Interviewees:
Dr. Craig Downs, executive director Haereticus Environmental Laboratory
Dr. Miko Yamada, senior research fellow at Skin Research Center, University of York
Dr. Judith Sirokay, senior dermatologist at University Hospital Bonn
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Transcript:
Craig Downs: And I was distressed, and I was looking for Oreo cookies in the local supermarket, and it was just me and another scientist, and we were arguing with each other across the aisles.
And the cashier was a Rastafarian gentleman who got into the conversation and thought, “You know, man, you're so stupid. It's the tourists.”
We're like, “What do you mean, it's the tourists?” He goes, “It's the tourist man. Go at five o’clock after all the tourists leave Trunk Bay. He says, as the sun is setting, he says, “The water is beautiful. It's on fire.” What are you talking about?
Well, we go there the next day and the gentleman was completely right. You see this iridescence when the sun is just right and that's what we saw, we saw this beautiful iridescence in the water, cause that day must have had three to 4,000 tourists in Trunk Bay. At that time, in 2005, most sunscreens were made of oil. They were oil-based components.
This is Living Planet. I’m Kathleen Schuster.
The man you just heard is Dr. Craig Downs. Back in 2005, he was part of a team that received federal funding to find out why different bays in Virgin Islands National Park were dying.
The moment they saw the oil shimmering in Trunk Bay, something clicked. You see, the oil was like a big flashing light pointing to lots and lots of sunscreen chemicals in the water.
Craig directs a non-profit called the Haeriticus Environmental Laboratory in Virginia. He’s also a forensic ecotoxicologist, a researcher who collects data on toxic substances in the environment, which can be used by government agencies or the courts.
It’s been nearly 20 years since that first discovery and today places, like Hawaii, have even banned some sunscreen chemicals – and this is, in part, thanks to Craig’s research. Which he says is far from over, because sunscreen’s sticky white footprint is being found in places you wouldn’t imagine. Luckily, as Craig sees it, this is a problem we can solve.
So, in this episode of Living Planet, we’re doing a deep dive on sunscreen. The environmental damage it’s caused so far. And what this problem means for human health.
Kathleen: So, in preparation for this interview, I asked several friends to send me pictures of the sunscreen that they use, and the back of the sunscreen, with the list of ingredients. But I'm going to pick one of these at random, and I'd like to read the list of ingredients and when I get to one that you would consider a threat or a danger to the environment. Could you say something?
Craig: Sure.
Kathleen: OK, here we go. I don't even know how to pronounce this: drometrizole trisiloxane.
Craig: The dose makes the poison, and so at high concentrations it could be considered a threat to the environment. It's an endocrine disruptor.
Kathleen: OK, that's the first one on this list, let's go to the second one. Bemotrizinol.
Craig: Really? So that is a UV filter, and this must be a European sunscreen because that chemical is not allowed in the United States by the US Food and Drug Administration. There's not a lot of science on it and we find it pervasive in the environment. It’s ubiquitous in the environment.
Kathleen: Well, this is a French sunscreen, just to be clear. So, you guessed correctly. Dare I go onto the third ingredient? Octisalate.
Craig: Octisalate is related to homosalate and it's a UVB absorber, and again there's not a lot of science on it. It is rather ubiquitous in the environment.
Kathleen: OK, this is getting very depressing very quickly. Let’s going to the fourth ingredient: octocrylene.
Craig: Octocrylene definitely poses a threat to the environment as well as potentially to people at high enough concentrations. It itself is an endocrine disruptor. It is an obesogen, so it causes endocrine disruption of your fat cells, your adipose cells. So, in some individuals it can make them more obese, in other species it might make them very skinny and not able to keep energy reserves.
Kathleen: So, of the ones that I've read to you, which ones do you consider the biggest threat based on the research you've done on corals?
Craig: Octocrylene, by far is probably the largest threat. We detect in the fish that you eat. We detected in certain vegetables that are grown using sewage amendments and it's used in so many products all over the world, it's hard not to find it along some coastline or it's or in some river or some lake.
And it's at really high concentrations, concentrations high enough to induce toxicity in a wide variety of organisms, from plants, all the way to coral.
Those ingredients that Craig says pose an environmental risk are all UV filters. In other words, the chemicals that protect our skin cells from DNA damage.
UV filters absorb the sun’s radiation, which is great for us humans who want to avoid premature aging or skin cancer, especially those of us with lighter skin.
But Craig Downs and his team found that a UV filter, called oxybenzone had the opposite effect on baby corals. Oxybenzone is derived from a chemical with toxic traits called benzophenone. Both of these chemicals can disrupt hormones.
Craig: So this is the, the juvenile or baby form of corals. They're sessile, meaning they float in the ocean. They're at the surface of the ocean, which is where all the sunscreen is at. And so, they're being literally washed in in, in sunscreen when coral spawn.
