Tag Archives: coral reefs

Sunscreens: 2018 update

I don’t usually concern myself with SPF numbers on sunscreens as my primary focus has been on the inclusion of nanoscale metal particles (these are still considered safe). However, a recent conversation with a dental hygienist and coincidentally tripping across a June 19, 2018 posting on the blog shortly after the convo. has me reassessing my take on SPF numbers (Note: Links have been removed),

So, what’s the deal with SPF? A recent interview of Dr Steven Q Wang, M.D., chair of The Skin Cancer Foundation Photobiology Committee, finally will give us some clarity. Apparently, the SPF number, be it 15, 30, or 50, refers to the amount of UVB protection that that sunscreen provides. Rather than comparing the SPFs to each other, like we all do at the store, SPF is a reflection of the length of time it would take for the Sun’s UVB radiation to redden your skin (used exactly as directed), versus if you didn’t apply any sunscreen at all. In ideal situations (in lab settings), if you wore SPF 30, it would take 30 times longer for you to get a sunburn than if you didn’t wear any sunscreen.

What’s more, SPF 30 is not nearly half the strength of SPF 50. Rather, SPF 30 allows 3% of UVB rays to hit your skin, and SPF 50 allows about 2% of UVB rays to hit your skin. Now before you say that that is just one measly percent, it actually is much more. According to Dr Steven Q. Wang, SPF 30 allows around 1.5 times more UV radiation onto your skin than SPF 50. That’s an actual 150% difference [according to Wang’s article “… SPF 30 is allowing 50 percent more UV radiation onto your skin.”] in protection.

(author of the ‘eponymous’ blog) offers a good overview of the topic in a friendly, informative fashion albeit I found the ‘percentage’ to be a bit confusing. (S)he also provides a link to a previous posting about the ingredients in sunscreens (I do have one point of disagreement with regarding oxybenzone) as well as links to Dr. Steven Q. Wang’s May 24, 2018 Ask the Expert article about sunscreens and SPF numbers on skincancer.org. You can find the percentage under the ‘What Does the SPF Number Mean?’ subsection, in the second paragraph.

Ingredients: metallic nanoparticles and oxybenzone

The use of metallic nanoparticles  (usually zinc oxide and/or (titanium dioxide) in sunscreens was loathed by civil society groups, in particular Friends of the Earth (FOE) who campaigned relentlessly against their use in sunscreens. The nadir for FOE was in February 2012 when the Australian government published a survey showing that 13% of the respondents were not using any sunscreens due to their fear of nanoparticles. For those who don’t know, Australia has the highest rate of skin cancer in the world. (You can read about the debacle in my Feb. 9, 2012 posting.)

At the time, the only civil society group which supported the use of metallic nanoparticles in sunscreens was the Environmental Working Group (EWG).  After an examination of the research they, to their own surprise, came out in favour (grudgingly) of metallic nanoparticles. (The EWG were more concerned about the use of oxybenzone in sunscreens.)

Over time, the EWG’s perspective has been adopted by other groups to the point where sunscreens with metallic nanoparticles are commonplace in ‘natural’ or ‘organic’ sunscreens.

As for oxybenzones, in a May 23, 2018 posting about sunscreen ingredients notes this (Note: Links have been removed),

Oxybenzone – Chemical sunscreen, protects from UV damage. Oxybenzone belongs to the chemical family Benzophenone, which are persistent (difficult to get rid of), bioaccumulative (builds up in your body over time), and toxic, or PBT [or: Persistent, bioaccumulative and toxic substances (PBTs)]. They are a possible carcinogen (cancer-causing agent), endocrine disrupter; however, this is debatable. Also could cause developmental and reproductive toxicity, could cause organ system toxicity, as well as could cause irritation and potentially toxic to the environment.

