New suspect in coral reef bleaching: sunscreen chemicals
It isn’t climate change killing off coral reefs, it’s the chemicals in sunscreen products.
That’s the stunning finding in a groundbreaking new study, published today in the journal Archives of Environmental Contamination and Toxicology.
“A chemical widely used in personal care products such as sunscreen, poses an ecological threat to corals and coral reefs and threatens their existence,” report the study authors.
“Oxybenzone (also known as BP-3; Benzophenone-3) is found in over 3,500 sunscreen
products worldwide, and pollutes coral reefs from swimmers wearing sunscreens and
through wastewater discharges from municipal sewage outfalls and from coastal septic
“Toxicopathological effects of the sunscreen UV filter, oxybenzone on coral planulaei
demonstrates that exposure of coral planulae (baby coral) to oxybenzone, 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 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
“A team of marine scientists from Virginia, Florida, Israel, the National Aquarium (US) and
the US National Oceanic & Atmospheric Administration, undertook the study. Lead
author Dr. Craig Downs of Haereticus Environmental Laboratory Virginia, said, “The use
of oxybenzone-containing products needs to be seriously deliberated in islands and
areas where coral reef conservation is a critical issue. We have lost at least 80% of the
coral reefs in the Caribbean. 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.”
“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 exhibited an increasing rate of coral
bleaching in response to increasing concentrations of oxybenzone. This is particularly
relevant for areas facing mass bleaching events including Hawaii.
“Between 6,000 and 14,000 tons of sunscreen lotion are emitted into coral reef areas
each year, much of which contains between one and 10% oxybenzone. The authors
estimate that this puts at least 10% 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.
According to MarineSafe, a campaign concerned with the impact of these products on
ocean health, there may be as many as 82,000 chemicals polluting our marine
environments, just from personal care use.
“Professor Alex Rogers of the International Programme on the State of the Ocean at
Oxford University, which established MarineSafe said, “Far too little attention is paid to
the chemicals entering the ocean and their destructive impact. We need better
understanding, testing and management to ensure that we are not eroding vital ocean
resilience through the careless use of marine-toxic ingredients.” IPSO’s 2012 State of
the Ocean report called for action to “prevent, reduce and strictly control inputs of
substances that are harmful or toxic to marine organisms into the marine environment”
recognizing its critical role in eroding the resilience of the ocean to the impacts of climate
“Since the 1970s, coral reefs have been devastated on a global scale. Regional weather
and climate events are often the cause of wide-scale mortality but the long-term
causative processes of sustained demise are often locality specific and increasingly
thought to be linked to pollution.
“Oxybenzone is found in a range of products from lipstick and mascara to sunscreen and
shampoo, it acts as a barrier to UV light, a task for which other ingredients are available.
It has already been identified as a threat to human health. The European Union’s
International Chemical Secretariat, established in the EU has listed oxybenzone on its
“Substitute It Now” list of substances that should be replaced and meets the criteria for
“Substances of Very High Concern.”
Executive Director Pat Lindquist of the Napili Bay and Beach Foundation of Maui, Hawaii
said, “This study raises our awareness of a seldom realized threat to the health of our
reef life at Napili Bay: chemicals in the sunscreen products visitors and residents wear
are toxic to young corals. As our mission is to protect and improve the health of our
popular bay and beach, we appreciate scientific input regarding threats to that
health. This knowledge is critical to us as we consider actions to mitigate threats or
improve on current practices. We hope to promote more use of sun-protective
swimwear which will benefit our reefs and bay, and have plans to investigate best
options in the coming year.”