Tackling Northern Ireland’s nutrient pollution problem at source: The role of the Office for Environmental Protection

Chief Scientist at the Office for Environmental Protection (OEP), Professor Robbie McDonald, lays out what actions his organisation is taking to help tackle nutrient pollution in Northern Ireland.

Unfortunately, we are now all too familiar with the ongoing environmental crisis in Lough Neagh. Stark images of this natural treasure choked by algal blooms rightly cause alarm for the state of the Lough. But more widely, they vividly show what happens when nutrient pollution – a major cause of the Lough’s deterioration and that of other waters – goes unchecked.

In the right place, nutrients are essential for life. In the wrong place, in excess and unmanaged, they become harmful.

In our 2024 report on drivers and pressures causing biodiversity loss, we highlighted the role of nutrient pollution in nature’s decline. Our analysis found that the quantities of nutrients entering the Northern Ireland environment are unsustainable.

Nutrient pollution sources

The majority of nutrients, primarily nitrogen and phosphorus, causing problems in Northern Ireland, are imported for the agri-food industry. The greatest quantity is in millions of tonnes of animal feed materials shipped in from South America and elsewhere, as well as manufactured and mined fertilisers from Morocco and China. These feeds and fertilisers often provide more nutrients than animals and crops need, meaning slurries and run-off carry the excess into waterways.

Human sewage pollution is a further significant part of the problem and the Northern Ireland wastewater system is over-capacity and under ever-increasing pressure.

Nutrients from wastewater, animal slurry and run-off pollute rivers, loughs and coastal waters, harming water quality and habitats. They fuel algal growth, some forming the now notorious algal blooms.

In the worst case scenario, toxic algal blooms can affect human and animal health and drinking water supplies.

What is the OEP doing about it?

We were established in Northern Ireland and England to hold governments to account for their environmental commitments, legal obligations, and to advise on changes to environmental law. The deterioration of individual sites is part of a bigger picture. With the evidence showing nutrient pollution is a key problem for Northern Ireland, we will now do what we can to tackle the overall causes. By doing so, we can use our powers, including our enforcement powers, to best effect.

In 2024, we investigated the Department of Agriculture, Environment and Rural Affairs’ (DAERA) ammonia advice (known as the ‘Operational Protocol’) on new planning applications. We initiated legal action to ensure the guidance was revised and became legally compliant.

This year, we are assessing where our enforcement powers can best be used to help tackle the causes of nutrient pollution, both from wastewater and from the agri-food industry. This work includes:

• assessing the Northern Ireland wastewater system and focusing on its impacts on protected sites, including Belfast Lough
• scrutinising the effectiveness of the existing Nutrients Action Programme (NAP) to present a formal report before the Northern Ireland Assembly
• scrutinising proposals for a new NAP and advising the DAERA Minister and MLAs so this important vehicle for change can deliver the improvements needed
• commissioning an independent assessment of new measures proposed in NAP consultation

A thriving environment is not a luxury or a ‘nice to have’. It is essential to underpin a thriving economy and society. There are no quick fixes when tackling nutrient pollution. Everyone must play their part, and there will be difficult decisions to make. We are committed to doing all we can. Watch this space.

Professor Robbie McDonald
OEP Chief Scientist