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France sued for failing to stop spread of killer seaweed in Brittany

Seaweed cleared on the coast at Saint Michel-en-Greve, Brittany
Seaweed cleared on the coast at Saint Michel-en-Greve, Brittany Benoît Tessier/Reuters

The family of a man who died on a Brittany beach in 2016 is suing the French state for not doing enough to fight the growth of seaweed, which releases toxic gas. His death is suspected to have been caused by green algae that which has covered France's north-western coast due to soaring summer temperatures.


In September 2016, Jean-Rene Auffray went for a jog with his dog on the beach in Hillon, on the bay of Saint-Brieuc in Brittany. He never came home.

Auffray was 50-years-old and in good health. His family found his body in a patch of seaweed – and they believe that’s what killed him.

Rotting seaweed produces hydrogen sulphide, a highly toxic gas that smells of rotten eggs. Animals and people have fallen ill or died over the years after breaking the dried top layers of the seaweed and letting out the gas.

On Thursday Auffray’s brother, wife and three children filed a lawsuit asking for 600,000 euros in damages from the state and local authorities for not doing enough to stop the green algae they believe responsible for his death.

“He died in a place where the authorities knew there was a lot of green algae, but they did not do an autopsy until it was too late to determine the cause of death,” Hermine Baron, a lawyer working on the case, told RFI. “It is not normal when a sudden death occurs in places like this, that they did not systematically do an autopsy.”

There are many indications that Auffray died because of the gasses emitted from the seaweed. "From a strictly scientific point of view, we will not have the exact answer," admits Baron. "But we have a lot of concordant evidence that it was caused by the green algae.”

The lawsuit is asking for damages, but the lawyer says it’s not so much about the money: “It’s a way for them to get acknowledgement that their husband, father and brother died because of the green algae. They want, above all, that measures be taken to prevent this from happening again.”

Green algae plan

Authorities have put in place a plan to fight the green algae tides in eight Breton bays. It involves working with farmers to reduce nitrates leaching into the water.

The first such plan was introduced in 2009, after a horse died of the gas and the rider fell ill. In 2011, 36 wild boars were found dead, likely intoxicated by the gas.

Like all plants, green algae thrives on nitrogen, and nitrates flow into Brittany’s bays from rivers washing away animal waste and fertiliser from the intensive pig farming in the region.

Auffray’s family say the state has not done enough to regulate agriculture, even with the green algae plan. Courts have agreed. The state has appealed a 2018 ruling condemning the Saint-Brieuc Armor metropolitan area to pay a 550,000 euro fine for not doing enough to prevent the green tides in the bay.

The family also blames the city for not warning the public of the dangers of the toxic seaweed.

“There were a lot of signs that this area was toxic, but the general public did not know it,” says Baron. “When our victim was jogging, there was no information. The previous mayor had put up a sign, but it was taken down."

Killer seaweed

The shores of Hillon today are carpeted with seaweed, and the beaches are closed, with signs warning of toxic gas.

Hotter than usual weather has made for a perfect storm and the green algae is overwhelming the town charged with clearing it off the beaches. So they have closed the beaches, at the height of the summer holiday season.

The one seaweed treatment plant in the region, which dries and pulverises it into dust, closed its doors on 3 July because there was too much arriving. Odour and gases were overwhelming workers and nearby residents.

The plant says it received 2,000 tonnes of green algae in three days in June, compared to 6,000 tons during the entire year of 2018.

Seaweed remains piled up on closed beaches.

“Closing beaches is the only solution they have. It’s the complete sign of powerlessness,” says Yves-Marie Le Lay, the head of two local groups fighting the influx of green algae.

In 2020, activists will mark the 50th anniversary of the first official alert of toxic green algae. Le Lay says not much has been done since then: “Fifty years later the only way we have to fight against it is to close beaches. That’s unbelievable. We’ve spent millions of euros to purify the water, to reduce nitrates in the rivers. It’s possible there is less, but it’s still much higher than the amount needed to spark these green tides.”

In 2016 the concentration of nitrates in the water was 31.8 milligrams per litre, compared to 51 milligrams per litre 15 years earlier. But Le Lay says to really reduce seaweed growth, the waters must contain less than 10 milligrams per litre. Current plans aim for 15 milligrams by 2027.

New ways of farming

There is a solution to the green algae problem: reduce nitrates flowing into the water, which means moving away from intensive agriculture.

“The phenomenon of green tides is based on two things: nitrates and light,” says Le Lay. “On these two aspects, there’s only one that we have control over: nitrates. You can’t change the weather.”

He would like to see the Brittany coast protected like the areas around natural sources like Vittel, in eastern France: “In those zones, there is a perimeter where there are no nitrates.”

This does not mean no agriculture, just a different kind.

“At Vittel there is farming. But it’s done properly because water costs something there,” says Le Lay. “Here in Brittany, rivers are considered to be worthless, so the price we pay is green tides.”

Lawyer Baron says a shift in farming in Brittany will be difficult to achieve: “The state has been pushing for intensive farming in Brittany for years. And now that we have these consequences, reversing the process is complicated. There are a lot of economic interests at play.”

But a lot is at risk, not just public health.

“If a person dies just by crossing a river, imagine the state of the flora and fauna in these muddy areas,” says Le Lay. Many of the river deltas feeding into the Brittany bays are natural reserves. Seaweed threatens them: “Biodiversity is threatened. If entire estuaries are affected, in these areas, nothing is living. Everything is dead.”

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