tissue zinc or copper were observed. Exposure to titanium dioxide nanoparticles also caused changes in enzyme activities in the internal organs and gills. Pathologies were noted in the liver and intestine, but with limited effects in the brain. Overall the data showed that both TiO2¬ and SWCNTs cause sub-lethal toxicity to fish, and the mechanisms include respiratory toxicity and oxidative stress. This work clearly shows that low mg l-1 doses are a concern for aquatic life, and we should therefore be concerned about the environmental risk of these concentrations, and µg l-1 levels over longer timescales. |
| Exploitation Route | One of the underlying drivers for this research was to provide data that could be used internationally in understanding the hazards and risks of nanomaterials, as well as providing methodology to conduct hazard assessments. This research has been used by the Organisation for Economic Co-operation and Development (OECD) at the working party on manufactured nanomaterials (WPMN), contributing to knowledge on hazards. Our papers (Federici et al., 2007; Smith et al., 2007) are cited in the OECD (2012) guidance on dosimetry and health effects of nanomaterials (document No: ENV/JM/MONO(2012)40) and earlier versions of the documents. Similarly, there has been national level agencies with interests in this data from the view point on environmental risk assessment (e.g., Defra in the UK, and the US EPA, CSIRO in Australia). The experimental protocols have some use in regulatory hazard assessment in commercial laboratories. The waterborne exposure studies were the first detailed reports on fish. This showed that nanomaterials in the environment had the potential to be toxic to aquatic life, albeit at low mg concentrations. This information is of value to environment agencies with responsibility for environmental risk assessment. It is also relevant to drinking water safety, since ingestion of water containing these materials caused gut pathology. The results were used by the UK Environment Agency in 2007 to identify SWCNTs as hazardous to fish life. |
| Sectors | Chemicals,Environment |
| Description | This research has already had an impact on hazard and risk assessments for nanomaterials internationally, particularly at the Organisation for Economic Co-operation and Development (OECD) at the working party on manufactured nanomaterials (WPMN). Our papers (Federici et al., 2007; Smith et al., 2007) are cited in the OECD (2012) guidance on dosimetry and health effects of nanomaterials (document No: ENV/JM/MONO(2012)40) and earlier versions of the documents. Our data is cited by the Royal Commission on Environmental Pollution in: Lawton (2008) "Novel Materials in the Environment: The case of nanotechnology," presented to Parliament, November 2008. Available at: http://www.official-documents.gov.uk/document/cm74/7468/7468.pdf It has also been used by environmental agencies in Europe, Australia and the USA. |
| First Year Of Impact | 2007 |
| Sector | Agriculture, Food and Drink,Chemicals,Environment,Healthcare,Government, Democracy and Justice,Manufacturing, including Industrial Biotechology,Other |
| Impact Types | Economic,Policy & public services |