The surface of Lough Neagh, Ireland’s largest body of fresh water (392 km2), is crisscrossed with waves. A storm is passing through the island, and no fishermen have ventured out on the water since Toome, a village in County Antrim with lough access (pronounced “lock”), located in Northern Ireland, almost entirely surrounded by marshy areas. Between the aquatic weeds, its water is brown.

“At the end of October [2023), there was still lots of toxic algae and it smelled strongly, like a gas leak. With the coolness and winds of autumn, the algae has disappeared,” explains Gerard McCourt, an eel fisherman on Lough Neagh for thirty years. In the summer of 2023, it witnessed the most massive bloom of blue-green algae – plant-looking bacteria called cyanobacteria – ever observed on this lake. However, it provides 40% of Northern Ireland’s drinking water and is home to Europe’s largest commercial eel fishery.

Satellite images from the European Copernicus service from September 4, 2023, showed the alarming extent of the pollution of Lough Neagh: a large part of its surface appeared emerald green from space. Worried, Gerard McCourt reduced his outings on the lake and stopped his children from paddle boarding there. Naturally present in fresh water, cyanobacteria produce toxins (cyanotoxins) when they proliferate, dangerous for humans and animals (dogs are very vulnerable).

Louise Taylor, another resident of Lough Neagh and founder of the Love our lough association, says she stopped swimming there and no longer drinks tap water. “I don’t trust NI Water [Northern Ireland’s only water treatment company]. She says the water is safe to drink although it has an earthy taste and smell. But where is his data on water quality, asks the activist met in Toome. Has the company adapted its treatment methods since the lough was polluted? We don’t know anything about it at all. »

Wastewater receptacle

Since the summer of 2023, the photos of Lough Neagh and the mobilization of local residents have caused a sudden awakening. Until then, local media and politicians focused their attention on a fragile process of reconciliation, twenty-five years after the Good Friday peace agreements which ended the civil war between Catholics and Protestants. Environmental issues took a back seat in a province focused on its economic dynamism, where agriculture still employs 2.2% of the working population (compared to 0.8% in the rest of the United Kingdom).

“The reasons for this pollution go back several decades,” according to Mark Emmerson, biologist at Queen’s University in Belfast, Lough Neagh being the receptacle of wastewater from surrounding homes but above all, too large quantities of phosphates and nitrogen resulting of the intense surrounding agricultural activity.

“Northern Irish farmers are allowed to spread manure on fields. Some of these nutrients are found in rivers and loughs. And especially since the precipitation was intense this summer,” explains the expert.

These nutrients in quantity can explain the proliferation of algae, just like global warming, points out Mark Emmerson, the temperature of the surface of the ocean in the North Atlantic having been historically high this summer, increasing the humidity in the air and the precipitation, therefore soil drainage. The abundance of zebra mussels in the lake, an invasive species, may have amplified the bloom: “These shellfish ingest the micro-organisms and filter the lough water but it seems that they do not digest the cyanobacteria,” explains Mark Emmerson.

Review agricultural models

As the sun’s rays penetrate more easily into the filtered water lake, the photosynthesis of the blue-green algae is even more stimulated. “There is a great risk that this pollution will return from one year to the next. What we are observing in Lough Neagh is a phenomenon that could happen elsewhere in Northern Europe,” adds the academic. The presence of cyanobacteria has been detected in County Fermanagh and on beaches in the north of the province. They have also proliferated in Scotland, on the vast Loch Lomond and even in the seemingly wild Loch Eck, in the Argyll and Bute region.

Gerard McCourt makes a direct link between the pollution of the lough and the scarcity of eels: “Zebra mussels eat the micro-organisms at the expense of the flies in Lough Neagh. These local insects almost disappeared while the small eels fed on them. Our cooperative has 70 fishermen, but this summer, only twenty-eight boats renewed their licenses, and there were no more eels to catch at the end of July, whereas until then, we fished until Halloween. I stopped making a living from fishing, it’s no longer possible when you have a family and a mortgage,” he laments.

The solutions are not simple: it is difficult to get rid of invasive species and it would be necessary to thoroughly review local agricultural models, introducing mixed farming to better fix nutrients in the soil (while Northern Ireland essentially practices ‘breeding). Activists deplore local particularities.

“Unlike the rest of the UK, Northern Ireland does not have an independent environment agency, it is DAERA [Department of Agriculture, Environment and Rural Affairs], the Department of Agriculture, which is responsible for protecting the lough, but its priority is agricultural production,” laments John Barry, specialist in political ecology at Queen’s University in Belfast.

Environmental activists criticize the agriculture ministry for not carrying out sufficient studies on the health of the lake. “We need an independent research center to monitor the lough,” insists Louise Taylor. There was one, operated by the University of Ulster, but it closed more than a decade ago. “Lough Neagh is dying but the Ministry of Agriculture is handcuffed to agricultural lobbies, it continues to subsidize pig and chicken farms,” also accuses James Orr, director of the NGO Friends of the Earth Northern Ireland.

“Extremely worrying situation”

In addition, Stormont, the Northern Irish Assembly, was dissolved in February 2022 due to the refusal of the DUP, one of the two main parties in the province (unionist, pro-British), to participate in the regional government due to a dispute on the status of Northern Ireland post-Brexit. Since then, the latter has operated without an executive or Parliament and civil servants manage day-to-day affairs, which makes any decisive action to protect the lough difficult.

Finally, few parties are concerned about the environment: the Greens remain in the minority, the last Minister of Agriculture in office, Edwin Poots, a member of the DUP, was criticized for having doubted the reality of climate change.

Only the Social Democratic and Labor Party (SDLP) stepped up to demand emergency measures and suggest the purchase of the lough by the public authorities. The bed and surroundings of the lake are owned by a British aristocrat, Nicholas Ashley-Cooper, Count Shaftesbury, who activists accuse of not caring enough about the state of the waters. The latter did not refuse the sale in principle, but no negotiations have yet been able to begin, in the absence of a regional executive. And London has refused to come to the rescue: the pollution of the lough is “intolerable”, Steve Baker, the Secretary of State for Northern Ireland to Rishi Sunak, the Prime Minister of the United Kingdom, recently judged, but it does not t is “not the responsibility” of the UK government.

“The situation on Lough Neagh is extremely worrying and we take it very seriously,” acknowledges a spokesperson for the Northern Ireland Department of Agriculture. “A panel of experts was brought together to establish recommendations to improve water quality following detections of blue-green algae this summer. The ministry will study all the options proposed, knowing that they will have to be assessed in the context of the strong constraints exerted on public budgets and in the light of the priorities of the future regional executive [when a government agreement has finally been reached. found],” adds this spokesperson.