Coral threatened by chemicals, including several in sunscreen, French study confirms

The French environmental health agency has confirmed the negative impact of certain chemicals on coral, including several substances present in sunscreens. With territories in three tropical oceans, France harbours ten percent of the world’s coral, which is already under threat from climate change.

Part of the coral reef system in the Mayotte lagoon. Coral is threatened by climate change, but also chemicals that end up in the ocean, confirms a French study. © Pierre René-Worms/RFI

The French Agency for food, environmental and occupational health (Anses), has urged the French government to limit – or enforce limits on – runoffs of chemicals that could harm coral reefs, which provide fifty percent of the earth’s oxygen, and are currently under threat.

While studies have shown that climate change, which warms and acidifies ocean water, impacts coral, Anses confirmed in its report published Monday that coral destruction is also caused by pollution linked to human activity, and that at least 15 to 20 chemicals that end up untreated in the ocean increases coral degradation.

Saving what's left of coral reefs

"The expertise shows that half of the evaluated substances can present risks to coral reefs and contribute to their degradation,” Anses said of its study looking at 53 substances, and warning that a lack of data means the number is probably underestimated.

Twenty percent of coral reefs have been “irreversibly destroyed” over the last decades, the report said, and only a third are in a satisfactory state.

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Anses looked at the impact of chemical substances at the request of the government and the French office for biodiversity, and used data available from French departments Guadeloupe, Martinique, Reunion Island and Mayotte.

The 53 substances in the study include hydrocarbons, pesticides, metals, microplastics, pharmaceutical products and UV filters found in sunscreen and cosmetics.

Sunscreen harms coral

The report highlights the impact of sunscreen on coral, identifying three toxic chemicals: oxybenzone, octinoxate and octocrylene.

Anses has previously asked the French state to restrict the use of octocrylene, which breaks down into benzophenone, an endocrine disrupter, which could keep coral from reproducing.

France said it would like to see such restrictions managed on a European level.

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In its report published Monday, Anses questioned allegations made by some French and international sunscreen brands that their products respect the ocean and environment.

“While this study does not address the evaluation of these allegations, the experts question their origin in the face of results of the literature analysis that shows a lack of specific data about the toxicity of the substances studied on coral,” the study wrote.

“The presence of one of these substances [oxybenzone, octinoxate or octocrylene] appears incompatible with the possibility of supporting such allegations.”

(with AFP)