Just how risky can nanoparticles in sunscreens be? Friends of the Earth respond

Last week, I posed Friends of the Earth a challenge – “What is your worst case estimate of the human health risk from titanium dioxide and/or zinc oxide nanoparticles in sunscreens?”  Georgia Miller of FoE Australia and Ian Illuminato of FoE in the US have kindly provided a detailed response.  Rather than just keep this as a comment on the original blog, I thought it deserved a wider airing – and so am posting it here.

I will respond to the response in a few days time.  In the meantime, I would be extremely interested in what others think of the use of nanoparticles in sunscreens, based on my original piece and Georgia and Ian’s piece below.  Please do comment – this seems to be an area that desperately needs some good and open discussion.

Andrew – thanks for the invitation to perform some complex risk assessment using several poorly understood variables. However we do have to point out that the world’s best minds don’t yet have enough information even to design reliable nanomaterial risk assessment processes, let alone to come up with a single ‘worst case scenario’ figure for long term health impacts of using nano-sunscreens.

The huge knowledge gaps plaguing nanomaterials toxicity and exposure assessment (along with preliminary studies suggesting the potential for serious harm) are key reasons for calls by Friends of the Earth Australia and United States for a precautionary approach to management of nanotoxicity risks.

We explain below why your risk assessment challenge is impossible given these data gaps. We also point out that given that different people with different skin types are likely to experience different exposure levels, positing any single ‘worst case scenario’ figure is inappropriate. Obviously you are aware of these serious limitations. This does prompt us to question the intent of your challenge.

Further, we strongly suggest that your challenge is directed to the wrong people. Why not demand that the manufacturers of nano-sunscreens provide you with the data to demonstrate that their products are safe? Why not challenge the regulators to explain their failure to keep nanomaterials that behave as extreme photocatalysts out of sunscreens?

Better yet, why not support a discussion about the role of the precautionary principle in the management of uncertain new risks associated with emerging technologies? Why not explore the importance of public choice in the exposure to these risks? Why not contribute to a critical discussion about whose interests are served by the premature commercialisation of products about whose safety we know so little, when there is preliminary evidence of risk and very limited public benefit? Transparent micron-particle sized zinc oxide sunscreens are commercially available; a recent article suggests most titanium dioxide nano-sunscreens on the market could be doing more harm than good. No-one need use nanoparticles in order to produce a cosmetically and functionally acceptable sunscreen.

Andrew, we respectfully suggest that someone of your expertise and stature could play a more constructive role in these debates – debates which should not be limited to a question of technical risk assessment.

Georgia Miller and Ian Illuminato
Friends of the Earth Australia and United States

Why determining a single figure for ‘worst case scenario’ health harm associated with using nano-sunscreens is not possible

In 2004 the UK’s Royal Society recommended that nanoparticles be treated as new chemicals, subject to new safety testing before they could be used in products, and face mandatory labelling. Six years on, none of those things have happened.

The development and validation of nano-specific risk assessment processes may take years. As the European Food Safety Authority pointed out last year in relation to the risk assessment of nano-foods: “Although, case-by-case evaluation of specific ENMs [engineered nanomaterials] may be currently possible, the Scientific Committee wishes to emphasise that the risk assessment processes are still under development with respect to characterisation and analysis of ENMs in food and feed, optimisation of toxicity testing methods for ENMs and interpretation of the resulting data. Under these circumstances, any individual risk assessment is likely to be subject to a high degree of uncertainty. This situation will remain so until more data on and experience with testing of ENMs become available” (EFSA 2009, p2-39).

When it comes to sunscreens, a key component of risk assessment – determining likely exposure – is not yet possible because we do not yet understand what quantities of nanomaterials may be absorbed into the skin from sunscreens and in what circumstances. Skin penetration studies to date have largely failed to look at important variables such as skin condition (including damage through sunburn, injury or eczema, or thin skin present in the young or elderly), skin flexing (eg through exercise) and the role of substances in sunscreens that can act as penetration enhancers by increasing skin permeability. Further, most skin penetration studies have used excised skin in in vitro studies which is likely to underestimate actual penetration.

In your earlier blog you point out that research by Professor Brian Gulson at Macquarie University and by scientists at Australia’s CSIRO which shows radio-isotope labelled zinc from sunscreens in the blood and urine of human volunteers is not yet published. True enough – also that these researchers are not yet able to say whether or not the absorbed zinc they detected is in particle or ionic form. Nonetheless, the results do show that zinc in sunscreens does not simply remain on the outer layers of dead skin cells, as some have claimed. Many questions remain: the one clear answer is that more research is required.

One interesting point about Brian Gulson’s study underscores the impossibility of determining any single ‘worst case scenario’ figure for health harm. Professor Gulson told the ICONN conference in Sydney this year that one woman with sensitive skin suspended her participation in the trial after four days due to an adverse reaction. The levels of isotope labelled zinc in her blood were also substantially greater than that of other people in the trial. Are people with sensitive skin more likely to experience substantially greater skin penetration by nano-ingredients in sunscreens? Could this put a minority of the population at greater health risk? We don’t yet know.