It seems that the tide is turning against the use of oxybenzones (from a July 3, 2018 article by Adam Bluestein for Fast Company; Note: Links have been removed),

On July 3 [2018], Hawaii’s Governor, David Ig, will sign into law the first statewide ban on the sale of sunscreens containing chemicals that scientists say are damaging the Earth’s coral reefs. Passed by state legislators on May 1 [2018], the bill targets two chemicals, oxybenzone and octinoxate, which are found in thousands of sunscreens and other skincare products. Studies published over the past 10 years have found that these UV-filtering chemicals–called benzophenones–are highly toxic to juvenile corals and other marine life and contribute to the fatal bleaching of coral reefs (along with global warming and runoff pollutants from land). (A 2008 study by European researchers estimated that 4,000 to 6,000 tons of sunblock accumulates in coral reefs every year.) Also, though both substances are FDA-approved for use in sunscreens, the nonprofit Environmental Working Group notes numerous studies linking oxybenzone to hormone disruption and cell damage that may lead to skin cancer. In its 2018 annual sunscreen guide, the EWG found oxybenzone in two-thirds of the 650 products it reviewed.

The Hawaii ban won’t take effect until January 2021, but it’s already causing a wave of disruption that’s affecting sunscreen manufacturers, retailers, and the medical community.

For starters, several other municipalities have already or could soon join Hawaii’s effort. In May [2018], the Caribbean island of Bonaire announced a ban on chemicals sunscreens, and nonprofits such as the Sierra Club and Surfrider Foundation, along with dive industry and certain resort groups, are urging legislation to stop sunscreen pollution in California, Colorado, Florida, and the U.S. Virgin Islands. Marine nature reserves in Mexico already prohibit oxybenzone-containing sunscreens, and the U.S. National Park Service website for South Florida, Hawaii, U.S. Virgin Islands, and American Samoa recommends the use of “reef safe” sunscreens, which use natural mineral ingredients–zinc oxide or titanium oxide–to protect skin.

Makers of “eco,” “organic,” and “natural” sunscreens that already meet the new standards are seizing on the news from Hawaii to boost their visibility among the islands’ tourists–and to expand their footprint on the shelves of mainland retailers. This past spring, for example, Miami-based Raw Elements partnered with Hawaiian Airlines, Honolulu’s Waikiki Aquarium, the Aqua-Aston hotel group (Hawaii’s largest), and the Sheraton Maui Resort & Spa to get samples of its reef-safe zinc-oxide-based sunscreens to their guests. “These partnerships have had a tremendous impact raising awareness about this issue,” says founder and CEO Brian Guadagno, who notes that inquiries and sales have increased this year.

As Bluestein notes there are some concerns about this and other potential bans,

“Eliminating the use of sunscreen ingredients considered to be safe and effective by the FDA with a long history of use not only restricts consumer choice, but is also at odds with skin cancer prevention efforts […],” says Bayer, owner of the Coppertone brand, in a statement to Fast Company. Bayer disputes the validity of studies used to support the ban, which were published by scientists from U.S. National Oceanic & Atmospheric Administration, the nonprofit Haereticus Environmental Laboratory, Tel Aviv University, the University of Hawaii, and elsewhere. “Oxybenzone in sunscreen has not been scientifically proven to have an effect on the environment. We take this issue seriously and, along with the industry, have supported additional research to confirm that there is no effect.”

Johnson & Johnson, which markets Neutrogena sunscreens, is taking a similar stance, worrying that “the recent efforts in Hawaii to ban sunscreens that contain oxybenzone may actually adversely affect public health,” according to a company spokesperson. “Science shows that sunscreens are a key factor in preventing skin cancer, and our scientific assessment of the lab studies done to date in Hawaii show the methods were questionable and the data insufficient to draw factual conclusions about any impact on coral reefs.”

Terrified (and rightly so) about anything scaring people away from using sunblock, The American Academy of Dermatology, also opposes Hawaii’s ban. Suzanne M. Olbricht, president of the AADA, has issued a statement that the organization “is concerned that the public’s risk of developing skin cancer could increase due to potential new restrictions in Hawaii that impact access to sunscreens with ingredients necessary for broad-spectrum protection, as well as the potential stigma around sunscreen use that could develop as a result of these restrictions.”

The fact is that there are currently a large number of widely available reef-safe products on the market that provide “full spectrum” protection up to SPF50–meaning they protect against both UVB rays that cause sunburns as well as UVA radiation, which causes deeper skin damage. SPFs higher than 50 are largely a marketing gimmick, say advocates of chemical-free products: According to the Environmental Working Group, properly applied SPF 50 sunscreen blocks 98% of UVB rays; SPF 100 blocks 99%. And a sunscreen lotion’s SPF rating has little to do with its ability to shield skin from UVA rays.

