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Nanomaterials – should we be concerned?

By Sandra Madray

There is clearly a need for regulations or amended regulations that are specific to nanomaterials, with mandatory information disclosure (not merely voluntary measures) that would assist in filling the information gaps that government and non-governmental scientists alike need, to assess nanomaterials accurately.

Nanomaterials are extremely tiny – less than 100 nanometres in size and approximately 100,000 times smaller than the diameter of a strand of hair. Canada has no single regulatory definition for nanomaterials. Existing regulatory frameworks are currently being used for nanomaterials as there are no specific regulations to deal with them. Nor is there any legal requirement to disclose the presence of a nanomaterial in a consumer product. To date, we have an incomplete understanding of the fate of nanomaterials after they enter the body through inhalation, ingestion, and dermal exposure, though there is some evidence of harm from fibrous nanomaterials made of carbon, which induce inflammation in the lungs in ways that are similar to asbestos. We also lack an understanding of the fate of these materials in the environment. Yet, despite this lack of evidence, we are exposed to nanomaterials on a daily basis through the products we use or possibly through the handling and use of materials in the workplace.

What is a nanomaterial?

We often hear about nano-silver and nano-titanium dioxide in consumer products, but we probably do not stop to think why these chemicals are referred to as nanomaterials, nor why they are being used. We also probably never stop to think about the impact of these materials on human health and the environment.

In Canada and the U.S., there is no single regulatory definition for nanomaterials. Health Canada considers any manufactured substance or product and any component material, ingredient, device, or structure to be a nanomaterial if:

  1. It is at or within the nanoscale (1-100 nanometers) in at least one external dimension, or has internal or surface structure at the nanoscale, or;
  2. It is smaller or larger than the nanoscale in all dimensions and exhibits one or more nanoscale properties/phenomena.

A nanometer (nm) is one millionth of a millimeter, approximately 100,000 times smaller than the diameter of a human hair. These tiny particles exhibit unique properties that are very different from those of larger particles of the same material.

Nanomaterials can be naturally occurring (DNA, blood-borne proteins, some viruses, volcano ash); they can also be created or engineered.
Nanoparticles/nanomaterials come in many shapes. These include spheres (fullerenes or buckeyballs), tubes (single or multi-walled), and nanoshells.

Why engineered nanomaterials?

Engineered nanomaterials can be made from existing substances such as carbon, silicon, silver, gold, zinc and metal oxides of titanium, iron and zinc. Their small size results in a high surface area, with greater chemical and biological reactivity. Nanomaterials often exhibit new and specific properties, not seen with the common bulk chemicals that have larger particle sizes, including optical, catalytic, electric and electromagnetic properties. When added to some existing materials, nanomaterials can change mechanical and structural surface properties, resulting in lighter, more stable materials. Nanomaterials may also be anti-bacterial, and are used for unique pharmacokinetic and drug targeting within the body. (1,2)

The following are some examples of nanomaterials that exhibit properties that are not the same as bulk versions of the same materials in their naturally occurring form:

  1. Nano-gold: Bulk gold metal is chemically fairly inert, but nanoscale gold can act as a chemical catalyst. In the nanosize range, it exhibits different colours according to particle size.
  2. Nano-silver: Nano-silver has shown more efficient anti-microbial activity than bulk silver, as more silver ions are released rapidly because of the greater surface area. The silver ions are anti-microbial.
  3. Nano-particles in food: Nutritional additives can be added in the form of nanoparticles. These are nano-encapsulated bioactive ingredients such as Omega-3 fatty acids, coenzyme Q10, vitamins, preservatives, food colourings, flavonoids, and essential oils. They are expected to have greater bioavailability, improved solubility and increased potency compared to the non-nano versions of the same materials, so that smaller quantities of additives will have to be used.

