Even if nanoparticles were conclusively shown to be safe for human health, which is highly unlikely, a free market would permit consumers to decide whether or not to buy products that contain them. This does not happen in Australia.
Nanotechnology, the science of the very small, is well known for the hype associated with its fast introduction into many unexpected corners of our lives. To some observers it is also notorious for a nearly complete lack of regulation, labelling and pre-market safety testing. One widely used nanoparticle is titanium dioxide.
In its traditional form, this chemical has a low toxicity, and is used in a range of consumer products. Increasingly, it is being employed at the nano scale, and according to some scientists this presents definite, but unquantifiable, risks.
Best publicised is its use in many sunscreen products, along with nano-scale zinc oxide. In nano form, its major advantage is that it scatters less visible light. Unlike in the EU and New Zealand, where nano sunscreens are required to be labelled, in Australia the Therapeutic Goods Administration (TGA) does not require this. Instead, the TGA is concerned that ‘nano-free’ claims might imply that nano products are unsafe, and prohibits the use of this statement on both packaging and company websites.
Until recently, Friends of the Earth (FoE) Australia maintained a Safe Sunscreen Guide that detailed those brands believed to be nanoparticle-free. This was discontinued after testing found that several brands previously listed in the nano-free category had made misleading claims, perhaps unintentionally. There now appear to be one or two organic brands that are nano free.
Nano titanium dioxide’s highly reactive qualities have resulted in some unanticipated problems. On some BlueScope Steel Colorbond roof sheets, the paint was found in a 2008 study to be wearing through up to a hundred times faster where there were sunscreen finger marks and shoe impressions. As the most chemically reactive nanoparticle used in sunscreens, the finger pointed to nano titanium dioxide being the primary cause. Similar problems have been observed on car paintwork.
According to the mainstream view, human safety concerns are negligible because nano titanium dioxide is unable to cross the skin barrier. However, sometimes the skin is broken, and there is also a risk that this form of titanium dioxide could react with the skin layer itself when exposed to sunlight and water, resulting in DNA damage and possible skin cancer. These concerns are shared by dermatologists such as Robert Salmon in Wollongong. FoE in both Australia and the US have called for a sunscreen ban on the riskier ‘anatase’ form of nano titanium dioxide.
Due to its size, once inside the body nano titanium dioxide is capable of crossing the placenta and reaching the foetus, and also crossing the blood-brain barrier. A 2009 American study has revealed that its ingestion causes double-strand DNA damage and inflammation in mice. These results are supported by a 2011 Swiss-French study that concludes that its inflammatory action in the lungs is similar to that of asbestos. If this is correct, the full extent of the health damage may only emerge after a long time lag.
Given all of these findings, it is concerning that nano titanium dioxide is now being used in a range of products, including:
- Spray-on sunscreens, where inhalation is a potential risk.
- As a white food colouring (E171), found in some products such as sweets, chewing gum, and a range of processed foods. A 2012 scientific study measured 36 per cent of the titanium dioxide in a wide range of American food products as being less than 100 nanometers in at least one dimension. At present no ‘nanofood’ labelling is required anywhere in the world.
- Edible coatings on some fruits and vegetables for improved shelf life. Testing by FoE USA in 2013 identified nano titanium dioxide on apples, pears, capsicums and cucumbers that had been grown in Latin America to be sold in North America. Other tests have shown that these residues cannot be washed off.
- As an ingredient in some nutritional supplements.
- As an ingredient in some pharmaceuticals.
- In a wide range of personal care products, including soap, toothpaste, cosmetics, mouthwash, deodorant, and shaving cream. Since 2013, EU cosmetics rules have required nanoparticles to be labelled.
- For spraying interior and exterior walls as a ‘photocatalyst’ for removing pollutants, deodorising and disinfecting.
Other uses include coating glass (for ease of cleaning), coating mirrors (to prevent fogging), coating tiles (as a disinfectant), and in plastics.
Inevitably, the risks will be magnified for workers who are required to use this form of titanium dioxide on the job. Authorities in the US and Canada have already dubbed it as a ‘potential occupational carcinogen’.
Also unknown is the effects of these particles as they enter the environment, ending up in waterways, sewerage systems and landfills. Nano titanium dioxide is already being used experimentally for waste water treatment.
Even if nanoparticles were conclusively shown to be safe for human health, which is highly unlikely, a free market would permit consumers to decide whether or not to buy products that contain them.For those who follow the precautionary principle, it is well worth lobbying the Federal Government, calling for labelling.
In the meantime, concerned consumers can deal directly with industry, passing on our concerns, and asking for written responses about whether nanoparticles are being employed in more risky end uses. Rather disturbingly, media enquiries made overseas to several large food companies showed that, like consumers, they were in the dark about nano-ingredients, and were obliged to research their supply chains. The simplest solution for screening out nanofoods is to buy certified organic.
It is hard to reconcile the sharp disparity between the warnings found in peer-reviewed journals, and a blinkered enthusiasm for spreading these particles everywhere before checking that they are safe.
Friends of the Earth Emerging Tech Project http://emergingtech.foe.org.au
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