The Environmental Protection Agency (EPA) has voiced concern after new data showed a sharp rise in nitrogen concentrations across Ireland’s major rivers, but stressed that “swift and targeted action” could deliver visible improvements within a year.

The agency’s latest Early Insights Nitrogen Concentration Indicator Report found that average nitrogen concentrations at 20 representative monitoring sites increased by 16% in the first six months of 2025 compared to the same period in 2024.

These sites, located at the most downstream points of Ireland’s largest rivers, serve as indicators of broader catchment health.

Speaking on the Agriland live stream at the Ploughing yesterday, programme manager at the EPA, Jenny Deakin described the figures as “disappointing”, noting that they follow several years of declining nitrogen levels.

“We had seen improvements taking place in recent years, with fertiliser use coming down and efficiencies going up.

“But unfortunately, when we look at the country as a whole on a net basis, we have seen a decline for the first six months of this year. It is 16%, which is a substantial increase," she said.

Despite the setback, Deakin emphasised that nitrogen is only one element of overall water quality, which is assessed through multiple measures, including phosphorus, oxygen, and biological indicators such as insect and fish populations.

The EPA programme manager said the latest report provides a “snapshot in time” rather than a definitive trend, and stressed the need to build on recent progress.

“We would really like to see the momentum continue because there is a lot of good work going on.

“If action is taken now, we can see improvements as soon as next year, given the relatively quick travel times of nitrogen in our river systems,” she said.

The EPA highlighted that challenges remain most acute in the south and south-east, where intensive farming practices, soil type, and climate conditions combine to drive higher nitrogen levels.

However, the EPA programme manager pointed out that both eastern and western catchments saw increases in the latest data.

Deakin called for continued commitment from farmers and policymakers, warning that water ecosystems cannot wait.

“Fish can’t take a holiday out of the water if it’s too dry or too wet," she said.

“We need to build enough resilience in the system so that weather doesn’t tip the balance.

"The encouraging thing is that if we act now, we can see the benefits very quickly."