Nanomaterials are used in many industrial, consumer and medical applications. Some that can pose high exposure potential (3,4,5,6) include:

  1. Nutritional additives;
  2. Sunscreens, cosmetics and personal care products (e.g. titanium dioxide, oxides of zinc, iron, aluminum and silicon, carbon fullerenes);
  3. Anti-bacterial properties in many consumer products including clothes (e.g. silver);
  4. Stain-resistant clothing and other articles (furniture);
  5. Food packaging with food contact (e.g. silver, zinc oxide);
  6. Agrichemicals and pesticides;
  7. Pharmaceuticals that can target specific organs or cells in the body (e.g. cancer cells) with the intent of improving effectivness;
  8. Addition to some materials for strength and lighter weight (e.g. fabrics, dental sealants, sporting equipment); and
  9. Environmental remediation.

Some applications of nanotechnology present lower potential for everyday exposure, but occupational exposures may be significant:

  1. Aviation industry;
  2. Construction materials;
  3. Tires; and
  4. Electronics, including solar energy equipment.

Nanotechnology is considered revolutionary and this has resulted in considerable interest by business, academia, and government. Nanomaterials have found their way into our lives, largely without our knowledge.

Small size and unique properties – should there be concerns?

While there is great excitement about the novel properties and uses of nanomaterials, there is a lack of data on the potential effects on human health and the environment. We should be concerned that we may have a ‘run away’ technology where the appropriate risk assessment and risk management of these new materials lag far behind their commercialization.

There is also concern that the 100 nm definition for nanomaterials may not capture all potential harms to health and the environment; larger particles sometimes exhibit similar properties.

Most countries have few requirements for nanomaterials pertaining to occupational health and safety, public health and the impact on the environment. Indeed, even the disclosure and labeling of nanomaterials in consumer products is lacking.

A) HEALTH

The shape, size, high surface area and reactivity – their unique properties – are also key to their biological effects, Currently, the assumption is that until proven otherwise, differences resulting from particle size and shape are not physiologically important.

The scientific characterization of nanomaterials is in the early stages of development, and epidemiologists are still uncertain about the how best to measure exposures. Scientists are still pondering where to start with large population studies so that exposure and risks can be better defined and understood.

At present, there is an incomplete understanding of the fate of nanomaterials after they enter the body through inhalation, ingestion, and dermal exposure. In the occupational setting, inhalation is probably the predominant route of exposure. Research studies of occupational exposures are still in their infancy, with inadequate information about the effects of various types of nanomaterials, once in the lungs.

Fibrous nanomaterials made of carbon have been shown to induce inflammation in the lungs in ways that are similar to asbestos. Do we want a repeat catastrophe as with asbestos? Clearly, the answer is no!

We are also exposed to nanomaterials through our daily use of personal care products; however, product labeling does not indicate the presence of these materials. Some labels may indicate the presence of a nanomaterial by using words like nanospheres, nanosomes, nanoencapsulated, nanodelivery system, micronized. Since the safety of these products has not been validated or substantiated, there is no warning sign to indicate their potential risks

Limited evidence is none-the-less concerning. Nano-silver used as an anti-microbial ingredient in consumer products has shown evidence of toxicity in the brain and liver cells of rats, and in germ-line stem cells of mice. Some of the evidence for toxicity of nano titanium dioxide (rutile and anatase), which is used as a UV protector as well as a food additive, indicate DNA damage to human skin cells when exposed to UV light – precisely the conditions of use!

Some nanomaterials are capable of crossing the blood brain barrier, with the potential for negative health outcomes. However, the flip side of this is the possible application of nanomaterials and nanodevices for neural regeneration, neuroprotection, and targeted delivery of drugs across the brain blood barrier. In an attempt to balance both sides of this equation, further studies are essential both for the intentional and unintentional crossing of the human blood brain barrier.

Even – or perhaps – especially with the limited data indicating that nanomaterials can significantly harm human health and the rapidly increasing use of nanotechnology in our everyday lives, governments are obliged to be more proactive and to require safety data from industry before nano-based products are marketed. The current limited data in no way supports a conclusion of “substantial equivalence” to non-nano counterparts, or “no harm.” From a public health perspective, concerns about the impact of nanomaterials include cancer and other chronic diseases.

