Estimates vary on how much sunscreen ends up in the sea, but even a little is too much say researchers.
Sunscreen is an important tool to protect against skin cancer, but scientists say many brands are potentially toxic to marine life and may be killing the oceans.
Estimates vary as to how much sunscreen enters the oceans each year, but Cinzia Corinaldesi, associate professor of ecology at the Polytechnic University of Marche in Italy told the Guardian she estimates 20,000 tonnes is washed off tourists every year in the northern Mediterranean alone.
Dr Craig Downs, another leading researcher and head of the non-profit Haereticus Environmental Laboratory, thinks that between 6,000 and 14,000 tonnes are released in coral reef areas each year.
Two chemicals in particular concern researchers, the ultraviolet filters oxybenzone and octinoxate, although there are others that may be harmful. Campaigners now want there to be an international consensus on what constitutes a “reef friendly” sunscreen.
According to Corinaldesi some filters and preservatives “caused complete coral bleaching even at very low concentrations. Since then, we have continued to test several [sunscreens], including some ‘eco-friendly’ products, on different marine organisms and have found that some sun products cause abnormalities in embryos and larvae.”
She added that other marine organisms may be at risk, including “phytoplankton, small crustaceans, molluscs and fish, which support food webs, and other organisms such as sea urchins, which are ecosystem engineers and essential for the creation of marine habitats.”