Not enough data to assess risk for nanoscreens?

I’m glad to see that the Friends of the Earth (FOE) civil society group (or nongovernmental agency) have responded to Andrew Maynard’s challenge. As I thought, the FOE has stated that it is impossible to assess the risk that nanoscreens (specifically the sunscreens’ titanium dioxide and/or zinc oxide nanoparticles) present as there is not enough data.

The statement (posted in a June 15, 2010 posting on the 2020 Science blog) was made in response to a challenge by Dr. Andrew Maynard (blog owner) first issued in his June 8, 2010 posting (Friends of the Earth come down hard on nanotechnology – are they right?) and further detailed in another June 8, 2010 posting (Just how risky could nanoparticles in sunscreens be?).

FOE goes on to detail some of the problems associated with providing an answer (you can view the full statement in the first link provided in the second paragraph),

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.

I don’t think the sarcasm with which the authors (Georgia Miller and Ian Illuminato) open their statement is absolutely necessary but their main point is well made as it opens the door to a discussion about one’s perspective on and philosophy towards risk.

The impact that engineered nanoparticles of any kind could have on life is poorly understood and research is urgently needed. The research that has been undertaken on titanium dioxide and zinc oxide nanoparticles does suggest some potentially serious problems could occur. I want to emphasize my phrasing here ‘could occur’ because to date we have no evidence that anyone using nanoscreens has had any health issues as a consequence of their use. Still, the laboratory research is concerning. So, how are we as a society and as individuals going to approach the risk?

The school of thought which supports the FOE’s application of the precautionary principle seems to be that any element of risk should curtail use until the engineered nanoparticles have been extensively tested and then declared safe. I’m not clear how testing under those conditions could ever proceed to human clinical trials. It would not be possible to test every single variable or, more importantly, every combination of variables which could result in a risk. The net result would be: no nanoscreens while people use possibly inferior to nanosunscreen products to protect themselves from the sun’s effects.

I’ve commented about the Environmental Working Group (EWG) and their assessment of nanosunscreens previously (here). Last year (2009), they, reluctantly, after an extensive meta analysis of the available research recommended nanosunscreens on the basis that there was no compelling data to suggest undue risks. The EWG has not adjusted its stance since then and, this year, are warning against sunscreens that use Vitamin A and oxybenzone as well as sunscreens that are applied in spray or powder forms.

In most circumstances I imagine that the FOE and the EWG would be natural allies as both NGOs are focused on health and safety issues. So it’s strange that the FOE did not mention the EWG report (as I noted here) in the FOE’s own 2009 report on sunscreens although they did cite research from Japan that supports the FOE’s position but was released after the EWG’s 2009 recommendations.

In the instance of nanosunscreens, there appears to be a sharp division of opinion between the two groups. I think this points to a major philosophical difference in their approaches to risk. Faced with identical (or almost so) data sets, the FOE wants to halt use until these nanoparticles are declared safe while the EWG suggests that these nanosunscreens might be safer than conventional products currently in the marketplace and recommends their use.

The approach as exemplified by the FOE is to insist on extensive testing and guarantees as to how and when nanotechnology-enabled products are safe before they ever get near the marketplace. This is the precautionary principle being applied. Given the complex environment we all navigate on a daily basis, I can certainly understand the stance. However, I am pragmatic by nature and since testing every single possible variable and combination of variables is impossible I am more inclined to consider the data that we currently have available as inconclusive. I have read some (not all) of the materials and I’ve noticed that the scientists’ conclusions are always expressed in very measured tones.

To illustrate my point about the “measured tones”, I’ve excerpted this from FOE’s response to Andrew’s challenge in the June 15, 2010 posting on 2020 Science,

FOE: 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.