Craig says oxybenzone causes the baby coral to encase themselves in their own skeletons. Essentially a stone coffin of their own making.
Craig: And we're seeing coral declines all over the world. And part of that decline is from a lack of coral recruitment, juvenile recruitments back into these reefs. And it was this discovery in 2015 that allowed us to make the hypothesis that it could be that many of these coral reefs that are near shore near lots of tourist places, the reason why they're disappearing is because they're not seeing juveniles, you know, baby corals recruiting year after year and we actually came up with the term for these reefs that don't see these juvenile corals. We call them coral zombies, because they're dead.
If you don't have a future generation coming in. That reef sooner or later is going to perish and with coral reefs it takes 10 to 20 years for these reefs to perish if they don't see this new recruitment.
By Craig’s estimation, a beach that sees mass tourism, let’s say 5,000 visitors a day, would translate to about 360 kilos of sunscreen being used per day. That’s assuming people are applying it every two hours.
So, even if a chemical like oxybenzone only makes up 3% of the sunscreen, that’s still 10 kilos of oxybenzone per day ending up in the beach’s ecosystem.
Craig: We've also discovered that the sunscreen spray or sunscreens in the water, when they are at the beach and are in what are called the swash zone, the swash zone is where all the waves occur along the beach, that that aerosolizes the sunscreens already in that water and carries them down the beach further inland.
Craig also points out that the chemical oxybenzone is derived from benzophenone – a compound that in some forms can be used as a weed killer.
Craig: And those chemicals land on the plants that are growing on the dunes and those sand dunes are really important because they prevent coastal erosion. And those plants preserve the sand dunes. So, if you're killing the plants on the sand dunes, which is what we see the world over you're gonna lose those sand dunes. And next time the storm comes, you're going to lose that coastline.
And so that's one of the things we discovered is that, wow, all these tourists using all these sunscreens, some of them break down into patented herbicides are hitting these plants and are killing these plants. And again, the easy solution is to still enjoy the beach but not use products that contain some of these threatening or dangerous chemicals.
Craig’s research was one of the driving forces behind Hawaii’s ban on oxybenzone, and another UV filter called octinoxate in 2021.
But remember that other chemical on the back of the sunscreen bottle? Octocrylene? The one Craig said posed the greatest danger to the environment?
Craig and researchers from the Sorbonne University, came out with a study in 2021 that showed that octocrylene also breaks down into benzophenone.
One solution to this environmental problem would be to ditch chemical sunscreen. Afterall, UV filters are a problem for marine life in general, not just coral. They’ve been detected most recently in dolphins off the coast of Brazil, and they’ve also been found to alter the development of embryos from shrimp and zebra fish.
And then there’s the question of our health -- studies in Brazil and Spain have also detected UV filters in tap water, albeit at low levels.
So, an alternative would be to use physical sunscreen, which relies on zinc oxide and titanium dioxide to reflect and scatter the sun’s rays.
But even then, you’re still going to have to read the back of the bottle carefully.
Craig: You know, there's a new chemical that just showed up in zinc oxide sunscreen called ethylhexyl methoxycrylene.
And you know, you would think, hey, you know, I'm buying a mineral sunscreen. It just has zinc in it. This is not in the active ingredients. This is what we call a shell game chemical.
This is a chemical put in by the sunscreen company. They want to boost their SPF. This is a UV filter. But it's not recognized by the FDA or by EU reach as a UV filter. Unfortunately, the thing breaks down in the bottle, just like octocrylene, cause it's related to octocrylene. It breaks down into a benzophenone.
Kathleen: Tell me. Sorry. Hold on just a second. I cannot not look at this list. OK, tell me one more time what that was called.
Craig: It’s called ethylhexl and then the second word is methoxycrylene.
Kathleen: Because I have so this is the one that I use that's approved for kids: ethylhexyl oxyphenol methoxyphenyl triazine.
Craig: I personally I would not put those products on a on a child.
Kathleen: OK.
Craig: That's just me. The reason why the US has only two safe and effective sunscreen ingredients and 12 that are allowed to be used, but they're not recognized as safe and effective is because industry hasn't provided any data.
And what are those two ingredients, you ask? Zinc oxide and titanium dioxide – the main ingredients in mineral sunscreen.
If your head is spinning at this point, don’t worry, you’re not alone. Sunscreen safety has become a contentious issue. And not just when it comes to the environment. There are more and more questions about how it might be affecting human health.
The real kicker is that even if you don’t go anywhere near a beach, but you wear sunscreen, those ingredients are definitely ending up in the wastewater, either by way of the shower drain or through our urine. And treatment facilities generally can’t completely remove UV filters.
