A new study published this week in the journal Archives of Environmental Contamination and Toxicology has found that a chemical widely used in personal care products such as sun screen, poses an ecological threat to corals and coral reefs, threatening their existence.
Oxybenzone (also known as BP-3; Benzophenone-3) is found in over 3,500 sun screen products worldwide. It pollutes coral reefs from swimmers wearing sun screens, and through wastewater discharges from municipal sewage spillage and from coastal septic systems.
The study comes less than two weeks after NOAA declared the third-ever global coral bleaching event and warned that locally produced threats to coral – such as pollution – stress the health of corals and decrease the likelihood that they will resist bleaching, or recover from it.
Toxic effects of the sun screen UV filter, oxybenzone, on coral planulae (baby coral) demonstrates that exposure of the coral to the chemical produces gross morphological deformities, damages their DNA, and, most alarmingly, acts as an endocrine disruptor.
The latter causes the coral to encase itself in its own skeleton leading to death. These effects were observed to be as low as 62 parts per trillion, the equivalent to a drop of water in six and a half Olympic-sized swimming pools.
Measurements of oxybenzone in seawater within coral reefs in Hawaii and the U.S. Virgin Islands found concentrations ranging from 800 parts per trillion to 1.4 parts per million. This is over 12 times higher than the concentrations necessary to impact on coral.
The research team involved in the study included marine scientists from Israel, Virginia, Florida, the U.S. National Aquarium and the U.S. National Oceanic & Atmospheric Administration.
Among the Israeli researchers were two from Ben Gurion University of the Negev.
Prof. Ariel Kushmaro is head of the Environmental Biotechnology Lab, The Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, The Ilse Katz Institute for Nanoscale Science and Technology and National Institute for Biotechnology in the Negev. Researcher Yona Lichtenfeld is a member of the university’s Department of Life Sciences.
“We have lost at least 80% of the coral reefs in the Caribbean,” warned lead study author Dr. Craig Downs of Haereticus Environmental Laboratory Virginia.
“Any small effort to reduce oxybenzone pollution could mean that a coral reef survives a long, hot summer, or that a degraded area recovers. Everyone wants to build coral nurseries for reef restoration, but this will achieve little if the factors that originally killed off the reef remain or intensify in the environment.”
Professor Kushmaro added, “There is widespread use of sun screens which utilize chemicals from the benzophenone group in sun and UV-intensive Israel. According to measurements not included in the article, similar concentrations of benzophenone have been found near the coral reefs in Eilat.
“Since it is likely that these chemicals are being washed off of swimmers’ bodies, it stands to reason that concentrations would be higher in swimming and snorkeling areas such as the coral reef reserve in Eilat,” the professor said.
The study found that oxybenzone is a photo-toxicant with adverse impacts exacerbated in light. But even in darkness, planulae were transformed from a motile (mobile) state to a deformed, sessile (immobile) condition and showed an increasing rate of coral bleaching in response to increasing concentrations of oxybenzone.
Between 6,000 and 14,000 tons of sun screen lotion are leaked into coral reef areas each year, much of which contains between one and 10% oxybenzone, the researchers said.
They estimated this puts at least 10 percent of global reefs at risk of high exposure, based on reef distribution in coastal tourist areas. This study is one of less than two dozen scientific studies that closely examine the impact of personal care product ingredients on marine organisms and habitats.