Are sunscreen filters, designed to protect the skin from the sun’s aggressions, toxic to humans and the environment? According to Philippe Lebaron, Professor of Microbiology and Marine Ecology at the Faculty of Science and Engineering of Sorbonne University, certain molecules whose harmfulness is proven, and yet used in many products, present a real risk to health and marine environments. Maintenance.
Creams, milks, gels, dry oils… Sunscreen products are essential to protect against the sun’s rays during this summer period. “Sunburn” is mainly caused by UVB rays. UVA rays are responsible for premature skin aging,” says the French Competition and Consumer Affairs Department (DGCCRF), which recommends limiting the length of exposure.
But some molecules, present in the composition of sunscreens designed to shield against ultraviolet rays, can be dangerous, both for humans and marine environments. Professor Philippe Lebaron, a specialist in marine microbiology, explains why.
What are these molecules and what are they used for?
There are two main types of sun filters. Mineral filters, composed of titanium and zinc oxide and organic filters. The latter are always composed of a mixture of molecules, because there is no single molecule that can cover the entire spectrum of UV rays. In general, manufacturers combine 3 to 5 molecules, with ingredients that make the cream easy and pleasant to apply.
To protect your skin, you don’t take just any sunscreen
Are these molecules dangerous?
Several serious scientific studies have demonstrated, in a proven way, the harmfulness of some of these organic molecules. In particular oxybenzone (also called benzophenone-3) and octocrylene. The latter compound is inexpensive and easy for manufacturers to use.
But these molecules pass through the skin. Studies have shown their presence in the urine of some children in China, but also in breast milk, in breastfeeding women. They present the same health risks as pesticides or endocrine disrupters[such as fertility, growth, behavioural problems, but also possible causes of certain cancers, N.D.L.R.]. Obviously, octocrylene and oxybenzone must be banned.
What are their effects on the environment?
There is a lot of talk about their impact on coral. Corals are a very important marine ecosystem for reproduction and therefore for biodiversity. Orders have been issued to prohibit the use of these filters, particularly in the Palau Islands, Micronesia, but also in Hawaii[these bans are to come into force in 2020 and 2021 respectively]. In December 2018, the Biodiversity and Biotechnology Laboratory of Banyuls (Pyrénées-Orientales) published a study highlighting the toxicity of octocrylene on coral.
How do they spread into the sea?
These molecules present in sunscreens are hardly soluble in water. When they diffuse into bathing waters, via the skin, they stick to the solid surfaces they encounter. Samples taken by the Banyuls Laboratory have revealed a significant concentration of these substances in the sand, but also on the walls of marine micro-organisms, algae or crustaceans, even very small ones, such as phytoplankton.
Are these effects reversible?
These molecules degrade very slowly. Once they are fixed, it is very difficult to get rid of them. This can take several months.
Does this pollution have an impact on humans?
The real question that the scientific community must ask itself on the subject is how these molecules are transmitted via the food chain. Shrimp feed on microorganisms that can be contaminated, oysters and mussels, which are water filterers, are also exposed. And of course the fish, consumed by humans, which reach the end of the food chain.
Even very small organisms can be contaminated with organic filters in sunscreens. Phytoplankton are microscopic algae.
How to protect yourself against it?
To pave the way for public health action, accurate scientific data must first be collected. They do not currently exist. It cannot be said whether the impact of this concentration of molecules in marine organisms is too great for consumers. For example, the national average estimate of this concentration in potentially exposed coastal fish should be established.
In addition, the toxicity of these molecules to humans and the environment is multifactorial and very complex. It is not only in sunscreens that are a problem. Similar molecules are present in shampoos or other cosmetic products.
Is there an alternative?
Creams containing mineral filters are not free of toxicity. But like organic molecules, they remain interesting for their effectiveness in filtering UV rays – and it is essential to protect yourself from solar radiation. However, pharmaceutical companies must invest in research on natural molecules, even if we will never be able to obtain perfectly satisfactory protection, only with this type of compound. As often as possible, however, they should be combined with effective and non-toxic organic filters.
How to find your way around?
Beware of claims by some sunscreen manufacturers that their filters are safe for the environment, based on scientific studies commissioned by them. Not that these studies are false, but they are conducted at a time T, in a particular context and do not necessarily make sense. Some manufacturers invest more in communication than in improving their products. For consumers, this is the path of the fighter.