Increasingly, sunscreen makers are using nanomaterials -- man-made substances that are engineered at the atomic or molecular scale -- to do one thing: make white sunblocks rub clear.
But three consumer and environmental groups have raised serious concerns about this practice in a new report that cites lacking or worrying health studies about these nanomaterials. Nanotechnology is hardly regulated in the U.S., though the very properties that make nanotechnology so appealing to manufacturers -- that substances manipulated at the nano-scale have different properties than the same substances manipulated at larger scales -- may produce novel health risks.
The presence of nanomaterials does not make sunscreens more effective, according to testing by Consumers Union, publisher of Consumer Reports, and one of the groups raising concerns about sunscreens, along with Friends of Earth and International Center for Technology Assessment. The groups' assessment: "When you look at the data, its clear that sunscreens containing nanomaterials are not worth the risk."
Frustratingly, this claim runs counter to the widely reported list of sunscreens recommended by the Environmental Working Group. The Daily Green published a feature highlighting EWG's recommended sunscreen brands, and will update it with information about nanotechnology used by those brands' manufacturers. The Environmental Working Group's studies included effectiveness and the presence of a variety of suspect substances, but it did not mark down sunscreens if they contain nanomaterials.
"When we began our sunscreen investigation at the Environmental Working Group, our researchers thought we would ultimately recommend against micronized and nano-sized zinc oxide and titanium dioxide sunscreens," the Environmental Working Group reported. "After all, no one has taken a more expansive and critical look than EWG at the use of nanoparticles in cosmetics and sunscreens, including the lack of definitive safety data and consumer information on these common new ingredients, and few substances more dramatically highlight gaps in our system of public health protections than the raw materials used in the burgeoning field of nanotechnology. But many months and nearly 400 peer-reviewed studies later, we find ourselves drawing a different conclusion, and recommending some sunscreens that may contain nano-sized ingredients."
The groups behind the new report see it differently.
"I personally very much respect the work that EWG does, but in this case we choose a different direction and have continued to highlight the risks involved with nanomaterials, because they do exist, as we explain in the report," said Ian Illuminato, a Health and Environment Campaigner for Friends of Earth, which like Environmental Working Group, is a founding member of the Campaign for Safe Cosmetics.
In Consumer Union tests, some of the highest-rated Environmental Working Group sunscreens were not nearly as effective as advertised, according to Michael Hansen, a senior scientist at Consumers Union. EWG based its efficacy assessments on the types and concentrations of active ingredients used, but the Consumers Union analysis found that the actual real-world formulations make a big difference and undercut the validity of the EWG findings.
There's simply no one list of products consumers can turn to, if they want an effective sunscreen that avoids both the potentially toxic traditional ingredients highlighted by EWG's guide (like avobenzone and oxybenzone) and the untested nanomaterials (zinc and titanium oxides, primarily) highlighted by the new report. Ugh.
Further, consumers cannot trust the claims -- made on labels or directly from company representatives -- that their products are free of nanomaterials, according to Hansen. Consumers Union testing found nanomaterials in several brands that advertised or stated that they shun these substances.
In other words, there's still a lot of confusion on this topic, and that makes it confusing to consumers trying to make a wise and healthy choice in the marketplace.
The new report lists these 8 reasons to be wary about nanotech in sunscreens:
1. Nanomaterials are different from other conventionally-sized compounds
Materials manufactured at the nanoscale can exhibit different physical, biological, and chemical properties than bulk materials (e.g. stable compounds can become highly reactive; relatively benign substances can become more toxic). One reason for these fundamentally different properties is that quantum physics governs at the nanoscale. But just as the size and chemical characteristics of manufactured nanomaterials can give them exciting properties for manufacturers, those same new properties tiny size, vastly increased surface area to volume ratio, high reactivity can also create unique and unpredictable human health and environmental risks. Compared with their normal-scale counterparts, the small size of nanomaterials can increase their ability to penetrate biological tissues and their large surface area-to-mass ratio can increase their potential reactivity.
2. In the body, nanomaterials have much greater access to vulnerable organs and tissues.
Although very few nanomaterials have been adequately tested, from the limited data available, its clear that many can be more bioavailable than larger compounds. Their small size can make them more amenable to entering the lungs, if inhaled, passing through cell membranes, and in some cases penetrating the skin. When ingested, some nanomaterials may pass through the gut wall and circulate through our blood. Once in the blood stream, many seem to have unlimited access to tissues and organs, including the brain and even the developing fetus, where they may disrupt normal cell activity. Animal studies suggest that some nanomaterials once in the body, can cause inflammation, damage brain cells and cause pre-cancerous lesions. Ultrafine air pollution, much of which is nano-sized, is associated with reduced lung function and increased likelihood of asthma, respiratory disease, and deaths from lung and heart disease.
