Green algae: in the Hillion, measuring toxic gases at Grandville Beach

The entire eastern part of Grandville Beach in Hillion is covered with a whitish crust of dried green algae. The ground here is too soft for assembly machines to walk on. Before going for a walk, Yves-Marie Le Lay settles down. Goelo Pentievre, president of the Tregor Defense Association, puts on a gas mask, turns on a hydrogen sulfide detector, and attaches a second device to one of his boots. After walking just a few meters, the detector beeps at the point where Yves-Marie Le Lay returns the algae. Black putrid mud under the crust. In some places the detector panics and reaches 100 ppm, its maximum level.

Dr. Pierre Philippe, informant

Ambulance doctor Pierre Philippe, informant in 1989, together with Yves-Marie Le Lay, President of the Trégor Goëlo Penthièvre Security Service. (Telegram / Elsa Gaultier)

Emergency physician Pierre Philippe, present next to Yves-Marie Le Lay, is well aware of the risks associated with inhaling hydrogen sulfide: “It’s poison.” In 1989, after the death of a 26-year-old runner, he sounded the alarm about the danger of serious accidents involving green algae. H2S is a potent toxicant that affects the respiratory system and the brain. According to the doctor, at a concentration of 100 ppm, the gas can cause suffocation. At 250 ppm, pulmonary edema. Inhalation above 1000 ppm can quickly lead to death. The risks associated with this gas are well known and controlled in the petrochemical industry. On the coast, an ambulance doctor witnessed several accidents. In 1999, he sounded the alarm again, but to no avail. “I had to wait another ten years.”

“Back to the sender!” “

Green Algae Yves-Marie Le Lay Determines Hillion Hydrogen Sulfide Level
Yves-Marie Le Lay, armed with a gas mask, measures the hydrogen sulfide content of green algae deposits at Granville Beach in Hillion. (Telegram / Elsa Gaultier)

According to Yves-Marie Le Lay, plans to grow green algae, launched in 2010, were to “pretend” they were dealing with the problem. He welcomes the harsh conclusions reached by the Audit Chamber in July on this issue: “If we no longer want green algae, we must change the agricultural model. Have you seen an elected official say we need to change production methods in watersheds? Today, the environmental activist intends to directly challenge the agri-food industry by sending a sample of rotting green algae to Cooperl: “Back to the sender!”.

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