I notice neither Bayer nor Johnson & Johnson nor the American Academy of Dermatology make mention of oxybenzone’s possible role as a hormone disruptor.

Given the importance that coral reefs have to the environment we all share, I’m inclined to support the oxybenzone ban based on that alone. Of course, it’s conceivable that metallic nanoparticles may also have a deleterious effect on coral reefs as their use increases. It’s to be hoped that’s not the case but if it is, then I’ll make my decisions accordingly and hope we have a viable alternative.

As for your sunscreen questions and needs, the Environment Working Group (EWG) has extensive information including a product guide on this page (scroll down to EWG’s Sunscreen Guide) and a discussion of ‘high’ SPF numbers I found useful for my decision-making.

Physics and coral skeletons at the nanoscale

Given that today, Oct. 31, 2013, is Hallowe’en, it seems thematically appropriate to be talking about skeletons, in this case, coral skieleton. An Oct. 29, 2013, news item on Nanowerk profiles the research (Note: A link has been removed),

An international team of scientists, led by physicists from the University of York, has shed important new light on coral skeleton formation.

Their investigations (“Microstructural evolution and nanoscale crystallography in scleractinian coral spherulites”), carried out at the nanoscale, provide valuable new information for scientists and environmentalists working to protect and conserve coral from the threats of acidification and rising water temperatures.

The Oct. 29, 2013 University of York (UK) news release, which originated the news item, describes coral and what the scientists were looking for,

As corals grow, they produce limestone – calcium carbonate – skeletons which build up over time into vast reefs. The skeleton’s role is to help the coral’s upper living biofilm to move towards the light and nutrients.

Understanding the calcification mechanism by which these skeletons are formed is becoming increasingly important due to the potential impact of climate change on this process.

The scientists looked at the smallest building blocks that can be identified – a microstructure called spherulites – by making a thin cross-section less than 100 nanometres in thickness of a skeleton crystal. They then used Transmission Electron Microscopy (TEM) to analyse the crystals in minute detail.

The TEM micrographs revealed three distinct regions: randomly orientated granular, porous nanocrystals; partly oriented nanocrystals which were also granular and porous; and densely packed aligned large needle-like crystals.

These different regions could be directly correlated to times of the day – at sunset, granular and porous crystals are formed, but as night falls, the calcification process slows down and there is a switch to long aligned needles.

“It has been suspected for some time that the contrast bands seen in crystals in optical images were daily bands. Through our research we have been able to show what the crystals actually contain and the differences between day and night crystals.” [said corresponding author Renée van de Locht,]

I know coral is important but I didn’t know why (from the news release),

Corresponding author Renée van de Locht, a final-year PhD student with the Department of Physics at the University of York, says, “Coral plays a vital role in a variety of eco-systems and supports around 25 per cent of all marine species. In addition, it protects coastlines from wave erosion and plays a key role in the fisheries and tourism industries. However, the fundamental principles of coral’s skeleton formation are still not fully understood.

While the researchers are concerned about climate change and ocean acidification, there are other agendas being pursued as well (from the news release),

The York researchers are now turning their attention to looking directly at the effects of acidification. Their latest research is looking at five-day old coral larvae and compares a population from a normal seawater environment with another in an acidic environment.

The aim is to investigate the nanoscale impacts of the different environments at an early growth stage to assess how these could affect the whole colony and the bigger reef.

The coral research at York is also part of a much larger project looking at the hard and soft matter interface called the MIB – Interface between Materials and Biology – project. Nature has created materials that combine mineral (hard) and organic (soft) components in a way that provides properties that are extremely well suited to function – for example in bone, egg or mollusc shells. The collaborative project aims to develop a working understanding of how this control is worked out in natural systems, so that the same techniques can be used to develop new materials with specially tailored properties.

Here’s a citation for and a link to the published research paper,

Microstructural evolution and nanoscale crystallography in scleractinian coral spherulites by Renée van de Locht, Andreas Verch, Martin Saunders, Delphine Dissard, Tim Rixen, Aurélie Moya, and Roland Kröger. Journal of Structural Biology, Volume 183, Issue 1, July 2013, Pages 57–65 DOI:10.1016/j.jsb.2013.05.005

The paper is behind a paywall which includes a rental option, as well as, the option of paying for the paper outright. You can also try accessing the paper here at ResearchGate which requires that you register for a free account.