So now the big question – what are the potential risks and do they outweigh the benefits of protecting ourselves from skin cancer?
Miko: My name is Miko Yamada. I'm a senior research fellow at Skin Research Centre Hall, York Medical School, University of York in the UK.
Dr. Miko Yamada started working in dermatological research in Australia before moving with part of the team to the UK several years ago for a cutting-edge project.
The team is developing minimally invasive techniques involving imaging and AI to find out more about what happens to sunscreen once it’s applied to the skin, which has three layers…
Miko: ... top layer, middle layer and bottom layer where those blood vessels and kind of that's you don't want that skin product to be go to 3rd layers.
She says there are quite a few shortcomings to more commonly used methods, which include things like testing on skin cells in a petri dish, or even, sorry to get a bit graphic here, using human skin removed during abdominal reduction surgery. When it comes to testing on people, that’s much harder ethically. And going the biopsy route isn’t really feasible for long-term testing either.
But so far, the minimally invasive technology she’s helping develop has confirmed that chemical sunscreens generally don’t enter the bloodstream.
Miko: We're showing that using microbiopsy that chemical sunscreen definitely stop in second layer of the skin. And when it comes to physical sunscreen, they really stay at the top. So, we're showing that on the paper in 2020 that it’s safe.
There’s also been concern about whether physical sunscreens are less safe because of their nanoparticles. But she says, that’s actually not the case. For humans, at least.
Miko: Skin is not flat. They got bumps and things like that. So, what the smaller particles get, it's actually aggregates when aggregates. It's kind of stuck on the surface of the skin. And as you say, skin that the hair follicle furrows and we're showing it from the imaging point of view, it's actually stuck on the surface of the skin.
So, there’s a big caveat here and I bet it’s one many of you out there don’t follow. I certainly am guilty of it: and that’s failing to wash off sunscreen quickly enough.
Miko says, the longer it’s on your skin, the more likely it’ll be absorbed beyond what’s considered safe. And that limit is about 2 hours – the same point at which you’re supposed to reapply it. And here again, I’m as guilty as heck.
Miko: I would say two hours by the time 2 hours, there's no point having that old chemical sunscreen because it's being used on the top of it. You have sweat, you are warm and everything is basically enhancing to absorb even more inside the skin. So yeah, I would say two hours.
I wanted to get another point of view on sun protection from an expert on skin cancer at the University Hospital Bonn. Her name is Dr.Judith Sirokay.
Especially because here in northern Europe, skin cancer rates are on the rise.
Dr. Sirokay has been seeing more and more patients, especially men over the age of 65, who are coming in with skin cancer.
Sirokay: We see that incidences in men, in older men for squamous cell carcinoma, for baloma [ed. basal cell] and for melanoma are rising, so that may be due to occupational hazards when your when your outdoor worker like in construction or in farming or anything and you did not protect yourself well.
So right now the awareness is higher also for the for the people working. But 50 years ago, I guess you worked without sun sunscreen, without protection. And now, well, you're paying the toll.
A recent German study found that between 2007 and 2015, rates of skin cancer rose by nearly 4% in men and 5% in women. Here and around the world, these rates are rising especially among older Caucasians. One reason for the jump in numbers is because more people are getting screened. Dr. Sirokay says th e other is likely due to lack of skin protection over many years.
Considering Europe is heating up faster than any other continent, sun protection awareness has become vital. Dr Sirokay says children and teens are especially vulnerable – and here again, parents are worried about sun safety.
Sirokay: So if one would ask me so do you apply sunscreen? I would say, yes, I would. I would look at the ingredients and there are some ingredients that are causing harm to the environment. So, I would not use these ones.
But I guess when I have to weigh the problematics I would pose UV light as the main causing agent of skin cancer of photo aging and I would recommend sunscreen because we don't have enough evidence that certain components of sunscreens are really causing skin cancer, so we don't know this for sure. I would I would, I would not apply all sunscreens.
There are some known hazards, but we don't have a real threshold to say at this threshold it's dangerous. So I think there has to be more research on this.
And as someone who sees skin cancer on a daily basis, Dr. Sirokay says even though the treatment options are very good these days, some cases still go untreated – which can ultimately be devastating for patients.
Sirokay: If you have a wound that does not heal in your face and it gets larger, or even the tumor for example in your face, it may destroy bones, the nose, the lips and if you if you operate on it will really disable you for everyday life and even disfigure yourself.
So, I can look in the future and there are powerful agents targeting the immune system and the interaction immune system and cancer that may cause regression of the tumor and in some patients it may even go away. But I don't think you'll be unscarred by it. So, I think you'll see it for the rest of your life. Or it may even kill you. So, if you don't really treat it.
Kathleen: Have you ever seen a case that as dramatic as you just described?
