Nano-sunscreen pollutes the sea
A recent study conducted at beaches in Southern France suggests that significant amounts of nano-Titanium dioxide (TiO2) are released into the sea. This nanomaterial can be detrimental to the environment and therefore bears presents a hazard to aquatic organisms.
TiO2 is an important component of sunscreen because of its protection against UV-radiation. Most regulatory bodies deem it safe for humans to use sunscreen at the concentrations that are present in these products. However, high concentrations of the nanomaterial or prolonged exposure could be toxic to a number of fish and other aquatic organisms.
In most sunscreens, TiO2 is present as a nano-sized particle coated with chemicals that exert protective characteristics. In this size it does no reflect visible light but absorbs UV-radiation, therefore providing a transparent barrier that protects the skin from harmful sun rays.
In this study, scientists found that the nanoparticles lose their protective layer in water due to the influence of UV-rays or the composition of water. As a consequence, toxic TiO2 is released into the aquatic environment. Data was collected at three beaches near Marseille, France by measuring TiO2-concentrations and surveying beach visitors on how much sunscreen they used and how often they entered into the water. The concentrations found were between 15 and 45 μg/L of TiO2, which adds up to several kilograms of nanoparticles per summer season and beach.
Dr. Jérôme Labille (Labex Serenade / Aix-Marseille Université / CNRS, Aix en Provence, France) explains this as follows : « At a small beach, for example, which about 3000 people visit daily, we estimate 68 kg of sunscreen being deposed in one day. A sunscreen contains 5% of TiO2 on average, making a daily value of 1.7 kg of titanium dioxide. In two months of summer, that adds up to 54 kg, which is a significant amount. The sea is more or less constantly in motion of course, which spreads the pollution of titanium dioxide to a degree. We still expect an accumulation of titanium dioxide in coastal areas, which can harm animal life in those regions. In recreational areas such as lakes or coastal baths there will not be such a spread of the nanomaterial, leading to an even stronger accumulation. It is important to remember that titanium dioxide is a pollutant and we have to take measures to reduce its concentrations in aquatic ecosystems because it can be detrimental to fish and other organisms. On the other side, it is important that sun lovers keep using sunscreen to protect themselves. The load of titanium dioxide should be reduced by producers and possibly via legislation. So far, we’ve received positive feedback from producers we work with.”
In Hawaii, some sunscreens were forbidden in early July because of their damage to coral reefs (though this was not due to titanium dioxide). Dr. Labille goes on to say: “The good news is that we are working on UV-filtering nanoparticles and sunscreen formulas which will reduce the possible damages caused by titanium dioxide. We are developing sunscreens that are “safe by design” because release and toxicity of nanoparticles is minimized. Because of this, we believe that a solution for this problem is within reach.”