As someone who hits the beaches in Kauai fairly often, I've migrated to just using a rash guard and hat for sun protection. My lower legs for whatever reason don't get burned. I feel much better about not putting whatever is in sunscreen all over my body. Sometimes I'll throw some zinc oxide on my nose, but mostly just for a kitschy throwback.
The FDA considers zinc oxide and titanium dioxide to be the only safe sunscreens in existence. It allows a whitelist of about 10 chemicals to be sold as sunscreen. Everything else "doesn't have enough data" but there is evidence that many of the chemicals on the FDA sunscreen whitelist are endocrine disruptors.
I appreciate that zinc oxide is a UVA blocker in addition to UVB. I always thought more SPF gave me more protection until I realized it does not measure UVA whatsoever.
Turns out that depending on where you live if you are outside before 9:30 am and after 3:30 pm you won't get sunburned because the UV index is less than 3-5 at those times
Windy has a new UV layer but I would trust a UV measuring device more. Just collect some sample readings over a few typical days to get a feel for the irradiation in your area so you can plan accordingly.
One of the most interesting sunscreen metrics is mentioned completely unceremoniously on the last page of the Final Order Monograph 2020.
It is sad that we don't have access to the critical wavelength value calculations described on the last page of Monograph M020. The critical wavelength is identified as the wavelength at which the integral of the spectral absorbance curve reaches 90 percent of the integral over the UV spectrum from 290 to 400 nm. A mean critical wavelength of 370 nm or greater is classified as broad spectrum protection.
Sunscreen users could benefit from understanding the UV blocking performance of each sunscreen on the market.
Reference:
U.S. Food and Drug Administration
Final Administrative Order (OTC000006)
Over-the-Counter Monograph M020:
Sunscreen Drug Products for Over-the-Counter Human Use
(Posted September 24, 2021)
BadgerBalm has probably the most environmentally friendly sunscreen. It can leave a white cast on some people so there is that issue. But if your at the beach regularly give them a look. Using UPF clothing and a bigger hat really make a difference too. I burn far to easy to not use some level of sunscreen.
It sounds like there's a solution in not discharging directly from the beach showers. I wonder if it might be feasible to collect that water somehow and use it as greywater elsewhere: watering plants, for instance.
Most people who use beach showers have come out of the ocean. Swimming seems like the primary point of transfer of sunscreen from body -> ocean, not the shower.
It varies by where you are on the island, and I don't mean this as an excuse for wastefulness, but Hawaii gets enough rain that it wouldn't be worth bothering with.
Last August my wife and I visited Maui, bringing a physical sunscreen (Zinc oxide based, I think). My wife put on so much that her face almost looked like a kabuki actor, and I looked only a little better. On beaches we'd see all those people in bikinis, apparently completely free of sunscreen whiteness.
"How come they aren't getting sunburned?" I wondered.
"They're using chemical sunscreens," was my wife's answer.
And that's often right next to a signpost telling people how those chemicals are killing corals.
Only a limited subset of the available chemical filters are suspected of having an effect on coral. Further, even for those filters that are suspected, I have read that the science is inconclusive.
I personally am skeptical of the idea that sunscreens are actually responsible for marine ecosystem changes, rather than climate change or other large forces. The majority of a chemical sunscreen formula is inert base. And we’re talking about thin films of sunscreen diluting into a vast body of water. Further, most people at the beach are using water resistant sunscreen, further reducing the potential for harm.
Sunscreens are really valuable technology. They prevent skin cancers and sun damage, and I think policy should err on the side of encouraging their use.
I further think that reactive, feel-good measures like banning straws and demonizing sunscreen do much more harm than good, because they cause fatigue and apathy about environmental issues and do little to solve them.
This article has come up before and might interest you. [1]
tl;dr: exposure to sunlight without sunscreen has benefits for cardiovascular health - and the kinds of cancer you get from direct exposure to sunlight on a regular basis (basal cell and squamous cell carcinomas) are almost never fatal. The benefits to CV health significantly outweigh the increased risk of these carcinomas.