A further constraint on calculating your requested ‘worst case scenario’ figure is the paucity of long-term and multi-generational nanotoxicity studies. This is a very serious limitation. Potential health harm from exposure to many nanomaterials may be more likely to manifest in the long term, rather than immediately. This point was made in 2004 by global reinsurance giant Swiss Re (2004). Swiss Re emphasised that as with asbestos, the significant time lag between exposure to nanomaterials and the onset of health harm is the greatest challenge for insurers attempting to calculate risk.

You ask for a ‘worst case scenario’. One worst case scenario is the accelerated development of skin cancer in people using nano-sunscreens, despite their wearing sunscreens for sun protection. We are copying below an extract of comments made by Dr Maxine McCall of the Australian CSIRO to the ABC’s 7.30 Report in late 2008.

“There’s the concern that there could be free radical generation on the skin, potentially damage, when the nano particles get into cells in the body if they don’t dissolve,” Maxine McCall, head of the CSIRO’s nano safety research, said. “Because they could interact with proteins in the cell or with DNA which codes – which has the genetic information – the worst case scenario, I suspect, could be development of cancer. We don’t know. That’s what we’re trying to find out.”

Dr McCall told the 7.30 Report that it would be two to three years before the CSIRO could reach a conclusion on nano sunscreens. “At the moment, we just don’t have enough information to make informed decisions,” she said.

Nanomaterials that behave as photocatalyts have been found in five of six Australian nano-sunscreens tested by Barker and Branch (2008). Sunscreens containing both nanoparticle titanium dioxide and zinc oxide were demonstrated to have a photocatalytic effect. Some of these photocatalysts were so extreme that they accelerated sun damage to pre-painted steel roofs by up to 100 times. Clearly the effects on human skin of nano-sunscreen use will differ from a pre-painted steel roof. Will these extreme photocatalysts penetrate human skin and persist in particulate form in sufficient quantities to cause long-term health harm? We don’t know.

Another worst case scenario is harm to the developing brains and reproductive systems of unborn babies, following maternal exposure to sunscreens. If nanoparticles from sunscreens are absorbed into a pregnant woman’s bloodstream, it is possible that they could pass across the placenta to the unborn baby. A recent study showed that polystyrene nanoparticles up to 240nm in size can be transported through a human placenta [note to Andrew: in your earlier blog you state that this “research was aimed at working out how to get beneficial drugs to the fetus”. The motivation of the study is arguably irrelevant. However in this instance the study is clearly designed to explore the potential for risky nanoparticle exposure in utero].

Animal studies have found altered gene expression, harm to the brains and reproductive systems and minor neuro-behavioural alterations in mice born to mothers exposed to titanium dioxide nanoparticles. Will nanoparticles of titanium dioxide be absorbed from sunscreens into the bloodstreams of pregnant women in sufficient quantities, and will they persist in particulate form in sufficient quantities, to harm unborn babies? Again, we don’t know. This will require much further research.

In the meantime, regulators faced with substantive knowledge gaps struggle to formulate an appropriate public policy response to uncertain but potentially serious risks. Challenging community groups to calculate the technical risk of a worst-case scenario of wearing nano-sunscreens to justify their asking product manufacturers to undertake basic safety research seems more than a little retrograde.

43 thoughts on “Just how risky can nanoparticles in sunscreens be? Friends of the Earth respond”

  1. Thanks Georgia and Ian for your full reply. Funnily enough I had just been at the European Commission and had a meeting with a US manufacturer of sunscreens so was thinking about just this issue. A couple of years ago, as far as I understand it, in response to pressure, perhaps raised by some of your work, the regulator insisted that all manufacturers of sunscreen in the EU submit to them their full testing data so that they could assess once and for all the safety of the products. When they had reviewed this, which as far as I understand it, was extensive, they agreed that the nano sunscreens were indeed safe and kept them on the market.

    So I don’t share your concerns about sunscreens, despite the studies you cite, many of which do not appear to me quite as useful as they might in calculating an actual exposure hazard in sunscreens. However I do agree that because of the uncertainty posed by lack of data it would be in their and our interests for companies to be much more open about how they have come to the conclusions about safety and share their testing methodologies to add to the body of evidence about the safety of nanomaterials and the products they are used in. This is what we were exploring at the Commission in relation to Nano and Textiles and will explore in other areas in the coming year.

    You will of course say that this has to be mandatory and all evidence should be disclosed. I think this is unlikely in the short to medium term and also feel that greater disclosure in a form which makes sense to the public is valuable even if such a mandatory reporting scheme were in place and this is always going to be a voluntary process. Perhaps sunscreens would be a good starting place for this where IP issues are minimal, industry is confident of its ground and the product has a genuine benefit for a large number of consumers?

