Sandy says:
I was reading this article at National Geographic and wondered what kind of sunscreen you recommend that won’t kill the coral reefs.  Can you help?  And is this really a problem?

Right Brain retorts:

Who doesn’t love the colorful and diverse ecosystem found at coral reefs? Even a logician like Left Brain can appreciate the beauty of these sites. Unfortunately, coral reefs are dying around the world. There are a variety of reasons like coastal development, overfishing, pollution and global climate change which individuals have little ability to change.  However, the article you cite says some environmental scientists think the sunscreen you use may also be killing these systems.

Death by sunscreen

According to a recent paper published in the journal Environmental Health Perspectives, certain sunscreen ingredients have been shown to cause destruction of the coral reefs. In their experiments, they showed that chemicals like parabens, ethylhexylmethoxycinnamate, benzophenone-3 and 4-methylbenzylidene camphor induce a viral infection of algae living in the corals which leads to bleaching. The authors go on to say that 4000 - 6000 tons of sunscreen is washed off beach goers annually and that this may be part of the problem. They recommend avoiding sunscreens that contain ingredients harmful to coral.

Not all scientists are convinced

While most of the media will report this as definitive news, some scientists question the conclusions made by this limited study. Specifically, they have four primary criticisms.

1. Concentration issues. The amount of chemicals shown to have an effect is over 10x that which is likely to occur in seawater around reefs.
2. No detection. They didn’t actually test the water near coral reefs for sunscreen chemicals.
3. No correlations. Researchers haven’t shown a correlation between popular sunbathing/snorkeling reefs and bleaching levels. If it were a problem caused by people’s sunscreens, places with more people would have more bleaching than those with less. They don’t.
4. Forgot pollution. They also forgot that the same chemicals are found in other personal care products that get washed down the drain and eventually end up in the ocean. Sunscreen use may be a much smaller contributor.

So, your sunscreen use may not be as much of a problem as the original paper’s authors suggest. Don’t you just love science?

Beauty Brains bottom line:

Right now there is not enough information to tell whether sunscreens are really killing coral reefs. The effect is probably overblown in this paper. However, there is proof that some ingredients can theoretically harm them, so if you want to remove this as a concern for you, avoid sunscreens that contain the following (if you’re going anywhere near a coral reef).

Butylparaben
Methylparaben
Ethylhexylmethoxycinnamate
Benzophenone-3
4-methylbenzylidene camphor

Instead, consider using products that contain zinc oxide or titanium dioxide.