Nanoparticles, human health hazard and regulation

Our plain-English summary of Nanoparticles, human health hazard and regulation, by A. Seaton, L. Tran, R. Aitken, et al (Journal of the Royal Society, Interface, 2010).

The study

• Authors: A. Seaton, L. Tran, R. Aitken, K. Donaldson
• Journal: Journal of the Royal Society, Interface
• Published: 2010;7 Suppl 1(Suppl 1):S119-29
• Cited by: 139 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

New developments in technology usually entail some hazard as well as advantage to a society. Hazard of a material translates into risk by exposure of humans and/or their environment to the agent in question, and risk is reduced by control of exposure, usually guided by regulation based on understanding of the mechanisms of harm. We illustrate risks relating to the causation of diseases associated with exposure to aerosols of combustion particles and asbestos, leading to paradigms of particle toxicity, and discuss analogies with potential exposure to manufactured nanoparticles (NPs). We review the current understanding of the hazard of NPs derived from the new science of nanotoxicology and the limited research to date into human exposure to these particles. We identify gaps in knowledge relating to the properties of NPs that might determine toxicity and in understanding the most appropriate ways both to measure this in the laboratory and to assess it in the workplace. Nevertheless, we point out that physical principles governing the behaviour of such particles allow determination of practical methods of protecting those potentially exposed. Finally, we discuss the early steps towards regulation and the difficulties facing regulators in controlling potentially harmful exposures in the absence of sufficient scientific evidence.

In plain English

This article is a review, not a new study. The authors drew on past research on combustion particles in air pollution and on asbestos to discuss possible health hazards of manufactured nanoparticles, the limited research on human exposure to them, and early steps toward regulation. They described what is called the fibre paradigm: research has linked the harm caused by asbestos mainly to four factors. These are fibres long enough that lung scavenger cells cannot remove them, fibres thin enough to be breathed deep into the lung, resistance to dissolving in the lung, and a sufficient dose. They wrote that dose, insolubility and fibre dimensions explain the epidemic of mesothelioma. They cited one study, by Han and colleagues, that reported carbon nanotube concentrations of 194 and 173 fibres per millilitre during blending and mixing. All of those fibres were too short to count as fibres under World Health Organization criteria. The authors concluded that carbon nanotubes likely to release single long fibres into the air should be treated as asbestos. They also concluded that reducing or preventing exposure should be the aim of regulating any nanoparticle considered likely to be toxic.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Narrative review
• Who was studied: No study population. The authors reviewed published research on the hazards of nanoparticles (nanotoxicology), on combustion particles and asbestos, and the limited research on human exposure to nanoparticles.
• Exposure: Combustion particles in air pollution (including diesel exhaust), asbestos fibres, and manufactured nanoparticles including carbon nanotubes. The fibre paradigm derived from asbestos research was discussed as applying to any inhaled fibre.
• Main results:
  • The authors wrote that research has related the lung-scarring and cancer-causing effects of asbestos primarily to four factors: fibre length, fibre diameter, insolubility or resistance to dissolution in the lung, and a sufficient dose to the target organ.
  • The authors stated that dose, insolubility and fibre dimensions explain the epidemic of mesothelioma among workers who inhaled asbestos.
  • Citing one workplace study (Han et al. 2008), the authors reported carbon nanotube concentrations of 194 and 173 fibres per millilitre during blending and mixing. All fibres were too short to be considered fibres under World Health Organization criteria: the maximum length was 1500 nm, against the WHO minimum of 5000 nm. Enclosing the blending activity reduced the fibre count by four orders of magnitude.
  • In the workplace studies reviewed, engineering control systems were in general broadly effective. Exposure occurred where systems were not used properly, were defective or had been deliberately disabled.
  • The authors proposed that carbon nanotubes likely to release single long fibres into the air should be treated as asbestos, and that exposure should be controlled by counting fibres using asbestos methods with electron microscopy.
• The authors' conclusion: The authors concluded that a fundamental way of avoiding harm is reducing or completely preventing exposure, and that this should be the aim of regulation of any nanoparticle considered likely to be toxic.
• Limitations the authors state:
  • The authors stated that a quantitative risk assessment of nanoparticles is not yet possible.
  • The authors noted that few studies have assessed human exposure to nanoparticles at work.
  • The authors stated that the risk assessment approach they outlined is likely to give no-effect levels too low to tell apart from background levels of airborne particles.

Topics

Medical terms in this study, explained in our Lexicon: Causation.

Related studies

• Nanoparticles and potential human health implications: past and future directions. Preface — M. Gulumian, V. Vallyathan (2010)
• Identifying the pulmonary hazard of high aspect ratio nanoparticles to enable their safety-by-design — K. Donaldson, F. Murphy, et al. (2011)
• Nanosensors and particles: a technology frontier with pitfalls — V. Vogel (2019)
• An in vitro testing strategy towards mimicking the inhalation of high aspect ratio nanoparticles — C. Endes, O. Schmid, et al. (2014)
• Predicting EMP hazard: Lessons from studies with inhaled fibrous and non-fibrous nano- and micro-particles — G. Oberdörster, U. Graham (2018)
• Necessity and approach to integrated nanomaterial legislation and governance — J. Wang, J.D. Gerlach, et al. (2013)

Browse return to medical research.