B) REGULATORY REGIMES

Internationally, the use of nanomaterials in consumer and industrial products has burgeoned; however, it is not clear how many and which products on the market actually contain nanomaterials. Concerns such as lifecycle and risks associated with exposure to these materials – whether in raw form or in products – all highlight the need for a regulatory framework to address these materials.

Voluntary measures to obtain information about health and safety from nano-related industries would likely result in a lack of information, as there is no obligation to participate, nor to disclose negative information about a substance. Voluntary compliance has not often been successful.

In Europe, there has been much discussion related to a mandatory public registry for nano-containing products. Whether there is a public registry for the European Union (EU) or several for individual member countries, this is an efficient way to know what products on the market contain nanomaterials. A mandatory registry would also identify use patterns, which would help to determine human exposure and the environmental fate of these substances.

Setting up a harmonized registry in the European Union (EU) is a difficult task as there are different national approaches, though there are some existing tools (regulations) for mandatory nanotechnology governance. Generally, member countries indicate that all nanomaterials should be evaluated, and that there should be public inventories and labeling to bring more transparency to the system.

In the United States, the National Institute of Environmental Health Sciences (NIEHS) has indicated its commitment to support the development of nanotechnologies that can be used to improve products and solve global problems in areas such as energy, water, medicine and environmental remediation. The NIEHS also intends to investigate the potential risks that nanomaterials pose to human health and the environment. The U.S. also has some tools for mandatory nanotechnology governance though as in the EU, there needs to be a more focused approach.

The Canadian scene

Canada has been actively involved in international and domestic work on industrial nanomaterials

While there is no single regulatory definition for nanomaterials, there is a working definition that requires a single dimension of the nanomaterial to be at or between the nanoscale of (1 – 100 nm).

In the absence of a specific regulatory framework for nanomaterials, existing regulatory frameworks are currently being used. These materials are covered under the Canadian Environmental Protection Act 1999 (CEPA 1999). And, there are other legislative frameworks for nanomaterials not covered under CEPA 1999; for example, pesticides will be controlled under the Pest Control Products Act, consumer products by the Canada Consumer Products Safety Act, and the Food and Drugs Act will apply to all food, drugs, cosmetics and medical devices.

Environment Canada and Health Canada will continue to establish research priorities and fund projects to improve the science that is used to evaluate the safety of nanomaterials.7 They are currently supporting a project aimed at quantifying the releases of nanomaterials from various industrial matrices such as rubber and paints.(7)

At the Experimental Lakes Area (ELA) in northwestern Ontario, research is underway to determine the effects of nano-silver in the aquatic environment. However, nano-silver is already in consumer, medical and industrial products, and is flushed down the drain daily from homes, hospitals and businesses.

There has been limited multi-stakeholder engagement with the government regarding nanotechnology and public discussions have not occurred. As the government continues its work on nanotechnology, we hope there will be some incentive for vested interests to share information with interested stakeholders, and that there will be a more public platform for engagement and transparency.

On the international front, Canada is working with other countries to develop scientific and research capacities under the Organization for Economic Co-operation and Development (OECD), terminology and nomenclature under the International Organization for Standardization (ISO), and common regulatory approaches under the Regulatory Co-operation Council Nanotechnology Workplan (RCC).7 The RCC is between Canada and the U.S., and attempts are being made to harmonize the approach on nanotechnology where there are common elements between both parties. By the end of 2013, the RCC Nanotechnology group will be finalizing its report.

Conclusion and Actions

Nanotechnolgy and its applications are moving ahead at a rapid pace, and presently many consumer and industrial products contain nanomaterials. Effective regulations to govern nanomaterials are lacking, and currently in Canada, nanomaterials are being assessed and regulated using existing legislation. This is challenging in the absence of data needed for assessment.

