Stéphane Mulliez, Director General of ARS Bretagne, recalled the "duty of information and transparency that we owe to our fellow citizens with regard to the impacts of hydrogen sulphide and the impacts of the presence of green algae on our coasts", during of a press conference near Rennes.

Thus, from Friday, the sensors will increase from 4 to 12 in different bays of Côtes-d'Armor and Finistère affected by this phenomenon.

The High Council for Public Health has given a "very clear benchmark in terms of hydrogen sulphide levels", namely 1 ppm in the air.

These sensors will record the rates every quarter of an hour which can be consulted on the Air Breizh site, an association approved by the State.

If the threshold is exceeded, the protocol provides in particular for information to local authorities and populations, greater collection of algae on the coasts and beaches affected and a strengthening of site access bans.

Present at sea in their natural state, green algae began to multiply more than 40 years ago on certain Breton beaches, where they are nourished by nitrates spread by farmers in the fields and whose surpluses are transported by coastal rivers.

Collection of green algae in the bay of Saint-Brieuc, in Morieux on July 26, 2011. DAMIEN MEYER AFP/Archives

Asked about the importance of their presence before the start of the summer season, the "Mr. Green Algae" of the region, the sub-prefect Étienne Guillet, estimated that 2022 risked "being in the fairly strong years".

Regarding a boat designed specifically to collect green algae, Mr. Guillet specified that the ship could be put in water “at the end of July or the beginning of August” and would operate in the bay of Saint-Brieuc and/or in the bay of La Fresnaye.

Finally, as part of the plan to combat the proliferation of green algae (PLAV), extended from 2022 to 2027, the water agency will mobilize ten million euros in aid over three years under territorial contracts .

The rate of contracting of farmers of green algae berries could increase from 10% to 40% in three years, indicated the prefecture of Brittany.

© 2022 AFP