    Andrew regularly raises some of the very issues that you mention in your list in different fora and in his blog. But in this regard I think it is quite appropriate that your work should be the focus of just as much scrutiny as he puts everyone else’s and so welcomed his expert view on your paper. NGOs make an important contribution to this and other debates, but there has been a tendency in recent years for data to be cherry-picked and skewed to make a point, which for me undermines the credibility of a much needed countervailing voice in this discussion. NGOs like yourselves play an essential role in furthering debate in this area, but your views and agenda also deserve to be debated and dissected as any other interest group’s does, whether it be business, government, consumer groups, scientists, social scientists or any other. Only then is society and consumers served. Sadly what has happened is that nobody dare challenge NGOs and they are not able to contribute as fully as they might, so we often don’t get the quality of information and debate which is really needed.

  2. Hi Hilary,

    Thanks for your comments. Ofcourse Friends of the Earth and other NGOs welcome critical discussion and scrutiny of our work and arguments. It’s curious that you have the impression that no-one dares question concerns expressed by NGOs, that is the antithesis of my experience. To clarify – it was Andrew’s challenge to come up with a single figure for a worst case scenario health impact of using nano-sunscreens that we criticised – not his evaluation of our work or FoEUS’ report more generally.

    I think the key point here is that the scientific community simply doesn’t yet have the capacity to determine the safety or otherwise of nano-sunscreens. As stated in our blog, many experts including those in the European Food Safety Authority acknowledge we cannot even conduct reliable risk assessment on nanomaterials yet. This undermines claims made by nano-sunscreen manufacturers in Europe or elsewhere that the data they have to date demonstrates the safety of nanomaterials. Ofcourse it would help boost public confidence (and regulatory capacity) if company data were peer-reviewed and made public, although it seldom is.

    Faced with this uncertainty, and preliminary evidence of the potential for some nanomaterials to pose serious new risks, Friends of the Earth groups and many other NGOs have called for the precautionary principle to be applied, and for product manufacturers to bear the burden of proof in demonstrating safety.

    Ofcourse it not just NGOs who have called for nanomaterials to be treated as new chemicals, for safety testing of nano-ingredients before these can be used in products, for manufacturers to disclose publicly the results and methodologies used in safety testing, and for mandatory labelling of ingredients used in consumer products – these were all calls by the UK’s Royal Society in 2004.

    1. That’s interesting about your view of people not daring to challenge ngos. I can see why it might look like that too. Maybe it is both!

      Re Andrew’s request, I did think that rather a gift question to you in the circumstances! The reasons you can’t are the reasons you have been giving all along!

      This concept of businesses bearing the burden of proof and how we get to see and trust there information was the focus of an event I was at in Brussels over the last few days. Part of the problem with this, is that it isn’t seen as realistic to envisage ngos trusting industry sponsored information, even peer reviewed and so there is genuine concern about sharing this testing to have it used against a particular technology or application even when it is valid, simply because it is paid for by companies and that doesn’t suit some agendas.

      That said, I agree with you that if companies want us to buy their products and trust that they have this sorted they need to demonstrate that fact much better, which will include sharing safety data, communicating about their use of the technology, its benefit and any uncertainties.

      However in a culture of confrontation on all sides I can see why that doesn’t happen either!

      I’m dizzy from the circles I keep going round in!

  3. Thank you all for this discussion. We have here 2 kind of issues. One is the “scientific” knowledge (are nano-sunscreens harmful?). This is a never endend issue. Science is a process and not a fact. The other issue, although hidden, is of great importance: focusing on a never ended scientific discussion is the field that corporations like, in the meanwhile the market of such products grows and consolidates, aside from any wondering of the needs for such new stuff; or better which percentage of the population will benefit in the case.
    The awareness of nanotech being introduced in the market prior to any social discussion did not come from industry (with industry R&D since the eighties) nor from the government (with substancial Public funds since 2000), but from several NGOs and Trade Unions (ETC group 2002 and after; FoE-A 2006, 2008; IUF, 2007; ICTA, 2007; ETUC, 2008, etc.). From 2002 to 2008 the industry & governments reply to these manifestations with 2 arguments: old regulation applies for unknown properties, and voluntary reports and code of conduct are enough. After mids 2008 things become to change, and governments are starting to think that some kind of fast regulation is needed. Moral of the story: without civil organizations monitoring the process technology will only serve those that profit from that.

    1. I agree with your conclusion Guillermo, though I do disagree about the development of regulation.

      However what I want is to find a way of cutting through the competing agendas and finding a way which doesn’t end in stalemate, but which delivers what we all want: safe products, which answer real needs and which do what they are supposed to. What happens is we are stuck in this endless ding dong of confrontation which is of course useful and perhaps necessary in the current culture, but isn’t as effective as it might be. All sides are to blame for that one.

  4. Hi All! Perhaps someone can help me understand where Andrew stated that he was challenging the FOE to come up with a number to force manufacturers to do some basic safety research as per this closing comment by Georgia Miller and Ian Illuminato, “Challenging community groups to calculate the technical risk of a worst-case scenario of wearing nano-sunscreens to justify their asking product manufacturers to undertake basic safety research seems more than a little retrograde.” Did I fail to see Andrew’s statement to that effect because all I saw was this request, “So here’s a question back to Friends of the Earth – based on the current state of the science, what number would you put on the risk to human health of using nanoparticle-based sunscreens under a plausible worst-case scenario?” from his first posting on June 8, 2010 and repeated on his second posting of that day?

