Why Sunscreen is Bad for Coral Reefs

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Why Sunscreen is Bad for Coral Reefs

Chemicals from sunscreen can harm the coral reefs. / Photo by: Getty Images


As summer fast approaches, people are looking forward to spending their days on the beach and getting some much-needed vitamin D. However, the sunscreen we put on to protect ourselves from the harmful rays of the sun is also doing great damage to the world’s coral reefs. A recent study has found that sunscreen ingredients can pose a threat to ocean health.  

How Sunscreen Affects the Reefs

Recent studies have shown that sunscreen in many popular products damage coral. According to Ocean Conservancy, the main contributors are oxybenzone and octinoxate, which convert the UV rays that cause sunburn into harmless heat to human skin. However, once these chemicals are in the water, they, in fact, decrease the coral’s defenses against bleaching, causing damage to their DNA and hurting their development. Along with damage caused by other stress factors such as acidification of the oceans, water pollution, rising sea temperatures, and coral diseases, these damages prevent corals from reproducing and surviving in marine environments

Researchers in the study published in the journal Archives of Environmental Contamination and Toxicology found that the chemical oxybenzone has toxic effects on young corals, including endocrine disruption. Oxybenzone thus enhances the discoloration of corals or coral bleaching, a process in which corals reject symbiotic organisms and lose their color. The bleaching has prevailed in recent years due to the increase in sea temperatures.

The Mother Nature Network reported that a 2015 study found that only a small amount of sunscreen containing the ingredient oxybenzone is sufficient to break down the coral, causing it to lose its nutrients, turn into phantom white or bleach, and often die. The study was conducted in Hawaii and the United States (US) Virgin Islands after the researchers accidentally met a vendor waiting for another group of tourists and observed the "long oil slick" of sunscreen they would leave behind.

the National Park Service said that 4,000 to 6,000 tons of sunscreen enters reef areas annually. Based on new research, the toxicity occurs at a concentration of 62 parts per trillion. This is equivalent to a drop of water in an Olympic swimming pool, according to Omri Bronstein, the study author and a researcher at Tel Aviv University.

Once a beach-goer wears sunscreen and goes swimming, they carry these chemicals into the ocean. Tourists at the beach aren’t the only ones that spread the harmful sunscreen chemicals to coral reefs. Kids that wear sunscreens on playgrounds and athletes out for runs all come home and wash away the chemicals at home. The sunscreen they wash off can also end up in the sea through their bathroom drains. These chemicals can also enter marine ecosystems through sewage treatment plant outflows. Moreover, they are not usually removed by wastewater treatment systems since these systems are not designed to remove other pollutants.

Research presented at the International Coral Reef Symposium in June 2016 in Hawaii examined 327 coral colonies off the coast of Florida, Puerto Rico and St. Thomas, St. John and St. Croix in the US Virgin Islands for determining the reproductive potential of Elkhorn corals, a threatened coral species that appeared healthy. In some locations, these corals were observed to not be able to reproduce because of their lack of sperm or eggs. They were then dubbed as “zombie corals” by the researchers because, according to them, they were essentially walking dead and would eventually die out.


Coral reefs can be damaged and affects their ability to reproduce and survive because of the chemicals from sunscreens. / Photo by: Igor Borisov via 123rf


Taking Steps Against Reef Destruction

In the Pacific archipelago, the nation of Palau is the first country in the world to ban reef toxic sunscreens. The president of Palau, Tommy Remengesau Jr., signed a law in October 2018 that would ban the sale and use of sunscreen that contained 10 banned ingredients, including oxybenzone. Tourists who bring sunscreen into the country will have them confiscated, and the products will then be fined up to $ 1,000. It was reported that one of the reasons he signed the law was due to a 2017 study that showed that sunscreen was found in the famous Jellyfish lake in their country, which was closed for a year due to the decreasing number of Jellyfish.

A state legislation in Hawaii was signed in May 2018 that would ban the sale of sunscreen that contained oxybenzone and octinoxate. However, the bill would not ban its use. Therefore, tourists could pack sunscreen products bought in other states and continue using it on the islands.

In spite of these steps taken by some states, medical professionals are worried that the ban will lead to an increase in cases of humans developing skin cancer and other skin conditions. Time Magazine reported that the researchers were careful to note that they are not advocating that swimmers stop wearing sunscreen, which protects against skin cancer. Instead, they called on consumers to think carefully. Sunscreen containing titanium oxide or zinc do not damage reefs, according to the National Park Service. In addition, swimmers can cover their torso with long-sleeved shirts or other garments to reduce their use of sunscreen.



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