Over half (56% or 1,317) of river water bodies assessed nationally over the period 2019-2022 are in high or good biological condition. The remaining 44% (1,045) river water bodies are in moderate, poor or bad biological condition. The number of river water bodies in bad condition has reduced to two. There has been no significant change in the biological quality of our rivers in 2022.
There were an additional three sites in the Q5 category (highest quality) during the 2019-2022 period, bringing the total number of these sites to 35 (1.2% of monitored river sites). These high-quality sites are important for supporting sensitive aquatic species and are vital reservoirs of biodiversity that help in river recovery.
The 2020-2022 data for nitrate in 1,305 rivers shows that 40% of river sites nationally have unsatisfactory nitrate concentrations (above 8 mg/l NO3). The south east has consistently had the highest nitrate concentrations over time which is associated with more intensive farming coupled with freely draining soils and lower effective rainfall. The annual averages in this region exceed concentrations that are likely to have a negative impact on estuaries and coastal water quality. The western and border areas have the lowest overall river nitrate concentrations. There has, however, been an increase in river nitrate concentrations in all regions over the 12 months from 2021 to 2022.
The 2020-2022 data for phosphate in 1,305 rivers shows that 28% of sites have unsatisfactory phosphate concentrations while the remaining 72% are at levels which support high (58%) or good (14%) water quality. Phosphorus losses in these catchments come primarily from runoff losses from agriculture on poorly draining soils and from waste water discharges. Phosphate levels in rivers fluctuate between years but have been generally stable over recent years. The highest river phosphate concentrations in the country are in the south east and south west.
Over half (55%) of the 224 lakes monitored national over the period 2020-2022 are in high or good biological quality with the remaining 45% in moderate or worse quality. The proportion of lakes at satisfactory quality (high and good) has remained relatively unchanged in recent years. These lakes are predominantly located in the west and south west. Most of the lakes that are in unsatisfactory biological quality are in the border region.
Over one third (36%) of lakes had unsatisfactory total phosphorus concentrations in the period 2020-2022. The majority of lakes with unsatisfactory total phosphorus concentrations, at levels that do not support good water quality, are located in the border region. Lakes with lower total phosphorus concentrations are predominantly situated in the west of the country.
This distribution tends to reflect the difference in the level of human activity, hydrogeology and soil conditions in these regions. Lakes in the northeast of the country have the highest total phosphorus concentrations that are also rising. Restoring these lakes to at least good status by 2027 represents a significant challenge as they often contain a historical legacy store of phosphorus in their sediments that is slowly being released over time.
The majority (91%) of our groundwaters are in a satisfactory condition, which is a positive outcome. One-fifth (20%) of groundwater monitoring sites over the period 2020-2022 had nitrate concentrations greater than 25 mg/l NO3 (considered as a high nitrate concentration). Although drinking water standards are occasionally exceeded at some sites, on average, groundwater nitrate concentrations are below the levels that may pose a widespread risk to human health.
Nationally, there has been an overall increase in groundwater nitrate concentrations since 2012/2013 when concentrations were at their lowest. The increasing nitrate concentration is most notable in the south east and midlands an east regions. Nitrate concentrations in the south east, midlands and east, and south west Regions have been consistently above levels that are needed to protect surface water ecology, particularly in our marine waters, since 2010. Nitrate concentrations in the western and border regions have remained low and relatively static since 2010.
There are localised issues in our groundwaters with elevated nutrients and chemical substances affecting an increased number of drinking waters. In addition to this, chemical pollution related to historical mining, industrial and waste sites still persists in some areas.
Twenty-one of the 103 (20%) estuarine and coastal water bodies assessed over the period 2020-2022 were in unsatisfactory condition for dissolved inorganic nitrogen. Nearly all (97%) estuaries and coastal waters assessed over the period 2020-2022 were in satisfactory condition for phosphate.
Loads of nitrogen and phosphate to the marine environment can fluctuate between years depending on the climate however the overall trend is that loads have increased nationally since 2013. Nitrogen loads in 2022 were higher than in 2021 after reducing from the peaks arising from the drought in 2018 and 2019. Phosphate loadings were also higher in 2022 than in 2021. The largest contributions of both nutrients come from catchments that drain from the south east of the country
The latest details on water quality in Ireland, including maps is available on the “Catchments.ie – Water, from source to sea” website (www.catchments.ie).
Ireland’s marine environment is one of the largest in the European Union (EU) and is nearly 10 times its land area. The temperate waters that surround Ireland are highly productive and provide a rich mosaic of marine life, including hundreds of species of invertebrates and fish, 24 species of whales and dolphins, breeding colonies of both the common and grey seal and some of the largest breeding populations of seabirds in Western Europe. The assessment of this wider marine areas is covered under the EU Marine Strategy framework Directive.
Ireland’s location in the Atlantic Ocean on the edge of the European continent has meant that its marine environment has remained relatively unpolluted. In recent years, however, the level of environmental stress, from both internal and external sources, has increased. Coastal development, particularly during the 1990s, has resulted in an increase in the range and magnitude of pressures that have the potential to impact negatively on the quality of Ireland’s tidal waters.