Lack of engagement and information disclosure by the nano-associated industries will eventually impact public perception of this sector. New regulations specific to nanomaterials with mandatory information disclosure (not merely voluntary measures) would assist in filling the information gaps that government and non-governmental scientists alike need to assess nanomaterials accurately. Amendments to existing regulations would also help.

Information on the impacts of nanomaterials on human health and on the environment as the public and workers are exposed to nanomaterials is sadly lacking. We do not know if the government will take action to identify existing nanomaterials already in commercial use. Until the many information gaps are filled, the government should adopt a more precautionary approach with respect to the approval and continued use of nanomaterials.

Occupational exposure to nanomaterials is an issue. Unions, federal and provincial governments, as well as interested stakeholders, must collectively address worker exposure to nanomaterials. It is critical to include a clause in the Canadian Labour Code regarding exposure to nanomaterials, is critical. The lack of data on the effects of occupational exposure to nanomaterials should not be parlayed into a perception of “no harm.”

Although there is no product labeling that specifically identifies the presence of a nanomaterial in a consumer product, there can be some indications of its presence in a product. For example, anti-bacterial cleaning cloths with silver could contain nano-silver. Think again before buying those products. Is nano-silver safe for general consumer use, and are safer alternatives available?

In our day-to-day lives, we can check out our personal care products for the presence of nanomaterials using the Environmental Working Group’s Skin Deep Cosmetics Database – Nano-materials: prevalence in personal care products. If the products you and your family use contain nanomaterials, question the manufacturer about the labeling, and ask about the safety of the product and whether there are similar products without nanomaterials. You can choose to use safer products once given sufficient background information.

Equally important, there has been very little public pressure on the government to be more transparent in its regulatory approach to nanotechnology and nanomaterials. Individuals and organizations can ask Environment Canada and Health Canada for updates on impending regulations for nanomaterials, and request that the government implement a call for information (voluntary or mandatory) from industry on nanomaterials use and safety. Contact your Member of Parliament for help in getting a response from Health Canada and/or Environment Canada.

Sandra Madray is a Board Member of Prevent Cancer Now.

References:

  1. Health Canada: Policy Statement describing Health Canada’s Working Definition of Nanomaterials. Effective date October 6, 2011.
    http://www.rivm.nl/bibliotheek/rapporten/340370001.pdf (accessed May 17, 2013)
  2. Wijnhoven, et al. 2009. National Institute for Public Health and the Environment. Denmark. RIVM Letter Report 340370001/2009.
    http://www.rivm.nl/bibliotheek/rapporten/340370001.pdf (accessed May 19, 2013)
  3. Friends of the Earth (FOE). Out of the Laboratory and on to our Plates: Nanotechnology in Food & Agriculture. 2nd edition 2008. Pages 10-19.
    http://nano.foe.org.au/sites/default/files/Nanotechnology%20in%20food%20and%20agriculture%20-%20web%20resolution.pdf (accessed May 17, 2013)
  4. Sahasrabudhe, N. Nano Materials. State of California, Department of Toxic Substances Control (DTSC), U.S.A. as presented through the Western Sustainability and Pollution Prevention Network (WSPPN) Webinar May 2, 2013.
    http://wsppn.org/wp-content/uploads/2011/09/Nano-Materials_Neena-.pdf (accessed May 17, 2013)
  5. National Institute of Health Sciences, U.S. Department of Health and Human Services, U.S. Federal Government.
    http://www.niehs.nih.gov/health/topics/agents/sya-nano/ (accessed May 18, 2013)
  6. Wijnhoven, et al. 2009. National Institute for Public Health and the Environment. Denmark. RIVM Letter Report 340370001/2009.
    http://www.rivm.nl/bibliotheek/rapporten/340370001.pdf (accessed May 19, 2013)
  7. Canadian Federal Government: Chemicals Management Plan Stakeholder Advisory Council Meeting, Ottawa May 16, 2013. Presentation: Industrial Nanomaterials in the Domestic and International Context.

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Also in the JULY 2013 Issue of An Ounce

Published: July 1st, 2013