The article is in Nature Nanotechnology (behind a paywall) and it’s the published version of Dr. Amanda Barnard’s work using a computer simulation to establish potential toxicity. From the Nature Nanotechnology article,

… using this technique [computer simulation] it is possible to draw direct comparisons between the SPF, transparency and potential toxicity of nanoparticles used in sunscreens, based on fundamental nanoscale properties, and optimize these parameters numerically. In general, optimization decisions of this type are usually based on product testing under expected usage conditions, but the results presented here do complement traditional product and consumer testing activities, and can also be applied to other thermal or chemical conditions, or applied to any other material where a trade-off is necessary when balancing efficacy, aesthetics and an undesirable side effect. [emphases mine]

I gather Dr. Barnard is viewing the use of a computer simulation in research as a complement and not as a replacement for or an equivalent to traditional testing. In an interview with Anna Salleh for the Australian Broadcasting Corporation Science Online website,

Dr Barnard found that the size and concentrations of nanoparticles that gave the best transparency and sun protection also gave the highest potential for production of free radicals.

“Where we have the highest sun-protection factor – and it’s pretty – it [the sunscreen] is also toxic, potentially,” she said.

“Ultimately we have to trade off. We can’t have our cake and eat it too.”

I’m not sure what sort of trade-off Dr. Barnard might be suggesting but it’s clear that she’s aware that the use of nanotechnology-enabled products such as nanosunscreens is not a simplistic ‘good (conventional sunscreens) vs. bad (nanosunscreens)’ situation.

Dexter Johnson makes note of the FOE’s response to Andrew’s challenge in his essay (Daring to Challenge NGOs on Nanotech Risk) on the Nanoclast blog with some pithy and thought-provoking comments.

I do have one major point of difference with Dexter, I find the FOE’s suggestion that the companies selling the nanosunscreen products should provide their testing information to be a good idea although I first saw it in a comment from Hilary Sutcliffe in the comments section of one of Andrew’s June 8, 2010 postings.

I do believe that NGOs are important players in the debate but the tenor of the FOE’s response to Andrew’s challenge makes it a little harder to hold on to that belief. From the June 15, 2010 posting on Andrew’s blog,

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. [emphasis mine]

I think the challenge was very constructive indeed.

I did comment on this latest sunscreen discussion last week, Part 1 and Part 2 where I discuss the nature of risk, uncertainty and nanosunscreens.

7 thoughts on “Not enough data to assess risk for nanoscreens?

  1. Georgia Miller

    Hi Frogheart

    Thanks for your contribution to this discussion. I just want to clarify one point for readers who didn’t read the Friends of the Earth (FOE) response to Andrew Maynard’s blog in its original context.

    Our suggestion to Andrew that he could play a more constructive role in this policy discussion was in relation to his issuing a challenge (his word) to FOE to come up with a single, worst case scenario estimate of harm to human health as a result of using nano-sunscreens. Andrew stated that he was challenging us to come up with this figure as a means to move the discussion about nano-sunscreens on to a more evidence-based footing.

    FOE’s point was that given extensive uncertainty about the hazard posed by nanomaterials used in sunscreens, potential exposure associated with their use, and how to reliably perform nano-specific risk assessment, challenging NGOs to be the ones to develop an accurate and quantified prediction of harm is placing the burden of proof on the wrong shoulders. This is not to take away from the valuable work and commentary that Andrew Maynard usually produces – just a specific criticism of his challenge in this instance, as misdirected.

    Georgia Miller
    Friends of the Earth Australia

  2. admin

    Hi Hilary! Thank you for dropping by and you relieve my mind. By the time I finished writing up the post I was beginning to wonder if I’d made any sense at all. Not on Twitter yet, but soon. Cheers, Maryse