Melanomas only account for 1-3% of skin cancers and are less likely in outdoor workers and tanned people than they are in indoor workers.
> “The risk factor for melanoma appears to be intermittent sunshine and sunburn, especially when you’re young,” says Weller. “But there’s evidence that long-term sun exposure associates with less melanoma.”
Makes sense, humans probably wouldn't have made it this far without going outside.
Resistance to sunburn increases exponentially with regular exposure, and without it falls back to your genetic base level. That's not hyperbole, UV treatment in medical facilities have to start with seconds of treatment which is increased by a percentage each time until you get to effective levels.
That's not to recommend that you try doing that yourself, just a weird fact I learned. its hard to calibrate sun exposure. But theoretically starting from very sensitive skin isn't a barrier.
And UV damage is cumulative as well. Even if you ignore melanoma, there are several non-cancerous or pre-cancerous skin conditions from sun exposure.
If you go to Asia where most women avoid any sun exposure at all (up to wearing masks and gloves) you’ll note there skin looks amazing even into their 50’s.
And the few minutes of exposure you get each day is usually enough to provide vitamin D. I think it’s like 12 min of upper body exposure in moderately intense sunlight is enough.
The point the article makes is that it's not just about vitamin D but also nitric oxide synthesized which lower blood pressure and improve CV health in excess of whatever risk you accrue from the sun exposure.
It's important to consider of course that different races age differently. Is it masks and gloves, or is it being of the local ethnicity? Not getting any sun at all is really bad, after all, since as the article shows, vitamin D supplementation is quite ineffective.
> If you go to Asia where most women avoid any sun exposure at all (up to wearing masks and gloves) you’ll note there skin looks amazing even into their 50’s.
I kind of resent the idea that this is model to strive for. Ok, you look somewhat better, but you also pay price of constantly limiting activities and having to be careful what you do ... all the time.
I didn’t read it being cited here so much as a model to strive for, but rather as strong evidence that there is UV damage to skin even at a sub-cancerous level.
Exactly. I don’t avoid the sun to that extent, but it’s pretty obvious that every strong sun exposure is a little bit more damage each time.
There was an interesting paper that show a woman who applied a sun protecting lotion to her face everyday for the last 30 years of her life.
But she didn’t apply it to her neck. The difference is very stark at 70 years old. The skin on her face was wrinkled but her neck look absolutely worse in terms of age and skin damage.
It avoiding that "damage" worth the daily effort described above? Does that damage consists of anything more then just "her skin is slightly less flat in the old age"?
Also, you don’t have to go to those extreme lengths to prevent the bulk of photoaging. Just staying out of the sun during peak UV hours and consistently using sunscreen on the areas that get the most exposure (face, neck, hands) will get you very far.
Vitamin D production is highly dependent on time of day and latitude. At latitudes closer to the poles, even extended sun exposure might not stimulate much vitamin D. You can find online calculators which show this for your location.
Again basal cell and squamous cell carcinomas have roughly a 100% 5-year survival rate - so much so it's not really been calculated. But the risk of melanoma, which is the bad one (and only accounts for 1-3% of skin cancers), goes down with more exposure to the sun. And as the article says, the benefits to CV health and reduction in melanoma risk outweigh the risk associated with these very low-risk cancers.
That article isn't strictly wrong to say that exposure to sunlight is linked with melanoma, but it's linked to childhood sunburns and intermittent sunshine/sunburn. Sunburns are bad, sun is good.
> And perplexingly, outdoor workers have half the melanoma rate of indoor workers. Tanned people have lower rates in general.
I think it's also fair to say that exposure to the sun doesn't cause premature aging so much as not being exposed to the sun makes you look younger than you would otherwise - but of course that only helps if you're alive. Direct sun exposure reduces all-cause mortality. [1]
Interesting article, but note that moderate sun exposure has a lower mortality than either "no" or "lots of" sun exposure.
Which is not surprising considering the need for sun exposure for things like vitamin D.
