image: Scientists from the Faculty of Chemistry of the Lomonosov Moscow State University have demonstrated in their research the nature of hazardous chemical compounds formed as a result of the breakdown of avobenzone, a component of many sunscreen products, when it interacts with chlorinated water and ultraviolet radiation. view more
Credit: Albert Lebedev
Scientists from the Faculty of Chemistry of the Lomonosov Moscow State University have demonstrated in their research the nature of hazardous chemical compounds formed as a result of the breakdown of avobenzone, a component of many sunscreen products, when it interacts with chlorinated water and ultraviolet radiation. The chemists have presented the results in the Chemosphere journal.
The chemists from the Lomonosov Moscow State University have chosen avobenzone as an object of research. Avobenzone is a derivative of a chemical compound, named dibenzoylmethane. This choice has been conditioned by the fact that this is the most popular UV filter in the world. Avobenzone was patented in 1973 and in 1988 approved by FDA (the Food and Drug Administration, a federal agency of the United States Department of Health and Human Services), dealing with control and supervision of food products, pharmaceutical drugs, cosmetics, tobacco products and some other categories of products. The ability of avobenzone to absorb ultraviolet light in a wide range of wave lengths has ended in its widespread use in the following products: lipsticks, creams and other cosmetics.
Sunscreen products, containing avobenzone, are applied by millions of people all over the world. Chemical UV filters like avobenzone absorb ultraviolet light due to the peculiarities of their structures. Absorbing ultraviolet radiation avobenzone translates it into waves with other length, which aren't harmful for the skin (in other words, it translates energy of light into thermal energy). Thus the substance in itself is safe, however, the Russian scientists have managed to prove that in water solution it's capable of breaking down into hazardous chemical compounds.
The scientists from the Lomonosov Moscow State University have defined the products forming as a result of the breakdown of avobenzone in chlorinated water and under the sunlight. These experiments simulated the real situation, when a sunscreen, applied on the skin of swimming people, gets into contact with the water in swimming pools. The breakdown of avobenzone may take place right on the wet human skin, on which a sunscreen is spread.
The chemists have revealed that avobenzone breaks down in the water, forming various organic compounds, belonging to the classes of aromatic acids and aldehydes, phenols and acetyl benzenes. Phenols and chlorinated acetyl benzenes have turned out to be the most toxic products. The latter ones and, in particular chloracetophenone, enter into the composition of lachrymatory mixtures, used by police for disrupting meetings.
Albert Lebedev, Doctor of Chemistry, one of the project authors says: "On the basis of the experiments one could make a conclusion that a generally safe compound transforms in the water and forms more dangerous products. In spite of the fact that there are no precise toxicological profiles for the most established products, it's known that acetyl benzenes and phenols, especially chorinated ones, are quite toxic."
Chromatomass spectrometry became the basic research method. This reliable and effective method allows conducting qualitative and quantitative analysis of the most complex mixtures of chemical compounds.
Albert Lebedev continues: "Studying the products of transformation of any popular cosmetics is very important as very often they turn out to be much more toxic and dangerous than their predecessors. In principle, basing on such researches, one could obtain results, which could restrict or even put under a ban the usage of one or another product, and preserve health of millions of people."
At the moment the scientists are studying the transformation of avobenzone under conditions of chlorination and bromination of fresh and sea water. During chlorination or bromination of sea water the number of the breakdown products of avobenzone will be even wider. And if water contains copper salts (which are added into many swimming pools for getting nice light-blue color), then bromoform is formed in large quantities. This substance could provoke dysfunctions of liver and kidneys, along with nervous system disorder.
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Journal
Chemosphere