Scientists have discovered that sunscreen from swimmers releases substantial amounts of polluting titanium dioxide (TiO2) into the sea and has the potential to harm marine life.
This work, which comes from research on beaches in the south of France, was presented at the Goldschmidt conference on geochemistry in Boston.
TiO2 is one of the most important ingredients of sunscreen, where it works as a protection against harmful UV rays, and most important regulatory authorities generally consider it safe for human use at concentrations in sunscreen.
However, concentrated TiO2 or long-term exposure may be toxic to a variety of fish and other aquatic organisms.
In many sunscreens TiO2 is present as small nanoparticles coated with protective chemicals. Because the particle size is so small, nanotitanium dioxide does not reflect visible light, but absorbs UV light, creating a transparent barrier that protects the skin from the sun's harmful rays.
The researchers have discovered that in water the nanoparticles tend to lose their protective coating under the influence of UV light or seawater composition that exposes the more toxic TiO2 to the aquatic environment.
The team measured TiO2 concentrations on three beaches near Marseille in France, as well as surveying bathers about how much they used sunscreen, and how often they used the water. The team found daily concentrations of 15 to 45 μg / L TiO2, which corresponds to several kg nanoparticles per summer season per strand.
"For example, with a small beach that holds around 3,000 people daily, we calculate that about 68 kg of cream per day can be delivered per day, or 2.2 tonnes over the summer, if we reasonably assume that half of the used creams 5 percent of titanium dioxide, this releases 1.7kg of titanium dioxide per day: That amounts to about 54kg in the two months of the high summer, which is a considerable amount, of course the sea is moving more or less continuously, so some the pollution with titanium dioxide will be spread, "said Jérôme Labille, principal investigator of Labex Serenade, Aix-Marseille Université and CNRS, Aix en Provence, France. "Nevertheless, we expect an accumulation of titanium dioxide in the coastal area, which could affect the animals there – in recreational areas with stagnant water, such as in lakes or saltwater swimming pools, there will be no dispersion and the accumulation is expected to be even more pronounced.
"It is important to keep this in perspective: titanium dioxide is a pollutant and we must take measures to try to reduce the amounts of TiO2 concentrated in the aquatic environment, where it can be harmful to fish and other organisms," he said. added. "Nevertheless, it is extremely important that sun worshipers continue to use sunscreen to protect the skin, pollution by titanium dioxide must be addressed by manufacturers and possibly legislation, and we have received good feedback from the manufacturers we work with."
The researchers note that in early July Hawaii prohibited certain sunscreens that were harmful to coral reefs (this was not due to titanium dioxide).
"The good news is that we are working on UV filters of nanoparticles and sunscreen formulas that reduce the potential damage caused by titanium dioxide We are looking to develop sunscreens that are designed safely, minimizing the release and toxicity of nanoparticles, so we expect a solution to this problem is not too far away, "Labille said.
"This work is of particular importance because it shows for the first time how nanoparticles from cosmetics can influence the aquatic environment." Previous work by our group has shown this for lakes and rivers, but this is the first study for the marine environment "Thilo Hofmann, from the University of Vienna, said.