But I'm not sure mortality is the best measure? Maybe quality of life? Getting surgery to remove a basal cell carcinoma and having failed skin grafts (happened to my grandmother) seems like a heavy burden to cost of life not captured in mortality.
There's no point in talking about sunscreen without reference to skin type. You're probably a Type 1, which doesn't tan in any significant way.
Anyone in the 2 and 3 range can build significant sun tolerance by being careful, 4 and 5s don't generally need sunscreen. Jury is out on skin cancer, Bantu people in Africa don't all die of melanoma, so clearly melanin is doing a lot of work here.
Just use reef-safe sunscreen... and help- protect what makes Hawaii & the tropics amazing https://www.popsci.com/gear/best-reef-safe-sunscreens/ This has been well known in the dive community for a while, the NEWs here is that beach-bodies need to use reef-safe sunscreen too.
I personally am skeptical of the idea that sunscreens are actually responsible for marine ecosystem changes, rather than climate change or other large forces
I would've said so, too, before my GF got into the reef tank hobby. Corals are ridiculously sensitive to pretty much everything. Light, chemicals, nutrients, water flow, diurnal rhythms, you name it. It's fairly believable that something in the low parts per billion might affect them adversely, particularly organisms that are already stressed.
We lost several hundred dollars worth of coral and fish in our reef aquarium when a house guest, after being told explicitly not to, used body spray stuffs two or three rooms over in a large house. These things are _sensitive_.
It has happened before when our kids were younger and discovered perfume. These things don't mix well with reef aquariums. The rule stands at our house: no spraying anything that you are not 100% sure is reef-safe safe to spray.
I think instead of bending the knee to the idea of fatigue, it’s more important to accept that humans really are screwing up things on a massive scale faster than ever. Plastic straws, chemical sunscreens, gasoline, etc are all very recent inventions. It’s not unreasonable to look at massive unprecedented changes in the world and conclude that some of these things that came into widespread existence within recents decades is also causing massive destruction that only began in recent decades.
Completely disagree. Fatigue isn’t just an “idea,” it’s an unavoidable consequence of repeated exposure to a stimulus.
The political will to solve problems is a finite resource. Squandering it on trivial crusades is, IMO, one of the most wasteful and harmful decisions that could be made.
> The political will to solve problems is a finite resource.
Gee, humanity had better act fast to protect that precious finite resource. What would our children and grandchildren think if we squandered our political will to solve problems?
Less finite than earth’s natural resources amidst the unprecedented rapid deterioration and destruction of basically everything on earth sans colossal asteroid strikes?
Trivial to some upper class person in an air conditioned home who doesn’t want to think about bad things and who’ll survive no matter what is certainly not trivial to billions increasingly struggling to survive with no way to escape to greener pastures.
The upper classes are more likely to support environmental policies, so this is a pretty asinine comment. And it's these same upper classes that are pushing for frivolous as opposed to substantive policies (plastic straws, anti-nuclear, etc).
But is there anything functionally wrong with zinc oxide sunscreen? If not, why is it not available as the default option with chemical sunscreens available for those who want to go out of their way to not look pale?
That’s a good point. I think tolerability is the only drawback, otherwise zinc is functionally superior because it doesn’t get depleted in the way that chemical filters do. It does tend to be a lot heavier and greasier, though, and I’d say most people aren’t okay with the white/blue cast if they’re not at the beach. So chemical filters have an important role to play in terms of making sunscreen something that people can use consistently.
I am confused. the situation is exactly as you describe, modulo the word "default": zinc oxide sunscreens are available, chemical sunscreens are also available. And I'm not sure what "default" means in this context.
Anyway, if you spend a lot of time in the sun or at the beach the functional problem with zinc oxide is pretty clear: it's harder to spread and put on. This might not seem like an issue but if you spend a lot of time dealing with it, the annoyance adds up.
Chemical sunscreens are absolutely dwarfed in terms of magnitude to oil, farm run-off and mining and industry damage/chemicals, at least here in Queensland.