    I have commented more extensively elsewhere (my own blog) about this response to Andrew’s challenge but I saved the question I posed previously for here. As for my own comments, (1) I appreciate the fact that this conversation is taking place and that you made the effort to respond, (2) I think your response points to basic philosophical issues about how we approach risk; (3) the tenor of your response did not sit well with me; and (4) while I have objections to some of the tactics used (an example taken from one of Hilary Sutcliffe’s earlier comments where she was speaking in a more general context, “cherrypicking and skewing data”) to make your points, I support your genuine desire to make the world a safer place. Thank you.

  5. Hi Georgia,

    I’m still intending to wait until more people have commented here (I live in hope!) before responding substantively to you response. But I couldn’t resist just making a couple of points:

    First, you are absolutely right that there are issues beyond risk assessment that need to be addressed here. But my aim here was to begin exploring risk specifically – not to the exclusion of the other issues, but as an important issue in itself in the decision-making process.

    Second, I’m afraid there was no hidden agenda to the question, unless I’m deluding myself – which is always a possibility! It may be because of my training, but I find it very hard to understand how decisions can be made without quantitative information – even if that quantitative information is somewhat speculative and subject to change. In fact, I would argue that the last 10,000 years of human development – probably longer – has been based on our ability to attach some form of comparative value to different options and, in a sense “run the numbers.” Without any sense of comparative value, decisions inevitably become driven by fear, ungrounded speculation and superstition. Which is why I think it is important to be able to place some comparative value on discussions over risk and safety when it comes to nanomaterials in sunscreens.

    Of course, we don’t have nearly enough information for a full quantitative risk assessment. But surely we have the intelligence to work through some plausible scenarios.

    Finally, I just wanted to be clear that I never expected a resource-limited organization like Friends of the Earth to support or conduct new research into potential risks. But I would like to see influential people and organizations in this debate evaluating available information in a way that helps support informed decision-making. That doesn’t require huge resources – especially when you can draw on experts in the field to help with the assessment.

    Anyway, enough from me for the time being – hopefully some others will chip in here.

    1. Thanks Hilary but don’t you think these two things might be related. Guy Cook has a section in his book based on discourse analysis of recurrent themes and word patterns that cropped up in interviews with university GM scientists and this revealed a strong tendency towards rigid stereotyping of NGO critics along lines that mean they’re viewed as impossible to constructively debate with, which seems similar to the message you report.

  6. Dear Friends,
    How wonderful to have so many smart, passionate experts engaged in a dialogue that forces each of us to be clear, be thoughtful, and be heard.

    Andrew, shame on you for tossing scientific ‘dirty bombs’ at a report by FoE that seeks to raise legitimate risk (hazard and/or exposure) concerns for the public to consider. I recommended the FoE report to friends, work colleagues, and reporters.

    Andrew and FoE folks, you are correct to seek to put some distance between the scientific discussion of calculated risks (dose-response) and uncertainty (lack of data, etc.) and the perception of risk, which is imbued with legitimate social values. For example, the issue of nanomaterials in sunscreens is far more than simply a numerical calculation – it is a legitimate consideration about whether we want to slather our children with product ingredients that have not undergone rigorous transparent (publicly-accessible) safety testing, regulatory review, and approval. Trust the experts? Are you kidding? Show me the data!

    I strongly support a dialogue that has space for both scientific calculations and values and perceptions of risk. We need to make that dialogue public, inclusive, transparent, and thoughtful. Risk is more than a number – its a face, a person, a community.

    Andrew, can your blog be a space for this kind of dialogue?

    1. Hi Jennifer,

      I hope 2020 Science is and can be a forum for opening up a dialogue for exploring these broader issues – they are important.

      As for the ‘dirty bomb’ – more of a provocative prod than a destructive force I hope :-)

  7. First, a disclaimer: These are my personal views and do not necessarily represent the views of my employer, US EPA.

    Second, given the current state of the data base on nanomaterials used in sunscreens, I don’t find very helpful statements such as “can penetrate skin” or “can damage colon cells.” How does someone on the one hand bemoan “huge knowledge gaps” and on the other hand make what seem to be such confident assertions? How are such assertions, within such a context, supposed to be useful to people have to make decisions related to the benefits and risks of products?

    Third, while data gaps indeed should be filled, I think an entirely different and even more important conversation also needs to take place. As we – industry, regulators, consumers, and other stakeholders – consider introducing new technologies and products into society, we should discuss why we need this new stuff, and what quantity and quality of both risk and benefit information we will deem acceptable before, during, and after we make decisions on the social desirability of developing and using the technology. Oh, and we also should have a discussion about who gets to decide.

