Northern Ireland

Over 800 severe water pollution incidents reported in 2023, with sharp increase blamed on toxic algal blooms

Greenhouse gas emissions increasing, rise in phosphates and nitrates in rivers, while warmest year on recorded

Agriculture, Environment and Rural Affairs Minister Andrew Muir has said he feels a sense of shame at the environmental crisis affecting Lough Neagh
Algal blooms on the surface of Lough Neagh (Liam McBurney/PA)

More than 800 severe water pollution incidents were reported last year, a sharp increase largely due to the rise in toxic blue-green algal blooms in Lough Neagh and connected waterways.

The number of “substantiated” or severe pollution incidents increased by 21% from 676 to 821, with 128 serious algal blooms, according to the latest environmental statistics report.

While the number of water pollution incidents is trending down, the report does reveal increases in phosphorus and nitrate concentrations in rivers, a rise in greenhouse gas emissions and the warmest mean temperature at 11° Celsius since records began in the mid-19th century.

It was also the second wettest year after 2002 with over 1,000 millimetres of rain recorded.

Heavy rain is set to hit on Sunday
2023 was the second wettest year since records began (Danny Lawson/PA)

Greenhouse gas emissions increased year on year between 2020 and 2021 from 21.4 million tonnes of carbon dioxide equivalent to 22.5m, with agriculture contributing over six million, the highest level since a base year of 1990.

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Total emissions over the period decreased from 29.2m tonnes.

Environmentalists are linking the rise in phosphorus and nitrate levels in rivers, which are in part blamed for the Lough Neagh blooms, directly to Stormont’s 2012 Going for Growth strategy that they claim promoted large scale industrial farming.

James Orr of Friends of the Earth, said: “These figures are sobering and a reminder we are fast becoming the dirty corner of Europe. They paint a dark picture of a country at war with nature.

James Orr, Friends of the Earth NI director
James Orr, Friends of the Earth NI director

“It is appalling to see these figures not improving and getting worse such as the rise in phosphorus pollution in the big increase in water pollution incidents.

“This explains the algal blooms in Lough Neagh and the pollution source from factory farms and human sewage.” He linked Going for Growth to the rise in phosphorus and nitrate levels.

Nitrate levels of over 10mg per litre in 2023 were double the amount a decade ago, while the amount of phosphorus has also increased substantially. The standard for safe nitrate levels for drinking in the UK is 50mg per litre but 10mg in the United States.



The algal blooms are listed under other water pollution incidents as they cannot be directly attributed to farming, industry, domestic, NI Water or transport.

A total of 165 high and medium severity incidents were investigated during 2023, an increase from 89 the previous year and also attributed to the algal blooms.

Alliance MLA John Blair
Alliance MLA John Blair

“Years of division and stalemate have diverted our attention from the issues that directly affect the people of Northern Ireland daily, such as the environment,” said Alliance MLA John Blair.

“Neglecting to allocate sufficient resources for environmental protection will lead to substantial costs in the future. These costs will have not only environmental implications but also economic and social implications.

“Indeed, we are already starting to see these implications through the Lough Neagh crisis.”

In a survey published as part of the report, 78 per cent reported being “very or fairly concerned about the environment”. Climate change and illegal dumping of waste and litter were the most cited concerns.