An estimated 6,000-14,000 tons of sunscreen are deposited into coral reef areas of the sea every year. The chemicals we rub onto our skin might help prevent skin cancer but we're only just beginning to understand the environmental impact of sunscreen – and the initial assessments are not looking good. But early stage research suggests that nature might provide a solution to this emerging problem if we can mimic the way that some plants and animals protect themselves from the sun.
Sunscreen is vital to helping prevent skin damage from ultraviolet radiation (UVR) that can cause melanoma and other skin cancers. They contain a number of ingredients that act as UVR filters, absorbing and scattering the radiation and stopping it from reaching the skin. Many studies have demonstrated the benefits of regular sunscreen use, including long-term studies in Australia that have shown reduced skin cancer rates..
The potential problem is that many ingredients used in sunscreen products are synthetic organic molecules, like those used to make plastics. These molecules are designed to be highly stable and so they don't break down when they enter the environment. As a result, sunscreen ingredients are detectable in species including fish, sea mammals such as dolphins and even marine dwelling birds.
The impact of these molecules on the environment isn't fully understood but is a growing focus of research. We know that some filters have a similar structure to the hormone oestrogen and mimic can its action. This can cause hormonal changes and even alter the sex characteristics of some fish. UVR filters have also been linked to coral bleaching.
These concerns are being monitored by many regulatory agencies. The European Chemicals Agency has listed eight out of the 16 most commonly used sunscreens in Europe as a potential threat to the environment and health, raising the ultimate possibility of a ban. Fears about damage to coral reef systems has already led to bans of particular sunscreen ingredients in some coral hotspots such as Hawaii.
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