    Maybe my twenty years of chronic exposure to the annoying buzz of the “yes it’s risky – no it’s not” argument is finally manifesting itself in the behavioral effects of irritation and impatience. I hope not. But I can’t help but feel that unless we get serious about moving the science, both physical and social, more upstream and providing decision makers with useful and useable tools for anticipatory or at least real-time technology evaluation, we’re never going to make real progress. Of course it takes more than tools – it requires political and social will. But that’s another blog.

  8. I am very disappointed that most of the remarks ignore the evidence and the science. As one of the inventors of a safe form of nanoparticulate titania that was developed by Oxonica and marketed by Boots in its Soltan range, I should point out the following:
    1) We invented the doped nanoparticles of titania because up to 2001, products on the market were mainly photocatalysts and could create free radicals that could cause skin damage or even skin cancer. This was the driver for our work….to make the sunscreens safer.
    2) We did this by applying physics and chemistry and selecting a dopant that made the titania a p-type semiconductor and hence made the formation of OH or other oxygen free radicals very unlikely. Many tests we performed proved our hypothesis.
    3) We were fairly confident that particles in the size range 20-80 nm do not penetrate the skin and many subsequent studies have proved this to be correct.

    Now I wonder what evidence the people who argue against this have…..they appear to rest their arguments on “opnion” rather than evidence. I am especially surprised by the stance taken by FoE. I was motivated by trying to make the world safer by understanding nanotechnology and designing a product based on science. Anyone who argues against the safety of a new product MUST produce the evidence and science….it is irresponsible not to do so.

    1. Well said Dr Dobson. It seems these fanatical groups are just that. They live in fear of the future and create fear in the public domain. They do not have evidence of their claims,they are not scientists, and rely on Google for fuel. Furthermore they all drive cars to work and live in the city. So,I ask you if friends of the earth were so hell bent on removing a fantastic new technology why don’t they go and live in the hills in tree houses,stop driving their cars and contribute to gas emissions and refrain from being hypocrites?

      I also noticed here that FOE has removed comments from people wishing to have their say that do not agree with them,a bit biased would you not think? Isn’t it freedom of information you seek? Dr.G Post

      1. Gerald – I’m afraid it was me who removed an earlier aggressive and inflammatory post, not FoE – I emailed the commenter suggesting they might like to rephrase and repost the comment as part of a more constructive dialogue

  9. Thanks very much to Professor Dobson and to Jeff Morris for adding their comments here. It is often difficult for people in organisations such as yours to comment in this way, and your perspective is assumed in a rather blunt way, rather than articulated clearly.

  10. I’d like to rise to Georgia and Ian’s more general challenge: “why not support a discussion about the role of the precautionary principle in the management of uncertain new risks associated with emerging technologies?”

    It seems to me that what’s wrong with the way the precautionary principle is being applied here is that it assumes that the world as it is is perfectly safe and perfectly sustainable. Such conservatism often isn’t appropriate – new technology may be replacing an existing technology which itself has risks and uncertainties. For example, as the implementation of REACH in the EU has revealed, full safety data does not yet exist for a great many chemicals which have been in common use for many years. In general, not doing something new is itself a choice which may have a cost of its own, and its own uncertainties attached to these costs and risks.

    I’d suggest asking the following three questions for a better application of the precautionary principle to a new technology:

    1. what are the benefits that the new technology provides – what are the risks and uncertainties associated with not realising these benefits?
    2. what are the risks and uncertainties attached to any current ways we have of realising these benefits using existing technologies?
    3. what are the risks and uncertainties of the new technology?

    So rather than just considering question 3, as is often implicitly done now, these three questions need to be weighed up together.

    Here’s how this might work for a couple of examples.
    Using fullerenes as antioxidants in face creams – under 1, we’d ask ourselves how much actual benefit we get from the face cream, including any actual real effect, if any, and the psychological benefit some people seem to get from being able to spend lots of money on products supported by superficially impressive but ultimately unconvincing sciencey advertising. Then, we’d compare this with the risks of other comparable products. And finally, we’d look into the risks and uncertainties of putting fullerenes on our face. I think in this case it’s obvious which way the precautionary principle is going to point.

    For the use of nanoscale titanium dioxide in sunscreen, we’d start by quantifying the dangers of skin cancer from excessive sun exposure, and setting this against the various benefits people take from going outside in the sun. Then we’d be weighing up the dangers of existing, non-nano, sunscreen ingredients, noting that typical small-molecule UV filters are much more likely to be able to penetrate skin than nanoparticulates, that frequently used ingredients like oxybenzone and octyl methoxycinnamate are known hormone disrupters, and that a number of commonly used UV filters only screen UVB, continuing to allow damaging UVA to reach the skin. It’s in this context that we should then look at the risks and uncertainties of nano-ingredients, noting also that these risks won’t be generic for titanium dioxide, but will depend on crystal structure, doping and the particle’s surface coating. Now it’s much less obvious that precaution dictates not using nanoscale titania. Personally, I follow the advice of the USA’s Environmental Working Group and positively seek out products like Soltan in preference to sunscreens without nano ingredients, not in the belief that they are completely risk-free, but because I think this risk is considerably smaller than the risk of unprotected sun exposure or that from non-nano UV filters.