Sirokay: So, we're as a University Hospital here and we see it on a regular basis.
So with squamous cell carcinoma and and with Melanoma as well. But we're a specialized hospital, but yes, we do.
So, where does this leave us? There’s a consensus that certain ingredients in sunscreen cause environmental damage, especially to marine life.
There’s also a consensus that not all ingredients in sunscreen are good for humans, and that more research is needed. But also among dermatologists that sunscreen is really important for preventing skin cancer.
That being said, they also emphasize that sunscreen really shouldn’t be the only way you’re protecting your skin.
And Craig Downs agrees.
Craig: So let me say you need to protect yourself from the sun. That's really important. But there are many effective ways of doing that. And one of the ways is to wear what we say if you're at the beach wearing UPF sunwear at least a shirt with sleeves. Wearing a UPF sun shirt reduces the amount of sunscreen a person will use at the beach by 50% more. That is a big, big deal. So just by wearing a sun shirt and then using sunscreen on the rest of your body, we 've been able to reduce now the sunscreen contamination from, let's say, 1,000 to 5,000 swimmers. So that's great.
Even better news is that sunscreen levels in the environment can actually go down. Craig and other researchers recently published a study that measured the levels of sunscreen ingredients in one of Hawaii’s National Parks and another National Park in North Carolina during lockdown.
Craig: And what we found, which was kind of obvious, you know, you would think to be obvious, but you'd really need to collect the data, was that sunscreen levels were hardly detectable at these locations. But after the anthropause and a year later, once you know the summer later, once everybody started showing up again and we started seeing 300 to 3,000 people on the beach, sunscreen levels went sky high.
And what was also kind of interesting is during that anthropause there are numerous reports in the news where life or nature came back to many of these locations. For example, dolphins swimming in the canals of Venice in Italy. Brazilians said that hey, ghost crabs on the beaches were coming back if, if you are a Pacific Islander like me and were used to where places where tourists never showed up yet when we were kids, we would see ghost crab holes all over the place on the beaches. And they're so bad that your mom or dad would trip on them and sprain their big toe. They were a hazard. Nowadays, when you go to Hawaii in many other locations in Brazil, in Spain, you can't find ghost crabs. And we've got some pretty good data showing that the chemicals in sunscreens can it might be contributing to the death of the suppression of those populations of ghost crabs on the beaches. That’s really unfortunate because they’re a main food source for a lot endangered species of migratory birds.
Really, the list goes on and on once you start looking at the knock-on effects of sunscreen. Not just in the ecosystem, but also when it comes to climate resilience.
Think of the sand dunes that protect from storm surges. Or how coral reefs are important for the underwater ecosystem, protecting the coastline, and, of course, for tourism.
But sunscreen might be speeding up coral bleaching. Craig says corals start to turn white and weaken when waters hit 30.5 degrees for two weeks. For US listeners that’s about 87 degrees Fahrenheit.
But he and his team have found that exposure to oxybenzone causes corals to start bleaching at 27 degrees (or 80 degrees Fahrenheit). They’re still trying to establish why that is.
Considering the sunscreen market is booming and is already worth well over $10 billion and growing fast, it’s worth taking a closer look at the back of the bottle.
While producing this episode of Living Planet, there were a few sun safety tips our experts wanted to pass along.
First: don’t skip the sunscreen if you’re afraid it’ll keep you from getting your daily Vitamin D. You’ll still get it even with sunscreen on.
And when it comes to choosing environmentally-safe sunscreen, avoid chemicals like oxybenzone and octocrylene. When in doubt, your best bet right now is mineral sunscreen (or physical sunscreen) with zinc oxide and titanium dioxide. Here Craig recommends looking for ones that don’t contain nano particles.
Second, don’t forget to wear a hat and light and airy clothing that protects your skin whenever you can. UPF clothing is also great option at the beach. And this cuts down on needing nearly as much sunscreen.
If you’re going to be outdoors for a long time, try to avoid the sun at peak hours when UV radiation is highest. Generally late morning to late afternoon.
Also, try to sit in the shade whenever you can. And as Dr. Miko Yamada pointed out, two hours in the sun is a good rule of thumb – that goes for when to wash off and reapply sunscreen and also for just taking a break.
And finally, no matter your skin type, talk to your doctor about a skin cancer screening. It might just save your life.
This episode was written and produced by me, Kathleen Schuster, and edited by Neil King. Our sound engineer was Thomas Schmidt.
Our sound engineers were Thomas Schmitt and Jürgen Kuhn.
Thanks for listening. If you're enjoying Living Planet, we'd love it if you took a moment to give it a rating and review on Apple Podcasts or wherever you listen to podcasts.
Living Planet is produced by DW in Bonn, Germany.