Sunscreen Found Harmful to Coral Sampled on Kaua‘i

Waters sampled off Po‘ipū beach, Kauai’s popular tourist destination and premier snorkel spot, were found to have levels of oxybenzone of 281-419 parts per trillion. Photo by Ruby Pap

The state Department of Land and Natural Resources is asking all ocean users in Hawai‘i to avoid sunscreen containing oxybenzone, also known as BP-3, due to scientific research showing the chemical’s harmful effects on coral. New, unpublished data show Kauai’s reefs are also at risk.

“Sunscreen chemicals wash of swimmers, surfers, paddlers, spearfishers, divers, and other ocean users,” said Dr. Bruce Anderson, administrator at the DLNR Division of Aquatic Resources. “Even if you’re just sunbathing on the beach, using beach showers will wash chemicals into the ocean. Researchers have found oxybenzone concentrations in some Hawaiian waters at more than 30 times the level considered safe for corals.”

Dr. Craig Downs, of Haereticus Environmental Laboratory in Virginia, published research in Hawai‘i last year, spurring DLNR’s request for ocean users to avoid sunscreen containing the harmful chemical.

His original research contained ocean water-sampling data from O‘ahu and Maui, but did not include Kaua‘i’s waters. However, last month, Downs shared with For Kaua‘i Newspaper some yet-to-be-published data about Kaua‘i; and the results show high concentrations of BP-3 at select North and South Shore locations.

On the left is a healthy, juvenile coral, about 5mm long. On the right is a coral exposed to oxybenzone for eight hours. Photo by Archives of Environmental Contamination and Toxicology

Downs’ original work published in 2015 in the Archives of Environmental Contamination and Toxicology did two things overall: It quantified in the lab how much BP-3 it takes to have toxic effects on coral larvae (planulae) and coral cells; and it measured concentrations of BP-3 in reef waters around the Caribbean and Hawai‘i.

The results of the lab experiments showed that at BP-3 concentrations as low as 72 parts per trillion (PPT) coral cells exhibited toxic effects. For the coral planula toxic effects were observed at 139 PPT.

Oxybenzone is an endocrine and developmental disruptor, causes DNA damage and cell proliferation, and increases the rate of coral bleaching. Deformities observed in planulae make them unable to swim and form new coral colonies. As an endocrine disruptor, BP-3 disrupts the entire hormone system, acting like a birth control pill, and severely affecting coral’s reproductive capacity. BP-3 also induces overgrowth of the skeletal system, essentially “encasing themselves in their own coffin,” said Downs. All of this puts coral reef health at risk and reduces the resiliency of the reef to climate change.

The published study also analyzed water samples taken from reef sites in the Caribbean and Hawai‘i. Sites on O‘ahu and Maui were contaminated between 0.8-19.2 parts per billion (PPB). Concentrations were higher in areas with more people in the water.

In the follow-up study to be published within the year, Downs sampled several other locations in Hawai‘i, including Kaua‘i. Samples revealed high BP-3 concentrations at Lumaha‘i of 468 PPT, with 130 people in the water or at the beach.

What do sunscreen products do to marine organisms? This picture shows a 96-hour exposure to oxybenzone concentration of 100 parts per billion, at 10 percent of photosynthetic active radiation — what a coral would see at 1 pm in the afternoon during the summer solstice. Coral on the left is the control; coral on the right is after the 96-hour exposure. Photo by Haereticus Environmental Laboratory

“It was a surreal and horrifying day because it was the first time I ever witnessed a number of groups spraying on the aerosol sunscreen when they were waste deep in the water,” Downs said.

Po‘ipū samples ranged from 281 to 419 PPT, also above the toxic threshold. Hanamā‘ulu Beach also had high concentrations, around 200 PPT, but this was an unusual day with lots of picnicking families present on a holiday weekend.

Downs said when you look at the big picture swimmers are a small but locally significant source of pollution. Sewage is a huge source of BP-3 globally, as well as other personal care products. But the problem is pervasive wherever there are people and coral reefs, especially in visitor-destination areas.

The take home message here is to stop using sunscreen containing BP-3. Even some sunscreens labeled “reef safe” contain BP-3, so it is important to read the label. Avoid oxybenzone, oxtinoxate, avobenzone or avobenzine, ethylhexl methoxycinnamate, homosalate, or octisalate/octocrylene. Some of the safe alternatives are sunscreens containing non-nanotized zinc or titanium oxide.

In the meantime, state Sen. Will Espero, D-‘Ewa Beach, is planning to introduce a bill in the next Legislature banning such sunscreens in Hawai‘i.

• Ruby Pap is a Coastal Land Use Extension Agent at University of Hawai‘i Sea Grant College Program. She can be reached at rpap@hawaii.edu.