  11. Thanks for an interesting, informative and well tempered debate. I would like just to respond to Hilary Sutcliffe’s surprising comment about nobody daring to challenge the views of NGOs. Whole books have been written about the “backlash” against environmental groups, like Friends of the Earth, and the way in which they’ve often been labeled as, at best, “unscientific”, “irrational” and “extreme”, and at worst as “fundamentalists”, “fanatics” and “Luddites”. Guy Cook’s book on the discourse of the GM debate, Genetically Modified Language, is particularly good on this – see, for instance, chapter 2 where he analyses a speech to the RS by Robert May. George Monbiot’s also just published a couple of pieces on what he claims have been the large number of mostly uncritical reviews of Matt Ridley’s new book (Ridley of course has aggessively attacked environmental NGOs, even calling them “Gestapo”). Monbiot suggests that the reason for Ridley’s generally easy ride is that, unlike the environmental movement, he’s telling people – especially rich, powerful people – what they would like to hear: http://www.guardian.co.uk/commentisfree/cif-green/2010/jun/18/matt-ridley-rational-optimist-errors

  12. Thanks Sam, you may well be right and I look forward to reading these references. However I’m not really meaning the general anti-ngo feeling you are talking about which I agree is just unhelpful, though in the area I work in I don’t see much of to be honest. But when organisations, mainly businesses and government avoid constructively debating with those who they may feel have been misjudged them or mislead the public in some way. When I ask why, if they feel they have been misrepresented, they don’t counter the arguments or give us the information we need to make a judgement ourselves, (particularly in the way Andrew has done here), the answer is usually that to engage in a critical way is always going to be misrepresented and it is impossible to challenge an ngo without being the bad guy, so they don’t, which I think is possibly correct, but also means we do not get the quality of debate or of information we need.

  13. Brian Gulson – lead researcher in the Australian sunscreen study cited by Georgia above – asked me to post these clarifications on his study:

    Our study involved two sunscreen formulations containing zinc (Zn) oxide particles (‘nanoparticles’ and ‘bulk’) highly enriched with a stable Zn isotope 68Zn. These sunscreens were applied to the backs of 20 volunteers twice daily over 5 days in an outdoor setting (i.e. with UV exposure). Blood and urine were collected prior to sunscreen application, at various times during the trial, and 6 days after the trial ended. Detection of the 68Zn tracer in blood and urine indicates penetration through the skin.

    Some other observations of relevance to the present discussion are:

    1. Previous studies did not measure blood and urine.
    2. The amounts of the 68Zn tracer detected in blood and urine were very small (micrograms of Zn) compared with the normal amount of Zn in blood (milligrams). Even if one considers other compartments or tissues in the body (e.g. liver) which can exchange Zn rapidly with plasma and red blood cells, these potentially larger amounts of tracer would still be small compared with the total amount of Zn in the body.
    3. The small amounts we observed would probably not be detectable in the other studies using less sensitive methods. Furthermore, without using an isotope tracer, they could not distinguish between Zn coming from the sunscreen and that introduced into the body from diet or Zn already circulating in the body.
    4. Very low levels of 68Zn tracer were first detected in blood following the 4th application of sunscreen, and ~30 hours after the 1st application. This sets a time frame for measuring dermal penetration by sensitive methods, and may help with the analysis of other studies involving fewer applications and/or shorter detection times following applications.
    5. The biggest question remaining from our study is that we don’t know whether the 68Zn we detected in blood and urine is as ZnO nanoparticles or as soluble Zn.
    6. The adverse reaction of one subject is of interest. During the sunscreen-application phase, we noticed a skin reaction where sunscreen had been applied, and at that point we made the decision to apply no more sunscreen to her; however, we continued to sample her blood and urine. At the time of this observation, she told us that her skin commonly reacts to sunscreens and skin-care products.
    1. Brian,

      Thank you for the clarity and information regarding the increased level of Zn from your study.

      I noticed that the FOE rely on this study to support their argument, however they leave out reference to important information in the study, that being the the bulk group and the nano group both showed increased signs of Zn in the blood and Urine of the participants and the study mentions that there was “NO STATISTICAL DIFFERENCE BETWEEN THESE LEVELS.”
      This would seem to indicate that both forms of Zno assisted in increased levels of Zn in the blood stream and urine.

      The information FOE circulate in their sunscreen guide seems to contradict the information they rely on to support their claims citing this study as proof that “nano sunscreen penetrates the skin “and that the TGA should “…close the legal gaps..”

      However if they were to take the full facts of that study into consideration they would see that the sunscreens they recommend in their ” green ” non-nano category also penetrate the skin, or more factually also create increased levels of Zn. This to me,is mis-information from the FOE and misleading to the general public.