As a tourist, I buy it there. That way I know it's reef-safe without having to look at ingredients, and the few dollars spent vs. carrying a bottle through an airport is well worth it.
Many of the dive boats and hotels will offer sunscreen out of a bulk pump, so depending on what you do on the islands, you probably don't need much on your own - just a small tube for your group will do.
You're not technically allowed to bring the other stuff onto the islands, though in my experience they don't check, I flew into Maui from Japan one time and brought sunscreen (as you might imagine the ingredients are better across the board, including for reefs) and this wasn't checked at the agriculture scanner.
Point is, the regulations to keep those ingredients out of the reefs have been mostly successful.
A lot of locals just aren't out long enough to worry about it. When you live here you step out for an hour to hang out or get in the water. You're not there all day. Not sure if those were the people you were observing.
There are also reef-safe sunscreens that rub in much more clear.
I use zinc oxide. Brands vary, some suck IMO. The one I use doesn't show, provided that it's rubbed in really quickly, certainly within less than ten seconds. My wife prefers another brand, which also has the same time limit.
This means: Put a largish drop on a fingertip and rub it in, then repeat, and repeat, and repeat. If you squeeze out enough that you need to keep it in the hand instead of on a finger, it's going to show.
Wow what is with this comment and everyone lapping it up. I lived on Maui for a year. They sell reef safe sun screen in every store on the island. We didn't get sun burnt because A) you get used to it and B) because we had reef safe sunscreen that was good enough. But way to pat yourself on the back for no reason.
Also a lot of people on Maui actually live there and aren't even tourists.
There are now "transparent zinc oxide" sunscreens as well. See Dermstore[0] for EltaMD brand products. They grind the zinc oxide to much smaller particle sizes and it still blocks UV but doesnt reflect visible light nearly as much (like 99% reduction in white color).
I love it a lot. Zinc Oxide is great for being a true "sunblock" (rather than merely "sunscreen") of broad-spectrum UV (instead of just UVA or just UVB/UVC). Also doesn't interact with endocrine system like many of the chemical sunscreens.
> But even if a point source is established, Hoefner spots another hurdle: “Put yourself in the regulator’s shoes. You might look at this and go, these people have already been presumably swimming in the ocean, right?” Some of their sunscreen has already washed off into the water. “So should we really be so concerned that a little bit more is coming off an outdoor shower?”
> Downs has heard that argument before. “One swimmer, one shower, does it pose a threat? But 500 swimmers and more than 500 showers?” The difference, he says, is all in the concentrations.
> Cláudia Mieiro, a marine biologist at the University of Aveiro in Portugal who was not involved in Downs’ study, remarked on the high concentrations of sunscreen chemicals found in the sand near the showers. The sand, she said, appears to be acting like a sink for these compounds.
I don't see how this changes the argument. x% improvement on the issue of sunscreen in the ocean can be made by removing the shower, where x is probably small.
If I understand the article, combined with my paltry understanding of the law, the argument is the shower should be treated as a point source, which is covered under certain existing legislation.
Bathing is not a point source, so is covered by different legislation.
Point-sources can have higher concentrations in a small area, like the sand near the showers. These need to be addressed even if the non-point sources are also an issue.
> > Some of their sunscreen has already washed off into the water.
Yes and you can't change that, since there's already a ban.
> > Cláudia Mieiro, a marine biologist at the University of Aveiro in Portugal who was not involved in Downs’ study, remarked on the high concentrations of sunscreen chemicals found in the sand near the showers. The sand, she said, appears to be acting like a sink for these compounds.
Isn't that a good thing?
If you care about corals and marine life, and if you know that some people will not use the ideal sunscreen, you should prefer that sunscreen to be in the sand (where UV photodegradation may clean it out), rather than in the ocean: people going back into the ocean, or taking a shower at home (with the waste water then going... into the ocean) seems far worse.
So a ban + allowing showers so that the uncaught sunscreens ends up in the sand seems like the best possible outcome.
The two paragraphs after what I quoted address that, at least in passing.
