It just doesn’t stop this summer!
First, Consumer Reports says that mineral sunscreens just aren’t effective after testing 13 of them. I totally disagree with them and elucidate my points rather, ahem, pointedly, right HERE.
Now, a reader sent me this article about the dangers of the sunscreen ingredient avobenzone reacting with chlorine in swimming pools to form toxic compounds! The media has been reporting on research published by Cheng Wang in the journal Chemosphere, and I appreciated the more scholarly breakdown of the research here.
A little summary for you of the Phys.org article:
Avobenzone, the most popular UV filter in the world (meaning it’s used the most in conventional sunscreens to block UVA light, and in FACT it’s the only chemical ingredients that DOES block UVA light!), breaks down into hazardous chemical compounds in water, accelerated by the presence of sunlight.
The report states that “the breakdown of avobenzone may take place on wet human skin,” and that the research “simulated the real situation in which a sunscreen is applied to the skin of swimmers.” The authors target chlorinated water in particular and say that copper salts (usually added to swimming pools to make them blue) are even worse, resulting in bromoform being formed. “This substance could provoke dysfunction of the liver and kidneys, along with nervous system disorders.”
Opposite of the Actual Research?
The actual research definitely says an acidic environment increases degradation (speeds it up) – BUT wait, chlorinated pools are basic, not acidic: the normal ph of chlorinated swimming pools is 7.2-7.8. “The optimum pH for pool water is 7.4, since this is the same as the pH in human eyes and mucous membranes. A pH of 7.4 also gives good chlorine disinfection.” (source)
So that acidic environment is actually the opposite of a chlorinated pool. What is up with the Daily Mail and Phys.org reporting incorrectly?
Let’s explore the research further.
Does Sunlight and Chlorine Degrade Avobenzone in Sunscreens?
I’ve tried to educate people for years about how quickly conventional sunscreens can break down and what better, safe alternatives there are for sun protection. Now here are some figures to dig into:
It sounds like under UV light, avobenzone’s half life is 126 minutes. I’m assuming that at least half the avobenzone has broken down into the other 2 substances at that point, chloro-avobenzone and dichloro-avobenzone. Those are quite unstable under sunlight and especially sunlight and water combined, with half lives of as little as 14 minutes.
Some of what this all turns into include benzoic acids and phenols, which are “quite toxic,” according to Albert Lebedev, one of the study’s authors – especially when they’re chlorinated.
This image from the study shows avobenzone being exposed to NaOCl (sodium hypochlorite) and water, and breaking down into chloro-avobenzone and dichloro-avobenzone – see the extra Cl and 2 extra Cl atoms there in the bottom two figures?
What’s also interesting is that sodium hypochlorite isn’t the most popular way of chlorinating a pool – calcium hypochlorite is.
So perhaps the reporting wasn’t quite as much to call home about (and toss your sunscreens) as it sounded at first.
But – don’t stop now. There are still PLENTY of reasons to ditch avobenzone in sunscreens and personal products forever!
For example: “Avobenzone is significantly degraded by UV light and normal day light. Therefore, it will be drastically reduced over time during the course of normal use. Control degradation studies have shown that 1 hour of sunlight exposure reduces avobenzone absorbance by 36%.” (PubChem, Oppen-Bezalel, in-cosmetics Group)
Why Ditch Avobenzone
Avobenzone, which was FDA approved in 1988 as a UVA filter, used to only be available under a trademarked name Parsol 1789. That meant it was more expensive to use in sunscreens and not seen all that often.
In the last few years, it’s able to be used in a generic form as avobenzone, and that coupled with the fact that it’s the only non-mineral ingredient approved to filter UVA rays, means that it’s in just about every conventional sunscreen you can find.
If it’s not, you’re not getting broad spectrum UVA/UVB protection anyway, so that’s no good.
But if avobenzone is so effective at filtering UVA rays, why ditch it?
- It does break down in the sun (drastically, see above) faster in water, and faster yet in chlorinated water (Kalister, 2016).
- When exposed to chlorinated water, more toxic compounds are created. (Trebse, 2016)
- The compounds avobenzone breaks down into are quite unstable – whether this effects us directly through our skin or indirectly through pollution in the environment (your kids accidentally ingesting pool water that a bunch of sunscreen has washed off into) isn’t conclusive. (Wang, 2016)
- As avobenzone degrades, which may be in less than two hours, it is no longer effective (or at least far less effective) at protecting you from UVA rays. You’ll never know it though, because UVAs don’t cause burns. They’ll just get you decades later with wrinkled skin and cancer.
- “It can degrade into some very harmful compounds, some of which are known carcinogens,” said Daniel Aires, a dermatologist with the University of Kansas Health System. “What isn’t known is how much is absorbed into the skin, or if it’s to a level that can cause or potentially increase the risk of cancer. But this is certainly alarming.” (The Kansas City Star)
- Even if avobenzone and all the compounds it degrades into aren’t absorbed through the skin (do you want your kids to be the guinea pigs??), I’m almost certain my kids drink gallons of pool water each summer (ew) and most certainly ingest whatever is washing off everyone else in the pool (grrrrrr).
- Next time I’m passing out all our sunscreens from our massive natural sun protection review, none of which ever include avobenzone and all are broad spectrum protection.
- By the way, if you don’t think sunscreens and their active ingredients including avobenzone are getting into the pool water (and hence our general water supply), they are.
- Chloroform is one of the byproducts as avobenzone breaks down and super toxic and may be a probable human carcinogen (the EPA says):
- “Chloroform evaporates very quickly when exposed to air. Chloroform also dissolves easily in water, but does not stick to the soil very well. This means that it can travel down through soil to groundwater where it can enter a water supply. Chloroform lasts for a long time in both the air and in groundwater…In humans, chloroform affects the central nervous system (brain), liver, and kidneys after a person breathes air or drinks liquids that contain large amounts of chloroform.” (Agency for Toxic Substances and Disease Registry, 1997)
- All the recommended preservatives for avobenzone are toxic or hormone disruptors or both.
- Avobenzone causes awful stains on clothing – even after you swim, if you change into clothes and it rubs off, you’ll get nasty rust-looking stains that only show up AFTER the clothing is exposed to water, usually in the wash. If you’ve ever experienced a load of laundry from your beach trip that was mysteriously ruined, your sunscreen may be at fault.
Even if you’re not concerned about health or don’t buy into the research as conclusive enough for you, perhaps practicality will win out. Who wants to wreck their clothes, spend a ton of time treating stains (that are really hard to get out) or have to shower before dressing every single time you wear sunscreen?
You’ll find avobenzone in an alarming number of products, like lipsticks, creams and other makeup.
It’s on my list of “ingredients to avoid at all costs.”
How about you?
Original article and pictures take www.kitchenstewardship.com site
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