      Turning scientific information into a witch hunt is something we should have evolved out of after the dark ages…

      1. Hi there Gerald,

        Just to clarify, we think Brian Gulson’s study is interesting as it disproves the TGA’s assertion that nanoparticles remain on the outer layers of dead skin (ie there is no risk of exposure to them). The TGA has in the past acknowledged the growing evidence of toxicity and photocatalytic behaviour of some nanoparticles used in sunscreens. However it has rejected calls to require companies to do safety testing on the basis that exposure won’t occur. The Gulson et al study doesn’t establish whether or not skin uptake of zinc occurred in nanoparticle or ionic form. But it does establish that the zinc wasn’t just remaining on the outer layers of dead skin, as asserted by the TGA.

        It is interesting that the Gulson et al study found no statistical difference between skin absorption by nanoparticles compared to their control particles. But I wouldn’t draw too many conclusions from this. The control particles had an average particle size of 110nm (± 46 nm; minimum 25 nm, maximum 284 nm).

        In any case, our key interest is in whether the risks associated with nanoparticle exposure are greater than those associated with larger particles. As we have discussed elsewhere in these posts, there is evidence that in relation to some nano-sunscreens, that is the case. Not all nanoparticles will be dangerous, but given that their toxicity cannot be predicted from the toxicity of larger particles of the same composition, there is a strong argument for requiring manufacturers to conduct safety testing of the nanoparticles before using these ingredients in commercial products. The preliminary evidence that sunscreen ingredients do not all stay on the dead outer layers of skin adds weight to these calls.


        1. Hi Georgia,

          You say this study disproves the TGA’s position of “nano particles remaining on the outer service of the skin”. I think you should read the study again, as I can see no evidence supporting your claim.

          In fact the point I was trying to make is that the sunscreens you recommend which use a micronised Zno (>100 nm ) statistically showed the same level of Zn , not nano particles in the blood and urine.

          Lets try to keep this scientific and not speculative.


          1. Gerald-This is very interesting and raises concerns about the position FOE have taken, where can I find this study result please? I also would like to know why the FOE have kept these findings secret from the public? Georgia-you seem to stand behind your words of
            ” In any case, our key interest is in whether the risks associated with nanoparticle exposure are greater than those associated with larger particles.” To my understanding larger particles are also a form of nanotech? Aren’t you interested in the health of the consumer? Isn’t this why you began this campaign? Hmmm?

        2. Georgia, I have read the study mentioned here and debated by Gerald. I am concerned about your comments or should I say lack of comments, and the confusion surrounding actual particle size and penetration of zinc not nano particles. I understand the quote made by Andrew Maynard in reference to the FOE’s recommendations :
          We’ll have to wait for the paper to be published before any firm conclusions can be drawn from this work. But if dissolution is the dominant mechanism here, it suggests that sunscreens relying on larger ZnO particles (and, coincidentally, recommended by Friends of the Earth), may lead to just as much zinc getting into the body as those using nanoscale ZnO particles.

          Read more: http://2020science.org/2010/06/08/friends-of-the-earth-come-down-hard-on-nanotechnology-are-they-right/#ixzz14qP6sdUi

          I am sure many are eager to hear your response to this please. Making claims you cannot support is frankly discrediting yourself and your organisation,don’t you think?

          1. Hi all

            The study has been published and I have posted the link to this study previously. Here it is again: http://toxsci.oxfordjournals.org/content/early/2010/08/12/toxsci.kfq243.abstract?related-urls=yes&legid=toxsci;kfq243v1.

            Our concerns about the novel behaviour of nanoparticles are detailed elsewhere on this page. FoE’s calls for nanoparticles to be subjected to safety assessment as new chemicals prior to being permitted in sunscreens and other commercial products, and to face mandatory labelling, are consistent with recommendations made by the UK Royal Society.


  14. Professor Tilman Butz – an expert in nanoparticle penetration through the skin and the project leader of the (now finished) EU Nanoderm Project – asked me to post these comments:

    Comments concerning dermal penetration of nano-sized physical filters in sunscreens.

    In use are TiO2 and sometimes ZnO with primary particle sizes around 20 nm. They have a weight in the order of 1 MDa (1 million Daltons = weight of 1 million hydrogen atoms, expressed in molecular terminology although the particles are not molecules). There is general agreement that 0,5 kDa is the upper limit for dermal penetration. Hence, these particles are much too large (heavy) for dermal penetration. The situation could change if much smaller particles were in use. Thus far, this does not seem to be the case. The material which is produced by flame pyrolysis probably is devoid of smaller particles (say 2 nm) because they fuse with larger ones already during the production. Particles with 20 nm diameter (which usually agglomerate) do not diffuse through the horny layer, rather they are mechanically rubbed in between the first corneozyte layers and into hair follicles.

    The high-temperature TiO2 nanomaterials (both anatase and rutile) are photocatalytically active, a property which is used in waste-water purification but which is undesirable on skin. Therefore such particles are coated with e.g. alumina or amorphous silica. Uncoated TiO2 nanoparticles should not be used in sunscreens (unfortunately this is not always obeyed).

    There are large data gaps concerning skin with impaired barrier function. Some data exist for psoriatic skin and also sunburned murine skin. No data seem to exist for atopic skin.