> where UV photodegradation may clean it out
"May"?
The point is with the current system "Risk assessments for both sand and water samples at a majority of the sampling sites had a Risk Quotient > 1, indicating that these chemicals could pose a serious threat to beach zones and coral reef habitats."
The measured evidence is "Beach sands that are directly in the plume discharge of beach showers on three of the islands of Hawaii (Maui, Oahu, Hawai’i) were found to be contaminated with a wide array of petrochemical-based UV-filters that are found in sunscreens." (both quotes from https://www.sciencedirect.com/science/article/abs/pii/S03043... )
It's not staying in the sand. It's not photodegrading fast enough.
For bonus points, it's not like photodegradation doesn't have it own issues. As one of the linked-to documents points out, at https://link.springer.com/article/10.1007/s00244-015-0227-7 , "Benzophenones, including BP-3, are documented mutagens that increase the rate of damage to DNA, especially when exposed to sunlight."
79 comments
[ 2.1 ms ] story [ 143 ms ] threadI appreciate that zinc oxide is a UVA blocker in addition to UVB. I always thought more SPF gave me more protection until I realized it does not measure UVA whatsoever.
Turns out that depending on where you live if you are outside before 9:30 am and after 3:30 pm you won't get sunburned because the UV index is less than 3-5 at those times
Windy has a new UV layer but I would trust a UV measuring device more. Just collect some sample readings over a few typical days to get a feel for the irradiation in your area so you can plan accordingly.
It is sad that we don't have access to the critical wavelength value calculations described on the last page of Monograph M020. The critical wavelength is identified as the wavelength at which the integral of the spectral absorbance curve reaches 90 percent of the integral over the UV spectrum from 290 to 400 nm. A mean critical wavelength of 370 nm or greater is classified as broad spectrum protection.
Sunscreen users could benefit from understanding the UV blocking performance of each sunscreen on the market.
Reference:
U.S. Food and Drug Administration Final Administrative Order (OTC000006) Over-the-Counter Monograph M020: Sunscreen Drug Products for Over-the-Counter Human Use (Posted September 24, 2021)
https://www.fda.gov/drugs/understanding-over-counter-medicin...
"How come they aren't getting sunburned?" I wondered.
"They're using chemical sunscreens," was my wife's answer.
And that's often right next to a signpost telling people how those chemicals are killing corals.
This is why we can't have nice things.
https://www.theatlantic.com/technology/archive/2022/07/us-su...
Previous discussion on HN: https://news.ycombinator.com/item?id=31954294
I personally am skeptical of the idea that sunscreens are actually responsible for marine ecosystem changes, rather than climate change or other large forces. The majority of a chemical sunscreen formula is inert base. And we’re talking about thin films of sunscreen diluting into a vast body of water. Further, most people at the beach are using water resistant sunscreen, further reducing the potential for harm.
Sunscreens are really valuable technology. They prevent skin cancers and sun damage, and I think policy should err on the side of encouraging their use.
I further think that reactive, feel-good measures like banning straws and demonizing sunscreen do much more harm than good, because they cause fatigue and apathy about environmental issues and do little to solve them.
tl;dr: exposure to sunlight without sunscreen has benefits for cardiovascular health - and the kinds of cancer you get from direct exposure to sunlight on a regular basis (basal cell and squamous cell carcinomas) are almost never fatal. The benefits to CV health significantly outweigh the increased risk of these carcinomas.
Melanomas only account for 1-3% of skin cancers and are less likely in outdoor workers and tanned people than they are in indoor workers.
> “The risk factor for melanoma appears to be intermittent sunshine and sunburn, especially when you’re young,” says Weller. “But there’s evidence that long-term sun exposure associates with less melanoma.”
Makes sense, humans probably wouldn't have made it this far without going outside.
[1] https://www.outsideonline.com/health/wellness/sunscreen-sun-...
That's not to recommend that you try doing that yourself, just a weird fact I learned. its hard to calibrate sun exposure. But theoretically starting from very sensitive skin isn't a barrier.
