Toxic green algae: The disease poisoning French Brittany's waterways and coast

Euractiv

21 hours ago

Almost 10 years after a jogger died on the Breton coast due to toxic gases from algae blooms linked to farm pollution, the region's president says preventative measures have been taken. But environmental groups warn that the threat is far from over.
Once again this summer, the Brittany region in western France is plagued by a perennial problem: green algae.
As temperatures rise, parts of the coastline are regularly covered with tons of foul-smelling seaweed. As the organisms decompose, they release hydrogen sulphide – a highly toxic gas.
On 24 June, a French court ruled that the death of a jogger in 2016 on a beach in northern Brittany was due to inhaling this gas. The court accused Paris of failing to comply with EU and national water protection rules.
But the tragedy was not an isolated case: Since 1989, an estimated 40 animals and three people have died as a result of these algae. The cause of the green tides is no mystery – it is rooted in the region's livestock-intensive farming, the backbone of Brittany's economy. Brittany's pork obsession Brittany dominates France's pig industry. The region is home to nearly 60% of the nation's pigs and supports some 20,000 jobs.
The landscape is dotted with large-scale industrial pig farms that produce nitrogen-rich manure, which is then spread over fields as fertiliser.
But crops cannot absorb all the nitrates in the soil, leaving the surplus to wash into groundwater, rivers, and eventually the sea, where it fuels the growth of green algae.
In a 2017 investigation, French journalist Inès Léraud revealed the 'silence factory', whereby agricultural lobbies and political leaders downplay the scandal to protect the lucrative pork sector.
Loïg Chesnais-Girard, socialist president of the Brittany region, told Euractiv that the situation has since improved. 'Everyone has understood that there were excesses'.
Nitrate levels in Breton waterways have actually fallen from 53 milligrams per litre in the 1990s to a steady 25 mg/l since the 2010s. Largely because there are fewer pigs, which leads to a corresponding reduction in nitrate pollution.
'Animal production peaked in the 2000s and has been declining on average ever since', Chesnais-Girard said. Brittany's pig population dropped from 8.4 to 6.8 million between 2001 and 2022.
But despite some improvement, the region is running out of time to meet its goal of bringing nitrate pollution down to 15 mg/l by 2027.
One solution, Chesnais-Girard explains, is to plant hedges – which slow down the flow of nitrates into waterways. Manure tanks are also checked for leaks. Downstream, trucks collect green algae from beaches and deposit it in drying sheds. Putting lipstick on a pig For critics, however, these efforts fail to address the fundamental issues.
"The problem is not solved", warns Stéphane Galais, spokesperson for Confédération Paysanne, a left and green-leaning farmers' union.
'There are still closed water catchment areas, and some places still have 50 mg/l of nitrates in the water," he told Euractiv.
Galais added that, while nitrate pollution has subsided in line with falling livestock numbers, due to animal health and economic crises, 'the same structural problem' remains. He slammed the government's nitrate plans as ineffective, excessively complex, and influenced by 'powerful agri-food lobbies'.
The union believes that the issue of nitrate pollution can only be resolved by addressing the dominance of the pork industry in Brittany, which it calls a 'historic error'.
'Without a real plan to move beyond industrial livestock farming, it is impossible to solve the problem.' A soft spot for pigs But moving on from pig farming will not be easy.
Whilst Chesnais-Girard agrees that in particularly polluted areas, a reduction in pigs might be beneficial, he is careful to avoid making farming into a culture war.
"Weighing in too heavily on the issue of ecological change will push voters to extremes," he warned.
Unsurprisingly, the pig industry rejects the finger-pointing.
"We must stop blaming pig farmers, who all have manure tanks with specific management rules and comply with spreading regulations,' Anne Richard, director of the French pork industry association INAPORC told Euractiv.
Despite the French court's ruling, the national government still has a soft spot for its pigs. On 12 August, President Emmanuel Macron rubberstamped a controversial law easing the expansion of livestock farms.
It's a decision Galais deplores: 'In Brittany, we need to do the exact opposite,' he lamented.