The sunscreen that snorkelers, beachgoers and children romping in the waves lather on for protection is killing coral and reefs around the globe. And a new study finds that a single drop in a small area is all it takes for the chemicals in the lotion to mount an attack.
The study was conducted in the US Virgin Islands and Hawaii several years after a chance encounter between a group of researchers on one of the Caribbean beaches, Trunk Bay, and a vendor waiting for the day's invasion of tourists. Just wait to see what they'd leave behind, he told the scientists - "a long oil slick". His comment sparked the idea for the research.
The study determined that a tiny amount of sunscreen is all it takes to begin damaging the delicate corals. It documented three ways the ingredient oxybenzone breaks the coral down, robbing it of nutrients and turning it white.
Cities have sewer outfalls that jettison tainted wastewater away from public beaches, sending personal care products with a cocktail of chemicals into the ocean. Research for the new study was conducted only on the two islands. But across the world each year, up to 14,000 tonnes of sunscreen lotions are discharged into coral reef, and much of it "contains between 1 and 10 per cent oxybenzone", the authors said. They estimate that places at least 10 per cent of reefs at risk of high exposure, judging from how reefs are in tourism areas. "The most direct evidence we have is from beaches with a large amount of people in the water," said John Fauth, of the University of Central Florida. "Another way is through wastewater streams. People come inside and [use] the shower [and they] forget it goes somewhere."
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The study was published in the Archives of Environmental Contamination and Toxicology. Fauth co-authored the study with Craig Downs of the nonprofit Haereticus Environmental Laboratory and Esti Kramarsky-Winter, a researcher at Tel Aviv University in Israel.