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Scientists have warned that sunscreen chemicals are accumulating in marine environments at alarming levels, posing a serious threat to marine life and coral reefs. A new review published in the Marine Pollution Bulletin highlights the need for urgent research into the impact of these pollutants, which persist in the ocean and could have far-reaching ecological consequences.
With global sunscreen sales rising rapidly, researchers estimated that between 6,000 and 14,000 tonnes of ultraviolet (UV) filters wash into coral reef zones every year. These chemicals enter the ocean directly from swimmers or through wastewater, where they act as pseudo-persistent pollutants — substances that are constantly replenished, making them a long-term presence in marine ecosystems, they added.
Oxybenzone and octinoxate, two of the most common UV filters in sunscreens, have been linked to coral bleaching, deformities in coral larvae and reduced fertility in fish, the report indicated. Oxybenzone, in particular, is known to disrupt hormone function in marine organisms. In response, places such as Hawaii and Palau have introduced bans on sunscreens containing these chemicals to protect their fragile ecosystems.
Research has detected sunscreen pollutants in marine environments worldwide, from popular tourist destinations to remote waters such as Antarctica, the authors highlighted in the research paper. Once in the ocean, these chemicals do not easily break down and can accumulate in the tissues of marine species, potentially affecting entire food chains. Wastewater treatment plants are largely ineffective in removing these contaminants, meaning they continue to circulate in the environment.
Coral reefs, already struggling with the effects of climate change, are particularly vulnerable. Studies show that even low concentrations of certain sunscreen chemicals can cause corals to bleach within days. Bleaching occurs when corals expel the symbiotic algae they rely on for energy, leaving them weakened and more likely to die. Scientists have warned that the combined pressures of warming oceans and chemical pollution could accelerate reef degradation.
Beyond corals, sunscreen pollutants are affecting a wide range of marine organisms. Studies have found that UV filters can disrupt the growth and reproduction of algae, sea urchins, and fish. Because many of these chemicals are fat-soluble, they can accumulate in the tissues of marine animals and move up the food chain, raising concerns about their impact on larger species, including those consumed by humans.
Despite the growing body of evidence, much remains unknown about how different sunscreen formulations interact with marine life, the authors noted. They called for more extensive studies on a variety of marine species and ecosystems, as well as the development of standardised testing methods to assess toxicity. A lack of regulatory oversight has allowed potentially harmful chemicals to remain in widespread use, they added.
Some governments have already taken action. Hawaii, the US Virgin Islands and Palau have enacted bans on the sale of sunscreens containing oxybenzone and octinoxate, while other regions are considering similar measures. At the same time, there is a push for manufacturers to develop ‘reef-safe’ sunscreens that use alternative ingredients such as non-nano zinc oxide or titanium dioxide, which are believed to be less harmful to marine life.
Public awareness is also growing, the researchers noted. Tourists visiting sensitive marine areas are being encouraged to take precautions, such as wearing protective clothing to reduce the need for sunscreen, choosing environmentally friendly products and avoiding swimming immediately after applying sunscreen. Some destinations, including Hawaii’s Hanauma Bay, have introduced measures to educate visitors about the impact of chemical sunscreens and promote responsible tourism.
The scientists warned that without intervention, the cumulative effects of sunscreen pollution could contribute to the decline of coral reefs and the disruption of marine food webs, with consequences for biodiversity and coastal economies worldwide.
The concerns were published in Ecotoxicological effects of sunscreen derived organic and inorganic UV filters on marine organisms: A critical review.