Assessment of the risks associated with nanomaterials

Assessment of the risks associated with nanomaterials for the general population, workers and the environment

As with any chemical, the fate of nanomaterials in the human body and their associated potential toxicity depend mainly on their physico-chemical properties (size, shape, solubility, etc.). However, partly due to the specific properties of manufactured nanomaterials, scientific knowledge of traditional substances cannot be directly transferred to nanoscale forms. Today, the widespread dissemination of nanomaterials through a variety of consumer products calls for a better understanding of the exposure of workers in this sector to these nanomaterials, as well as exposure of consumers and the general population as a whole. In this context, the Agency has conducted several expert appraisals on these topics.

The Agency has conducted several expert appraisals on the risks associated with nanomaterials found in the environment and in consumer products, for both occupational populations and the general public.

Review of knowledge about nanomaterials (2006)

In September 2005, the Agency was asked by the French Ministries for the Environment, Health and Labour respectively to conduct an expert appraisal of the state of knowledge about the health effects of nanoparticles and manufactured nanomaterials. This formal request led to the production of:

  • firstly, a summary of the scientific and technical knowledge about manufactured nanomaterials (their properties, fields of use, toxicology, biological and health effects, measurement tools, exposure, health impacts, regulations, standards, etc.);
  • secondly, a proposal for priority avenues for conducting studies and research on the assessment of the health risks in the workplace and for the general population.

The report resulting from this work was published in July 2006. It highlights in particular the need for a precise definition of the different types of nanomaterials, and stresses the complexity inherent in studying them because of their size, and therefore the need for a common language for comparing existing data.

Effects on the health of workers exposed to manufactured nanomaterials (2008 and 2011)

Based on these findings, the Ministries for theEnvironment, Health and Labour decided to make a new formal request tothe Agency to conduct a study on the health effects on workers exposed to manufactured nanomaterials.

To bestrespond to the questions posed by this request, the working group appointed by the Agency to produce the required expertise based its work on ananalysis of the national and international scientific literature. This analysis was supplemented by a survey of manufacturers andlaboratories involved,and byhearingswithproducers and users of nanomaterials.

According to the experts' conclusions, it is not possible to rule outthe existence of health effects on humans or impactson the environment as a result of exposure to nanomaterials.

The Agency, in agreement with all the results, conclusions and recommendations of the expert appraisal, called for the implementation of the expert group’s recommendations, especially those concerning the creation of a good practice guide for employers on the use of nanomaterials.

Given the available data on the potential hazards of nanomaterials and the existing measurement limitations, the Agency emphasised the importance of controlling human exposure to manufactured nanomaterials and applying the STOP principle that aims touse static or dynamic containment systems to establish a barrier between the operator and any potentially hazardous processes.

Numerous scientific reports regard inhalation of nanomaterials as potentially hazardous, and therefore the Agency has recommended measures to be taken to avoid or minimise worker exposure.
For the transport of nanomaterials, the Agency has recommended the application of rules used for hazardous materials.

The Agency also recommended creating a database to improve knowledge about the main uses of nanomaterials in France.  It is essential to identify personnel working in contact with nanomaterials and monitor their working conditions. This database would also aim to identify the types and quantities of nanomaterials used, the number of potentially exposed workers, and the means of prevention implemented.

Manufactured nanoparticles in water (February 2008) and in food and feed (March 2009)

To answer the questions of the Directorate General of Health, the Agency published a report on manufactured nanoparticles in water, and another on nanoparticles in food and feed. This work resulted in recommendations consistent with those from other national and international bodies.

Nanomaterials are used for a broad spectrum of applications: drugs, plant protection products, food and feed, packaging, and water treatment processes. Oral exposure to nanoparticles in the environment can also occur (via water or food). As of 2009, no water treatment process using nanoparticles had been placed on the French market and no veterinary medicinal product or plant protection product involving nanotechnologies had been submitted for authorisation in Europe.

Although the technological perspectives opened by nanotechnologies seem immense, particularly in the field of health, knowledge about the toxicity of nanomaterials is still incomplete. In addition, there is no standardised method for measuring and monitoring the fate of manufactured nanoparticles in complex matrices (the environment, food, the body, etc.).
Given these uncertainties, the Agency, as well as other international bodies, found it impossible to assess consumer exposure and the health risks associated with ingestion of nanoparticles. As a result, the Agency has urged caution with regard to the use of nanotechnologies or nanoparticles in food and feed. It also recommended that the presence of these substances in food should be subject to systematic reporting and an application for marketing authorisation.

Consumer exposure to products containing manufactured nanomaterials (2010)

The Agency received a formal request on 5 June 2008 from its supervisory ministries to:

  • develop and investigate exposure scenarios for the general population to a few manufactured nanomaterials contained in a sample of products placed on the market, taking into account the different routes of exposure;
  • assess the potential risks to the general population and the environment.

