To protect fragile coral reefs, Hawaii’s government is asking swimmers, surfers, and divers to avoid using sunscreens that contain the widely used ultraviolet light filter oxybenzone.
The state cites a recent study linking the chemical to deformities in the larvae of coral and associating oxybenzone exposure with an increase in the rate of coral bleaching (Arch. Environ. Contam. Toxicol. 2016, DOI: 10.1007/s00244-015-0227-7). In the bleaching process, symbiotic algae, which provide food and color to coral, leave stressed coral cells.
In the study, researchers led by Craig Downs, a cell and molecular biologist who directs the nonprofit Haereticus Environmental Laboratory, found oxybenzone could start harming coral at concentrations as low as 0.062 µg/L. They measured oxybenzone levels in Hawaiian waters ranging from 0.8 to 19.2 µg/L.
In light of these findings, Hawaii is asking people entering the ocean surrounding its islands not to use sunscreens containing oxybenzone.
“Sunscreen chemicals wash off swimmers, surfers, paddlers, spearfishers, divers, and other ocean users,” Bruce Anderson, administrator of aquatic resources in Hawaii’s Department of Land & Natural Resources, said on Sept. 3. He suggested using water-resistant sunscreens and products containing mineral sunscreens such as zinc oxide or titanium dioxide. Also recommended are rash guards, wet suits, and other protective clothing that reduces the amount of sunscreen people need to use.
The U.S. National Park Service says sunscreen concentrations are high in waters around popular reefs. Cosmetics consultant and chemist David Steinberg tells C&EN that salt water degrades oxybenzone, but he did not indicate how quickly that happens.
State Sen. Will Espero says he is drafting legislation for a Hawaiian ban on oxybenzone and a handful of other sunscreen ingredients suspected of harming coral.
Makers of sunscreens sold in the U.S. want to replace some of the sun-filtering chemicals now used with advanced molecules widely used in Europe. But the Food & Drug Administration has not approved the newer sunscreens.
FDA considers human health, not environmental impacts, when approving sunscreen ingredients.