  3. admin

    Hi Georgia! Thank you for dropping by and for the clarification. Coincidentally while you were composing this, I was at 2020 Science leaving a comment with a question you’ve just answered. Your response here casts a somewhat different light than your original wording (for anyone curious about this, please do visit the posting with the response at 2020 Science (http://2020science.org/2010/06/15/just-how-risky-can-nanoparticles-in-sunscreens-be-friends-of-the-earth-respond/). I did interpret Andrew’s challenge not as an attempt to place the burden of proof on the NGOs but rather an attempt to change the nature of the discussion and, hopefully in the future, consultation. My own sense is that a number of the interested parties (government agencies, elected officials, NGOs, business interests, etc.) have fallen into the habit of almost continuous confrontational communication with regard to the risks and so, in my imagination, Andrew was trying to nudge friendlies such as you into taking a different tack. (I await, with considerable interest, Andrew’s next post where he comments on the FOE response and perhaps reveals his intentions. Thank you and Andrew (for his posts) and the other commenters both here on this blog and on others. Cheers, Maryse

  4. Madeleine Love

    Re this line: “I’m not clear how testing under those conditions could ever proceed to human clinical trials.”

    And yet our children are exposed to these products untested and unlabelled.

    Parents won’t leap for joy over the suggestion that their children must be exposed to these products, lest a company’s opportunity to move forward in marketing these products for profit be stymied.

    To suggest that parents can make choices is ludicrous, since children are part of communities and their exposure to untested products depends on whose care they are in (childcare, friend’s house, sporting days, school) from day to day.

  5. admin

    Hi Madeleine! Thanks for reading and leaving a comment. I’m sorry that I gave you the impression I was that there shouldn’t be human clinical trials or testing for that matter. My comment was intended to point out a possible error in logic with the application of the precautionary principle and its application to testing. I’m glad you brought up the issue of labeling as it’s something I’ve been thinking about for several months and haven’t written about yet. I was surprised when I found out (last year or maybe in 2008) that the European Commission was not going to require that labels on cosmetics (I think sunscreens are classified as cosmetic products) that nano-sized ingredients would be specified. I can’t remember the reasoning for their decision very well but one factor may have been the lack of a definition for what constitutes a nanomaterial. ETA July 9, 2010: This part of my response has bothered me so I doublechecked and as of November 2009 engineered nano-scale ingredients in cosmetics must be labeled as such in Europe as per this news item (http://www.rsc.org/chemistryworld/News/2009/November/27110901.asp) in Chemical World. I apologize for the error in my part.
    It seems extraordinary but there aren’t any internationally accepted definitions yet. The US currently has two bills up for discussion about the definitions, one in the House of Representatives and the other in the Senate. There is also a public consultation about a working definition for Health Canada and a bill which includes a definition of 1 to 100 nm was tabled in Canada’s House of Commons earlier this year. I’m not sure about the situation in the UK and in Europe. I believe a House of Lords committee proposed a definition of 1 to 1000 nm for identifying a nanomaterial. As for any other countries, I know even less about their situations.

    If you haven’t already come across it, the Environmental Working Group (EWG) lists sunscreens with the ingredients along with recommendations. They do identify products that have nanoscale ingredients. Since it is a US-based organization and while I believe they try to give information about as many products as possible depending on where you live, you may not be able to find some of the products you’d prefer. As well, the EWG warns against other harmful ingredients notably Vitamin A and oxybenzone as I mentioned in my posting.

    I’m not sure how to respond to your comment about business or this “To suggest that parents can make choices is ludicrous .. ” as my posting was focused on more abstract issues such as risk and how research is represented. As it turns out I was planning to post today about an essay by a businessman on the proposed bills under consideration in the US (I bookmarked the essay late yesterday and didn’t see your comment until this morning). As for any commentary I might offer about parents, children, and risk, that is something I would have to think long and hard about before attempting. On a personal basis, I’m more concerned about the silver nanoparticles that are making their way into the water supply than I am about titanium dioxide or zinc oxide nanoparticles. You’ve given me much food for thought and I’m sorry I’ve gone on for so long. Cheers, Maryse

  6. Pingback: A few thoughts on business and nanotechnology « FrogHeart

Leave a Reply

Your email address will not be published. Required fields are marked *