The alert threshold for exposure to hydrogen sulfide, a potentially deadly gas that emanates from the putrefaction of green algae, was lifted on Friday two days after it was shot on a beach in the Bay of Saint-Brieuc, the prefecture announced. of Côtes d’Armor. .
“As part of monitoring the health risk of exposure to hydrogen sulfide emanating from the putrefaction of green algae, it was detected in the commune of Hillion at the Saint-Guimond beach site that the threshold of alert, established by the health authorities at 1 ppm (part per million), on the night of July 20, 2022 at 03:45 “, indicates the prefecture in a press release.
“Since then, the measured concentrations have not exceeded 1 ppm” and the alert system was lifted, adds the prefecture, which nevertheless invites the population that frequents the place to “respect the municipal decrees still in force.”
Algae that have proliferated for 40 years
This is the first time that an alert of this type has been triggered, since the establishment of a network of sensors on several Breton beaches.
Present in the sea in its natural state, green algae began to multiply more than 40 years ago on certain Breton beaches, where they feed on the nitrates spread by farmers in the fields and whose surpluses are transported by coastal rivers.
Since this summer, Air Breizh has been taking hydrogen sulfide readings at 12 measurement points in seven Breton bays from Douarnenez (Finistère) to La Fresnaye (Côtes d’Armor).
Information related to hydrogen sulfide emissions and health problems is available on the website https://www.bretagne.ars.sante.fr/les-algae-vertes, and the data collected as part of the network of sensors are available on the website of the Air-Breizh association https://www.airbreizh.asso.fr/.
Source: BFM TV