The Agency was asked to focus on the most relevant products and their uses, in order to analyse the main conditions of exposure of the general population. For this expert appraisal, only manufactured nanomaterials intentionally added to the nano-products were considered.

The study highlighted 246 consumer products available on the French market containing manufactured nanomaterials. These products (nano-products) are divided into 10 categories including cosmetics and hygiene products, textiles and building products.
Properties of nanomaterials vary in particular according to their chemical composition, size, specific surface area, surface state or shape of the nanoparticle considered. A number of commercial products were selected, each with a different and unique formulation or matrix.
With the aim of achieving a qualitative risk assessment, the working group selected four finished products containing manufactured nanomaterials in order to conduct a review of the nano-specific hazards and develop exposure scenarios. The products studied were: antibacterial socks containing silver nanoparticles, cement containing titanium dioxide nanoparticles, sunscreen lotion containing titanium dioxide nanoparticles and a food ingredient containing silica. The Agency tested the conventional risk assessment methodologies on these four products.
Although scientific studies regularly suggest the possibility of risks to health and the environment of certain nanomaterials, for the four products studied, the lack of data (physico-chemical characterisation, toxicity, etc.) meant that it was impossible to estimate the risk, which cannot therefore be ruled out.

Faced with this uncertainty, the Agency recommended:

  • promoting research in the fields of physico-chemical characterisation, exposure assessment, toxicology and ecotoxicology;
  • implementing traceability of data and providing information for consumers on products containing manufactured nanoparticles (nano-products);
  • limiting the exposure of consumers and the environment (in addition to that of workers) through a phased approach, in particular by promoting safe products, not containing nanomaterials, that are equivalent in terms of function, efficiency and cost.

These recommendations apply to both nano-products already on the market and future nano-products.

These studies reveal the urgent need to advance knowledge about exposure and the potential hazards of nanomaterials. Only a very small percentage of the published studies on nanomaterials currently relate to the risks to health and the environment.
The first effort should focus on the standardisation of methods for characterising nanomaterials, but the research priorities should also target toxicology, ecotoxicology and exposure measurement.

Following this work, the Agency issued an internal request to develop a pragmatic risk assessment methodology adapted to nanomaterials. To do this, it set up a special working group reporting to its Expert Committee (CES) on physical agents.

Assessment of risks associated with nanomaterials - issues and update of current knowledge (May 2014)

This summary of knowledge shows that despite the advances in scientific knowledge, major uncertainties remain about the effects of nanomaterials on health and the environment. It identifies a wide variety of hazard characteristics and notes the great complexity involved in understanding exposure situations for humans and the environment, thus making it difficult to conduct specific risk assessments. Given the time such assessments would take, the Agency recommends implementing, without delay, tools to improve risk management through a stronger regulatory framework at European level.

Effects of certain nanomaterials on living organisms

Drawing on a review of all available data and scientific publications around the world, the report documents the effects identified on living organisms. Based onin vitroandin vivoanimal tests, it first demonstrates the ability of nanomaterials to cross physiological barriers, and highlights the toxicity of certain nanomaterials, noting that there are currently no data directly concerning humans, due to the lack of epidemiological studies.

Given these factors and faced with the complexity of the subject, the Agency has made several recommendations with a view to stimulating research: to reduce the numerous scientific uncertainties in our knowledge, and to developing regulations and standards that provide better protection for humans and the environment.

ANSES’s recommendations

Regarding research, the Agency recommends implementing multidisciplinary projects to develop knowledge of the characteristics and hazards of nanomaterials, throughout the product life cycle. This mainly involves promoting the development of appropriate safety tests for assessing the health risks of products containing nanomaterials intended to be placed on the market.

In addition, ANSES is calling immediately for a strengthened regulatory framework for manufactured nanomaterials at the European level, in order to better characterise each substance and its uses, taking into account the entire product life cycle.

ANSES believes that the array of available scientific data on the toxicity of certain nanomaterials is sufficient to consider regulating them according to the European CLP (classification, labelling and packaging of substances and mixtures) and REACh (chemicals) Regulations. In this context, ANSES recently published recommendations on adapting the REACh Regulation to take into account the specific characteristics of nanomaterials.

This regulatory framework would enhance the traceability of nanomaterials intended to be used in consumer products, from production through to distribution, mainly with a view to improving characterisation of population exposure, and better targeting the risk assessments to be conducted. These risk assessments could lead to restrictions on their use or even to their prohibition, in the framework of the REACh Regulation.

Photo Credit : Jean-François Hochepied, Mines-ParisTech