Coral reefs under attack from cancer-protecting sunscreen

An international team of marine scientists have discovered that oxybenzone – a common chemical found in sunscreens and other cosmetic products – is killing off coral reefs around the world.

The chemical poses an ecological and existential threat to corals and coral reefs and is especially toxic to juvenile corals. Oxybenzone induces coral bleaching, which is causing mass coral mortalities worlwide. The chemical also damages the DNA of corals, leaving adult corals less able to reproduce and can result in potentially deformed or sick offspring. Oxybenzone is also an endocrine disruption and causes the juvenile coral to encase themselves with their own skeleton, leading to death.

The scientists determined that oxybenzone, which is found in over 3,500 sunscreen products worldwide, pollutes coral reefs – not only from swimmers wearing sunscreens but also through wastewater from municipal sewage systems. While oxybenzone pollution is found mostly in swimming areas, it can also occur on reefs 8 to 32 kilometres from the coastline.

“Coral reefs are the world’s most productive marine ecosystems and support commercial and recreational fisheries and tourism,” says one of the study’s co-authors, John Fauth from the University of Central Florida. “In addition, reefs protect coastlines from storm surge. Worldwide, the total value of coral reefs is tremendous. And they are in danger.”

According to the researchers, the highest concentration of oxybenzone was seen in Trunk Bay in the Virgin Islands National Park at 1.4 parts per million. While it does not sound like much, the study discovered that the lowest concentration to pose a toxicity effect was as low as 62 parts per trillion, the equivalent to a drop of water in six and a half Olympic-sized swimming pools. In parts of Hawaii, concentrations of oxybenzone were found to be 19 parts per billion, which means they pose a significant ecological threat.

Lead author of the study Dr. Craig Downs of the non-profit Haereticus Environmental Laboratory in Virginia says: “The use of oxybenzone-containing products needs to be seriously deliberated in islands and areas where coral reef conservation is a critical issue. We have lost at least 80 per cent of the coral reefs in the Caribbean.”

According to Downs, even a small effort to reduce oxybenzone pollution could make the difference between life and death. But without reducing the chemical, other reef restoration efforts “will achieve little if the factors that originally killed off the reef remain or intensify in the environment.”

The researchers acknowledge that sunscreen is important in protecting against skin cancer, but they urge beachgoers to choose oxybenzone-free sunscreens or sun-protective swimwear.


Photo credit: WorldFish, flickr/Creative Commons

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