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.