Chemical sunscreens floating on the surface of the ocean can block the sunlight coral reefs in Hawaii need to survive, says professor
Two types of sunscreen, chemical and mineral, are available to protect the skin from the sun’s harmful ultraviolet rays, but chemical sunscreen is more popular although it can negatively affect coral reefs, said Esprit Saucier, an associate professor in the Faculty of Sciences. “If people don’t let the chemicals [contained in sunscreens] soak into their skin and go swimming,” she said, “it flushes off and you can see the oil chemical like a film on top of the ocean.”
She explained the chemicals block sunlight from passing through the water and reaching the corals. Corals are dependent on the sun for photosynthesis, which makes food for them to live off, and having chemicals from the sunscreen can disrupt this, she added.
Dr. Ember Christensen, a physician at the BYU–Hawaii Health Center said Hawaii banned sunscreens with oxybenzone and octinoxate in 2018, as both were harmful to the corals. Saucier also agreed, saying they are the disruptors in the marine ecosystem. “They’ll stop metabolic pathways and kill off the larva so [corals] end up not thriving,” she explained.
Mineral versus chemical
Christensen explained chemical sunscreen is less pasty to apply than mineral sunscreen. While mineral sunscreen tends to come off easier, she said it forms a protective barrier on the skin against the sun and offers better protection. “However, it’s heavier and can make you feel hotter when you sweat,” she said.
Mineral sunscreen contains zinc oxide or titanium dioxide, Christensen explained. These oxides make up the thick, white cream people apply to the skin, but she said it does not budge off the skin if used as directed.
In contrast, she said chemical sunscreens are lighter, often available as sprays or thin lotions, and it effectively protects the skin from the sun but can cause inflammation.“Would you rather have an inflammation reaction on your skin that will protect you but could cause rashes and allergic reactions,... or just that thick, heavy pasty stuff?” Christensen emphasized.
She said one common misconception about sunscreen she often addresses is the lack of understanding about SPF and its function. SPF, or sun protection factor, helps shield the skin from harmful sun exposure.“SPF 30 will block 97 percent of [harmful] sun rays,” Christensen said. She explained that using SPF 50 or 100 will not give us as much protection as an SPF 30. “It usually costs more money to buy the higher SPF sunscreens,” she said.
Skin cancer prevention
Lynae Lambert, a freshman from Colorado majoring in psychology, said she has been using sunscreen daily since her childhood due to being on a soccer team. She said she became aware of the risk of long sun exposure without sunscreen such as sunspots, wrinkles and skin cancer because of her father’s skin cancer diagnosis. Living in Colorado’s high elevation, closer to the sun, made sunscreen even more essential, she added.
Christensen said second-degree burns with blisters and wrinkling of the skin could lead to skin cancer eventually. “Just burning your skin is damaging to the DNA that can potentially cause cancer,” said Christensen.
Lambert recalled a time she forgot to pack sunscreen for a vacation in Fiji, and she had the worst sunburn. “I didn’t have a blister, but I had a really bad mark,” she explained. “I prefer reef-safe, but as a college student, I don’t have a lot of money,” she said. The term reef-safe typically means the sunscreen contains only mineral UV-blocking ingredients like oxide and titanium dioxide, says Save the Reef website, a non-government organization aiming to preserve the reefs. She explained she used reef-friendly sunscreen instead as it is much cheaper although it is not as effective as the reef-safe sunscreen.
Saucier said one thing to do to preserve the reefs is to wear rash guards instead of using sunscreen to limit the chemicals in the ocean. She said it takes a lot to educate people, especially tourists, to take care of the reefs through their choice of sunscreens. “Wear mineral sunscreen instead even if it’s hard to rub in, if putting one on cannot be helped,” Saucier explained.