Water quality in Irish rivers is going in the “wrong direction”, the Environmental Protection Agency has warned.
While the quality of 197 river bodies has improved, 269 have deteriorated — a 3% reduction in river quality since 2015.
Some 56% of river bodies are at high or good quality with the remainder at moderate or worse.
“The declines seen in our rivers’ indicators are an early warning signal that trends in water quality may be at a turning point and heading in the wrong direction,” an EPA report warns.
Most pollution is caused by too much nitrogen and phosphorus entering waters.
There has been a long-term reduction in nitrogen and phosphorus but recent data indicates that levels are beginning to rise again.
The main sources of these nutrients are agriculture — slurry and chemical fertilisers, and sewage — waste water treatment plants.
If the pollution is not addressed there will be further declines in water quality in the future, the environmental watchdog has warned.
However, there has been some positive changes, with serious pollution continuing to decrease, according to the report Water Quality in 2017: An indicators Report for Ireland.
Only two river bodies were seriously polluted in the latest reporting period — Aughboy River, Co Wexford, and Ahavarraga, a stream that flows through Dromcollogher, Co Limerick.
Historically, there were 91 seriously polluted water bodies in the late 1980s.
Another positive finding is that fish kills are at an all-time low with only 14 reported last year, compared to 31 in 2016.
During the worst years — 1987 and 1989, there were over 100 fish kills annually.
Good progress has been made in tackling serious pollution in the country’s rivers but some areas of the country need attention.
The decline of river quality in the north-west is worrying while rivers, such as the Tolka in Dublin are regularly affected by fish kills.
Of the 24 catchments surveyed over the last two years, only five showed an overall improvement in the number of river bodies classified as satisfactory.
The five water catchments rated as “high or good” based on their biological quality included Colligan-Mahon in Co Waterford; Lee, Cork Harbour and Youghal Bay in Co Cork; and Tralee Bay in Co Kerry.
Director of the EPA’s Office of Evidence and Assessment, Matt Crowe, said the signals in the report were “not good”. Water quality was still getting worse in some areas despite improvements in others.