Courtmacsherry Bay and Rincarna Pools in Galway were found to have breached the highest permitted level of nitrogen.
Nitrogen is set as an assessment standard in coastal waters under surface water regulations.
These findings are from the Environmental Protection Agency’s (EPA) latest water quality assessment, which reviewed lakes, rivers, coastal and transitional (estuaries and lagoons) waters and groundwater from the beginning of 2010 to 2015.
Overall, 21% of coastal water was ranked as having a “less than good” status.
However, when it came to the actual surface area, 86% of all monitored coastal water was classified as “high” or “good”.
Other water bodies monitored includes lakes and rivers.
Rivers seemed to have faired poorly in this assessment period, with six being classified as badly polluted.
These were the Tolka between Clonee and Clonsilla in Dublin, the Avoca in Co Wicklow, the Aughboy in Co Wexford, the Bredagh near Moville in Co Donegal, the Laurencetown stream in Co Galway and the Srah river which runs into Lough Mask near Tourmakeady in Co Mayo.
Furthermore, 43% of monitored rivers have a “less than good” ecological status.
However, the most alarming finding relates to the number of rivers which have had a “pristine” status in the past.
The latest assessment period showed that there were only 21 rivers in Ireland classified at the highest rating of “pristine”, whereas in the late 1980s there were 500.
Green Party leader Eamon Ryan described this decline as “one of the great environmental failings of our time”.
“To turn these figures around we need a new national land use plan. We have to move away from the current intensive farming model and adopt ‘High Nature Value’ agriculture instead. This has to benefit the farmer as wel l as the environment,” said Deputy Ryan.
When it came to lakes there were similar findings, with 103 classified as “high” or “good” and 122 ranked as “less than good.”
There were 225 lakes monitored in total.
Between 2010 and 2015, the status of 48 lakes declined compared with the 2007-2009 assessment period and 35 lakes failed the assessment for exceeding the highest permittable level of hazardous substances.
However, 38 lakes registered an improved status compared with the 2007-2009 assessment.
Yesterday, Inland Fisheries Ireland (IFI) expressed its disappointment at the findings.
“From an ecological and angling-tourism perspective, our rivers and lakes are vital national resources”, said Ciaran Byrne, CEO of IFI.
“It is essential that we protect and conserve these assets and water quality has a significant impact on fisheries habitats and populations,” he added.
The IFI cautioned against singling out any particular sector for the standard in water quality across Ireland’s river basins and lakes, backing the EPA’s findings that “multiple factors” are at play.
The IFI CEO also commented on the total number of reported fish kills (97) between 2013 and 2015, which in some instances, the exact cause was unknown and several influences may have played a part.
“There were 31 separate fish kills across the country last year,” said Mr Byrne, “but just eight of those were directly attributable to agricultural activities.”
In addition to the agricultural-related kills, two fish kills were as a result of municipal works and one by industrial works. In four instances, the exact cause of the fish kill was difficult to ascertain while 16 incidents of fish kills were as a result of disease and natural causes.
The EPA assessment concluded that while there has been little overall change in water quality from 2010 to 2015, there has been a failure to meet the planned national target of 13% improvement in water status for the period.