3. Increasing evidence that some nanomaterials can pass through the skin
Though studies to date suggest nanoscale mineral compounds in sunscreen may not fully penetrate intact skin, government agencies worldwide are still investigating this route of exposure. Scientific studies with other experimental nanomaterials have shown that some skin penetration can occur under various conditions, such as4 if skin is flexed (as during exercise), or if other ingredients are present which enhance penetration6 (as may be found in certain cosmetics). Damaged skin can take up particles 70 times bigger than a nanoparticle, suggesting that skin penetration by nanomaterials is likely to occur in people with eczema or acne. Recent research has shown that skin penetration is also more likely in sun burnt skin. We do not yet know if common nanoscale ingredients would more likely penetrate thinner skin e.g. in elderly people or babies or whether deep penetration would always be necessary to elicit any possible toxic effects that may occur.
4. Senior scientists have called for mandatory premarket safety tests for nanomaterials before they are used in products
The United Kingdoms Royal Society, the worlds oldest scientific institution, has recommended that given the evidence of potentially serious and unpredictable health risks, nanomaterials should be treated as new chemicals and subject to new safety assessments before being allowed in consumer products. Yet, none of the nano-cosmetics or nano-sunscreens on the market are subject to a premarket safety assessment by the U.S. Food and Drug Administration (FDA) that would require special tests for effects unique to nanoscale ingredients, before being put on the shelves. While agencies in the U.S. have hesitantly acknowledged the possible dangers posed by manufactured nanomaterials, the European Union has taken action to protect the public. New rules passed in Europe on March 2009 will require some nanomaterials in cosmetics and sunscreens to be labeled on the ingredients list; the regulation will also require increasedsafety testing for cosmetics containing nanomaterials.
5. Potential next generation harm from nanomaterials
Two recent studies by Japanese researchers show the transfer of nanoparticles of titanium dioxide from pregnant mice to their offspring, following intravenous injection. One study shows brain damage, nerve system damage and reduced sperm production in male offspring, while another shows offspring suffer altered gene expression related to brain development. A study by US researchers has also found that pregnant mice exposed to titanium dioxide nanoparticles via inhalation also transfer these to offspring. This resulted in minor neurobehavioral alterations in offspring. These results are concerning because titanium dioxide is one of the most widely used nanomaterials, found in cosmetics, sunscreens, food packaging, paints, wall coatings, dirt repellant coatings for windows, car coatings, etc.
6. Workers and the Environment
A product which is potentially harmful to consumers can also have equal or even greater negative consequences for the environment and for those who actually create the product. Workers who manufacture, research, package, handle, transport, use and dispose of nanomaterials all potentially face nano-exposure. There is a limited number of peer-reviewed scientific studies on the health and environmental impacts of nanomaterials. However, there is preliminary scientific evidence that shows nano-ingredients in sunscreens could possibly harm both workers and the environment. Workers handling nanomaterials are likely to be exposed at much higher levels than the general public, and on a more consistent basis. There are currently no established safe levels of exposure to nanomaterials and no reliable systems and equipment to protect workers from harmful levels of exposure. Some inhalation and instillation studies have shown that titanium dioxide nanomaterials can cause lung inflammation and injury, or cytotoxicity in test rodents. This suggests that if workplace exposure is high, titanium dioxide nanomaterials could be hazardous for workers health. Moreover, once released into the environment, many nanomaterials may persist and accumulate as pollutants in air, soil or water. For example, a 2006 study demonstrated that some forms of titanium dioxide nanomaterials (popular ingredients in nanosunscreens) are toxic to algae and water fleas, especially after exposure to UV light. Algae and water fleas are a vital part of aquatic environments and are often used by regulators as indicators of ecosystem health.
7. Nanomaterials in sunscreens and cosmetics could theoretically cause skin damage over time.
Scientific studies in laboratory animals and cell systems have shown that certain nanoscale materials of titanium dioxide and zinc oxide compounds commonly used in sunscreens and cosmetics can produce free radicals, damage DNA and cause cell toxicity, especially when exposed to UV light. Such findings raise concerns about the potential for these compounds to cause skin damage over time if such effects persist when these ingredients are used in product formulations.
8. Consumers can get highly effective transparent protection from harmful rays of the sun with products made without nanoscale chemical ingredients.
Adding nanomaterials means adding an unnecessary potential risk to our health and to the environment, with no significant gain. In 2007 Consumer Reports tested sunscreens containing nanomaterials and found no correlation between nanomaterial content and sun protection. Consumer Reports testing found neither nanoscale zinc nor titanium oxides provide a clear performance advantage over other active ingredients (though its not clear whether non-mineral, carbon-based formulations, are all nano-free). For example, most products containing avobenzone were at least very good at blocking UVA, but one was just good. Likewise, most products containing nanoscale zinc oxide provided at least very good protection against UVA, but one was only fair. In any case, sunscreens developed without nanomaterials have been shown to be effective at blocking the harmful rays of the sun. While questions do exist about safety of some other chemicals in sunscreens, nanoscale ingredients bring a whole new range of serious health concerns that need to be assessed.
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