If you go to Asia where most women avoid any sun exposure at all (up to wearing masks and gloves) you’ll note there skin looks amazing even into their 50’s.
And the few minutes of exposure you get each day is usually enough to provide vitamin D. I think it’s like 12 min of upper body exposure in moderately intense sunlight is enough.
It's important to consider of course that different races age differently. Is it masks and gloves, or is it being of the local ethnicity? Not getting any sun at all is really bad, after all, since as the article shows, vitamin D supplementation is quite ineffective.
I kind of resent the idea that this is model to strive for. Ok, you look somewhat better, but you also pay price of constantly limiting activities and having to be careful what you do ... all the time.
There was an interesting paper that show a woman who applied a sun protecting lotion to her face everyday for the last 30 years of her life.
But she didn’t apply it to her neck. The difference is very stark at 70 years old. The skin on her face was wrinkled but her neck look absolutely worse in terms of age and skin damage.
But I think people really underestimate the impact of sun damage, particular if your skin is quite pale.
https://www.yalemedicine.org/conditions/sun-damage
This is considered a virtue among traditional Asian women.
https://pubs.rsc.org/en/content/articlelanding/2002/pp/b2012...
Vitamin D production is highly dependent on time of day and latitude. At latitudes closer to the poles, even extended sun exposure might not stimulate much vitamin D. You can find online calculators which show this for your location.
I mean, it's pretty clear that sun exposure damages the skin. And it's not just skin cancer but other pre-cancerous changes and just premature aging.
https://www.msdmanuals.com/home/skin-disorders/sunlight-and-...
That article isn't strictly wrong to say that exposure to sunlight is linked with melanoma, but it's linked to childhood sunburns and intermittent sunshine/sunburn. Sunburns are bad, sun is good.
> And perplexingly, outdoor workers have half the melanoma rate of indoor workers. Tanned people have lower rates in general.
I think it's also fair to say that exposure to the sun doesn't cause premature aging so much as not being exposed to the sun makes you look younger than you would otherwise - but of course that only helps if you're alive. Direct sun exposure reduces all-cause mortality. [1]
[1] https://onlinelibrary.wiley.com/doi/10.1111/joim.12251
Which is not surprising considering the need for sun exposure for things like vitamin D.
But I'm not sure mortality is the best measure? Maybe quality of life? Getting surgery to remove a basal cell carcinoma and having failed skin grafts (happened to my grandmother) seems like a heavy burden to cost of life not captured in mortality.
Anyone in the 2 and 3 range can build significant sun tolerance by being careful, 4 and 5s don't generally need sunscreen. Jury is out on skin cancer, Bantu people in Africa don't all die of melanoma, so clearly melanin is doing a lot of work here.
https://onlinelibrary.wiley.com/doi/10.1111/joim.12251
It reduces blood pressure.
https://www.nature.com/articles/s41598-017-11567-5
Folks out here worried about how wrinkly their skin might look at 75 when nobody cares instead of cardiovascular health though :)
I would've said so, too, before my GF got into the reef tank hobby. Corals are ridiculously sensitive to pretty much everything. Light, chemicals, nutrients, water flow, diurnal rhythms, you name it. It's fairly believable that something in the low parts per billion might affect them adversely, particularly organisms that are already stressed.
The political will to solve problems is a finite resource. Squandering it on trivial crusades is, IMO, one of the most wasteful and harmful decisions that could be made.
Gee, humanity had better act fast to protect that precious finite resource. What would our children and grandchildren think if we squandered our political will to solve problems?
Trivial to some upper class person in an air conditioned home who doesn’t want to think about bad things and who’ll survive no matter what is certainly not trivial to billions increasingly struggling to survive with no way to escape to greener pastures.
https://www.researchgate.net/publication/325157337_Social_cl...
Yes, if you are trying to change human beliefs and attitudes, you can't disregard human nature or behavioral psychology. Duh.
But is there anything functionally wrong with zinc oxide sunscreen? If not, why is it not available as the default option with chemical sunscreens available for those who want to go out of their way to not look pale?
