The UV filter in your sunscreen is a lifesaver for your skin, but once you go in the water and it washes off, it damaging or even killing coral reefs, and negatively affecting the fertility of fish and sea urchins, as well as negatively impacting mussels, green algae, and dolphins. It’s gotten so bad that the National Ocean Service suggests that swimmers make sure to choose sunscreens with chemicals that don’t harm marine life – sometimes called “coral-safe” sunscreen.
Metal and nutrients in the ocean
But that’s only the beginning. Researchers from the University of Cantabria and the Institute of Marine Sciences of Andalusia in Spain just released a study, published in the journal Environmental Science and Technology, about the different compounds that sunscreens release into seawater – significant amounts of metals and inorganic nutrients.
These metals and inorganic nutrients are released into the waters sometimes quickly, sometimes slowly – it all depends on the amount of UV light.
Researcher and study lead author Araceli Rodriguez-Romero and her colleagues took samples of Mediterranean seawater and added to it a typical sunscreen that would be available in stores. Like most sunscreens, it contained titanium dioxide. They watched how the sunscreen released its metals and nutrients into the samples of seawater.
The results: researchers found that aluminum, silica, and phosphorus released from the sunscreen the quickest under both dark and light skies.
The scary part? They estimated that on a normal summer day, beachgoers in sunscreen could increase in the concentration of aluminum in the oceans by 4% and titanium by nearly 20%.
More research is needed to figure out how the high concentration of these metals and nutrients, which typically exist at low levels in seawater, might be influencing the human body, said researchers. But it’s already clear that sunscreen runoff harms many parts of the marine ecosystem.
Rodriguez-Romero doesn’t advocate a complete ban on sunscreen, but something more like harm reduction. “People need to protect themselves against the harmful effects of the sun,” she told Inverse. “Marine environmental scientists and cosmetic companies must work together in order to create a sunscreen safe for the marine environment and, of course, for human health.”
The study was conducted by lead author Araceli Rodriguez-Romero, Ph.D. at University of Cantabria, Gema Ruiz-Gutierrez, Ph.D. at University of Cantabria, and Javier R. Viguri, professor of chemical engineering, at University of Cantabria, and Antonio Tovar-Sanchez, tenured scientist, at the Institute of Marine Sciences of Andalusia.