    A point which deserved special attention is that the sunscreens do not cover the horny layer uniformly, i.e. there are small areas which are not protected at all (maybe due to sweat or wrinkles). In these areas UV-light will definitely cause damage. The immune system apparently can cope with this damage because there are no visible “mini-sunburns”. However, skin is an unforgiving organ and, hence, long-term exposure could lead to effects even when always being protected by sunscreens.
    My recommendation: do use sunscreens, also with physical UV-filters, but avoid excessive exposure to sunlight.

    Leipzig, 13.7.2010

    Prof. Dr. Tilman Butz
    University of Leipzig, Germany
    Faculty of Physics and Earth Sciences

  15. Who said size doesn’t matter? If only Professor Butz’s comments would be the end of the debate, but I suspect nanophobia will persist and the company marketing departments will flee in fear from the activists in the same way that they did from GMO. They’ll label their products nano-free as if they hadn’t simply latched on to a scientific buzzword for the sake of sales in the first place…

  16. Please, please, please! I’m sure I’m not the only one anxiously waiting for “nano-free” sun screen! The nano industry is heavy on marketing and extra-lite on safety.

    Be disparaging if you need to, but give us a damn choice.

  17. I believe this line by Georgia and Ian was grossly misleading:
    “Transparent micron-particle sized zinc oxide sunscreens are commercially available; a recent article suggests most titanium dioxide nano-sunscreens on the market could be doing more harm than good.”

    Upon reading the article, I found that it stated no such thing. In fact, it said:
    “A visual inspection of Fig. 4 suggests that the only combination of particle size and concentration that will remain functional (delivering superior efficacy and high transparency) while offering low relative toxicity is a large amount of very small particles.”

  18. Hi all,

    Just a quick response to Steve DeWitt’s comment. Our statement that “a recent article suggests most titanium dioxide nano-sunscreens on the market could be doing more harm than good” is entirely warranted by the study we cited (available at http://www.nature.com/nnano/journal/v5/n4/abs/nnano.2010.25.html).

    Dr Amanda Barnard from Australia’s CSIRO used modelling to investigate the transparency, sun protection capacity, and production of ROS (free radicals) by titanium dioxide nanoparticles 3-200nm in size. She used this size range as it is the most common for sunscreens. Her modelling found that the risk of free radical production in most is likely to cancel out the benefit of sun protection in titanium dioxide particles greater than 13nm in size. That is, in the majority of nano-titanium dioxide nano-sunscreens on the market, as we stated.

    Further, Dr Barnard does not assert that nanoparticles <13nm are safe, as she looked only at ROS production; her article acknowledges that there may be other relevant toxicity mechanisms that require investigation.

    Steve DeWitt quote only a sentence from Dr Barnard's article. The context of the statement he quotes is as follows:
    "Avisual inspection of Fig. 4 suggests that the only combination of
    particle size and concentration that will remain functional (delivering
    superior efficacy and high transparency) while offering low relative
    toxicity is a large amount of very small particles. This can be
    confirmed by performing a numerical optimization of the solutions
    (assuming equal importance is placed on each), and plotting in the
    same kD, Cl plane, as shown in Fig. 5. In this plot it can be seen that the
    very small optimal region of the 90th percentile (shown in red), where
    the nanoparticles are most functional (regarding their ability to block
    UV light, although remaining transparent to visible light), but present
    minimal potential for toxicity, is a loading of over80 109 nanoparticles
    with an average diameter of ,13 nm. However, the only
    measure of toxicity that is included here is possible ROS generation,
    and small nanoparticles of this size may present a health risk for a
    variety of other reasons due to factors that are not included in this
    work. Caution should therefore be exercised."


  19. Hi All, jumping in here to have my say! I am not a scientist,nor can I claim any experience or make assumptions regarding nanotechnology,except to say that after much debate and personal research, I think nano sunscreens are the most efficient and will continue to use for my family. I am a Clothing retailer/business owner and in these poor economic times, I have to say I am dissapointed in the vindictive approach the FOE take where companies wish to remain discreet. I mean Georgia really?? Telling consumers to “get a refund” when you have no conclusive evidence? Shame on FOE. I have lost faith now in FOE so jump to more ethical groups that helped me find my way as I am not interested in emotional manipulation. I suggest to consumers not to be caught in the fear and emotion regarding this topic or rely on information from Activist groups that are contradictory and biased in their approach. Ask your doctor,they care about you and your health. Skin cancer is deadly far more than the use of nanotechnology,and the FOE fail to mention this when defaming the companies doing their bit to prevent it. I find the EWG is much more high integrity group,who at least do their research on efficacy on sunscreen products available. They actually care about the health of their consumers and I find have a more realistic approach. http://www.cosmeticsdatabase.com/special/sunscreens/nanotech.php

  20. Plain Jane: this is from your link:
    “Until the consequences of nanoparticle exposure are fully studied, EWG urges manufacturers to label the particle size of zinc and titanium used in their formulations to allow consumers who want to avoid nanoparticle exposures options to do so. ”
    How is this different from what FOE suggest? Is product labeling about company discretion or consumer information?

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