Anyway, if you spend a lot of time in the sun or at the beach the functional problem with zinc oxide is pretty clear: it's harder to spread and put on. This might not seem like an issue but if you spend a lot of time dealing with it, the annoyance adds up.
https://www.hawaii-guide.com/blog/hawaii-new-reef-safe-sunsc...
Many of the dive boats and hotels will offer sunscreen out of a bulk pump, so depending on what you do on the islands, you probably don't need much on your own - just a small tube for your group will do.
Point is, the regulations to keep those ingredients out of the reefs have been mostly successful.
There are also reef-safe sunscreens that rub in much more clear.
This means: Put a largish drop on a fingertip and rub it in, then repeat, and repeat, and repeat. If you squeeze out enough that you need to keep it in the hand instead of on a finger, it's going to show.
Also a lot of people on Maui actually live there and aren't even tourists.
I love it a lot. Zinc Oxide is great for being a true "sunblock" (rather than merely "sunscreen") of broad-spectrum UV (instead of just UVA or just UVB/UVC). Also doesn't interact with endocrine system like many of the chemical sunscreens.
https://www.dermstore.com/eltamd-uv-clear-broad-spectrum-spf...
> Pentagon to permanently close Navy fuel tank that leaked petroleum into Hawaii water supply
https://www.usatoday.com/story/news/nation/2022/03/07/navy-f...
that and the literal pricing out of actual island natives from their own islands.
https://www.theguardian.com/technology/2021/dec/28/mark-zuck...
> Downs has heard that argument before. “One swimmer, one shower, does it pose a threat? But 500 swimmers and more than 500 showers?” The difference, he says, is all in the concentrations.
> Cláudia Mieiro, a marine biologist at the University of Aveiro in Portugal who was not involved in Downs’ study, remarked on the high concentrations of sunscreen chemicals found in the sand near the showers. The sand, she said, appears to be acting like a sink for these compounds.
Bathing is not a point source, so is covered by different legislation.
Point-sources can have higher concentrations in a small area, like the sand near the showers. These need to be addressed even if the non-point sources are also an issue.
Same for corals.
Yes and you can't change that, since there's already a ban.
> > Cláudia Mieiro, a marine biologist at the University of Aveiro in Portugal who was not involved in Downs’ study, remarked on the high concentrations of sunscreen chemicals found in the sand near the showers. The sand, she said, appears to be acting like a sink for these compounds.
Isn't that a good thing?
If you care about corals and marine life, and if you know that some people will not use the ideal sunscreen, you should prefer that sunscreen to be in the sand (where UV photodegradation may clean it out), rather than in the ocean: people going back into the ocean, or taking a shower at home (with the waste water then going... into the ocean) seems far worse.
So a ban + allowing showers so that the uncaught sunscreens ends up in the sand seems like the best possible outcome.
The two paragraphs after what I quoted address that, at least in passing.
> where UV photodegradation may clean it out
"May"?
The point is with the current system "Risk assessments for both sand and water samples at a majority of the sampling sites had a Risk Quotient > 1, indicating that these chemicals could pose a serious threat to beach zones and coral reef habitats."
The measured evidence is "Beach sands that are directly in the plume discharge of beach showers on three of the islands of Hawaii (Maui, Oahu, Hawai’i) were found to be contaminated with a wide array of petrochemical-based UV-filters that are found in sunscreens." (both quotes from https://www.sciencedirect.com/science/article/abs/pii/S03043... )
and "Oxybenzone ranged from 30 ng/L to 27,880 ng/L in near-shore waters in Hanauma Bay." - https://www.sciencedirect.com/science/article/pii/S004565352...
It's not staying in the sand. It's not photodegrading fast enough.
For bonus points, it's not like photodegradation doesn't have it own issues. As one of the linked-to documents points out, at https://link.springer.com/article/10.1007/s00244-015-0227-7 , "Benzophenones, including BP-3, are documented mutagens that increase the rate of damage to DNA, especially when exposed to sunlight."