First Large Study on Nanomaterials In Household and Commercial Products Concludes They Cause Lung Inflammation and Damage
A large consortium of scientists from across the country have found that breathing ultrafine Titanium dioxide (TiO2) nanoparticles, found in everything from cosmetics to sunscreen and paint to vitamins, can cause lung inflammation and damage. A vast and rapidly expanding array of engineered nano-products are flooding the consumer market unregulated as evidence of toxicities accumulate.
The research on two of the most common types of engineered nanomaterials is published online in Environmental Health Perspectives (EHP), the journal of the National Institute of Environmental Health Sciences (NIEHS). It is the first multi-institutional study examining the health effects of engineering nanomaterials to replicate and compare findings from different labs across the country.
The study is critical, the researchers said, because of the large quantities of nanomaterials being used in industry, electronics and medicine. Earlier studies had found when nanomaterials are taken into the lungs they can cause inflammation and fibrosis. The unique contribution of the current study is that all members of the consortium were able to show similar findings when similiar concentrations of the materials were introduced into the respiratory system. The findings should provide guidance for creating policy for the safe development of nanotechnology.
“This research provides further confirmation that nanomaterials have the potential to cause inflammation and injury to the lungs. Although small amounts of these materials in the lungs do not appear to produce injury, we still must remain vigilant in using care in the diverse applications of these materials in consumer products and foods,” said Kent Pinkerton, a study senior author and the director of the UC Davis Center for Health and the Environment.”
Used for their ability to confer strength and flexibility because of their tubular and spherical structures, the ubiquitous and highly malleable materials may be composed of everything from carbon to gold. The current study examined the health effects of inhaling two types of nanomaterials, those made from forms of titanium dioxide and those made from multi-walled carbon nanotubes, a substance with a tensile strength 100 times stronger than steel.
Titanium dioxide (TiO2) nanoparticles have already been found to cause systemic genetic damage in mice, according to an earlier comprehensive study conducted by researchers at UCLA's Jonsson Comprehensive Cancer Center.
The TiO2 nanoparticles induced single- and double-strand DNA breaks and also caused chromosomal damage as well as inflammation, all of which increase the risk for cancer.
Environmental pollution including carbon particles emitted by car exhaust, smoking and long term inhalation of dust of various origins have been recognised as risk factors causing chronic inflammation of the lungs. The link between smoking and autoimmune diseases such as rheumatoid arthritis has also been established. This new research now raises serious concerns in relation to similar risks caused by nanotechnology products which if not handled appropriately may contribute to the generation of new types of airborne pollutants causing risks to global health.
All types of nanoparticles have been found in human cells to manifest in the specific transformation of the amino acid arginine into the molecule called citrulline which can lead to the development of autoimmune conditions such as rheumatoid arthritis.
In the transformation to citrulline, human proteins which incorporate this modified amino acid as building blocks, can no longer function properly and are subject to destruction and elimination by the bodily defence system. Once programmed to get rid of citrullinated proteins, the immune system can start attacking its own tissues and organs, thereby causing the autoimmune processes which may result in rheumatoid arthritis.
Other diseases associated with inhaled nanoparticles include asthma, bronchitis, emphysema, lung cancer, and neurodegenerative diseases, such as Parkinson's and Alzheimer's diseases. Nanoparticles in the gastrointestinal tract have been linked to Crohn's disease and colon cancer. Nanoparticles that enter the circulatory system are implicated in arteriosclerosis, blood clots, arrhythmia, heart diseases, and ultimately death from heart disease. Nanoparticles entering other organs, such as liver, spleen, etc., may lead to diseases of these organs.
It was difficult to separate hype from reality when it all began, and almost no one worried about safety and nanotoxicology became established as a discipline in 2005 (Nanotoxicity: A New Discipline, SiS 28). By then, many serious health impacts had already been observed in laboratory experiments; and more appeared in subsequent years.
According to the the U.S. National Science Foundation, the nanotechnology market could reach over $3 trillion by 2015. This, says Dolez, corresponds to about millions of workers involved in nano-related activities. She adds that it has already been shown that nanoparticles may affect biological activity through oxidative stress at the cellular and molecular levels, although these effects are yet to be manifest as health problems among workers. The anticipated hazards associated with this incredibly diverse range of substances falling under the general and broad tag of "nanomaterials" remain largely unknown. And, some scientists have suggested that we are vigilant to emerging health problems associated with nanomaterials. The U.S. government recently updated its National Nanotechnology Initiative strategic plan to highlight the need for an assessment of nanomaterials toxicity before production begins.
The Environmental Working Group who previously analyzed 15 studies on nanoparticles on sunscreen said that no investigations have ever assessed absorption through damaged skin. Such data is missing “for nearly all of the 17 sunscreen chemicals approved for use in the U.S. ”
Philip Moos and colleagues note that there is ongoing concern about the potential toxicity of nanoparticles of various materials, which may have different physical and chemical properties than larger particles. Barely 1/50,000 the width of a human hair, nanoparticles are used in foods, cosmetics and other consumer products. Some sunscreens contain nanoparticles of zinc oxide. The scientists note that a concern is children accidentally ingesting nano-sized zinc oxide.
Their experiments with cell cultures of colon cells compared the effects of zinc oxide nanoparticles to zinc oxide sold as a conventional powder. They found that the nanoparticles were twice as toxic to the cells as the larger particles.
Nanoparticles, Natural, Artificial, Old and New
What’s new about nanoparticles, as far as risk is concerned, is that many of them are chemically inert as ordinary ions or as larger particles (and hence never had to go through regulatory approval before the nanoparticles were used); but as soon as the particle size reaches nanometre dimensions, they acquire novel physicochemical properties, causing oxidative stress and breaking DNA, and they can get access to every part of the body including the brain, via inhalation and the olfactory nerve.
A comprehensive review by Cristina Buzea and colleagues at Queen’s University, Kingston, Ontario, in Canada, pointed out that human beings have been exposed to natural nanoparticles since the origin of our species, in the form of viruses, dusts from terrestrial and extraterrestrial dust storms, volcanic eruptions, forest fires, and sea salt aerosols (which are largely beneficial).
Nanoparticles have been created by human activities for thousands of years, by burning wood in cooking, and more recently, chemical manufacturing, welding, ore refining and smelting, burning of petrol in vehicles and airplane engines, burning sewage sludge, coal and fuel oil for power generation, all of which are already known to have health impacts. Automobile exhaust particular pollution is linked to heart and lung diseases and childhood cancers.
There is clearly an urgent need not only to stem but also to reverse the unregulated tide of nanoparticles that are released onto the market. In view of the existing evidence, the following actions should be taken.
- Engineered nano-ingredients in food, cosmetics and baby products for which toxicity data already exist (e.g., silver, titanium oxide, fullerenes, etc.) should be withdrawn immediately
- A moratorium should be imposed on the commercialization of nano-products until they are demonstrated safe
- All consumer products containing nanotechnology should be clearly labelled
- A robust regulatory programme on nanotechnology - including characterisation and standardisation of manufacture - should be implemented as soon as possible
- There should be earmarked funding for research into the hazards of nanotechnology.
Marco Torres is a research specialist, writer and consumer advocate for healthy lifestyles. He holds degrees in Public Health and Environmental Science and is a professional speaker on topics such as disease prevention, environmental toxins and health policy.