The EU Environment Commissioner, Ms Margot Wallström, yesterday welcomed a report showing that river-water quality in Ireland has improved for the first time since national surveys began in 1971.
However, she said the report, compiled by the Environmental Protection Agency (EPA), also showed that a lot more needed to be done, particularly in dealing with the persistence of agricultural pollution.
The report, Water Quality in Ireland 1998-2000, classifies 70 per cent of river channel length as unpolluted, an improvement of 3 per cent since 1995-1997. This means that almost 400km of previously-polluted river channel is now in satisfactory condition.
Significantly, most of the improvements in river-water quality have occurred in catchments where new anti-pollution measures have been put in place, notably nutrient-management programmes and phosphorus removal from sewage treatment plants.
Wider catchment management programmes which anticipate the requirements of the EU Water Framework Directive are being implemented for Lough Derg and Lough Ree on the Shannon, as well as the Boyne, Liffey and Suir catchments.
The report warns, however, that increased efforts are required to bring water pollution under control given that 30 per cent of Irish river channel is still polluted. Phosphorus enrichment is the main cause of this pollution.
The more densely populated and intensively farmed regions are the most polluted: the eastern region and Cavan-Monaghan are worst affected by all levels of pollution, while Donegal-Sligo, the southern region and the western region are the least polluted.
Some of the larger rivers seriously polluted include the Boyne; the Finn, Co Donegal; the Liffey below the Osberstown sewage treatment works in Co Kildare; the Triogue below Portlaoise; the Tullamore River; and the Deel in west Limerick.
A small number of rivers which were seriously polluted in the 1970s, notably the Avoca in Co Wicklow, are still in that state. Many cases of long-term agricultural pollution continue without any abatement, the EPA complains.
Similarly, even though there was an overall reduction in the level of serious pollution, the length of seriously-polluted river channel attributed to sewage discharges has actually increased, mainly due to the overloading of some treatment works.
In the case of the lakes, 85 per cent were in satisfactory condition. However, some long-term chronic pollution existed, as in Lough Sheelin, Co Cavan, which is affected primarily by agricultural pollution from intensive pig factories.
More positively, the report notes a striking reduction in algal growth in Lough Ree and Lough Derg following the establishment in the Shannon of the filter-feeding Zebra mussel and a phosphorus-removal programme at 17 sewage treatment plants.
Estuaries are generally in good condition, but some serious problems still exist due to organic pollution from local waste discharges. Some 13 tidal areas are now classified as eutrophic (over-enriched), and four others are potentially in this condition.
Groundwaters have an unacceptably high level of contamination, with 38 per cent of samples showed faecal coliform contamination. The EPA is advising anyone with a private well to disinfect or sterilise water before using it for consumption.
High nitrate levels were also reported in 20 per cent of the sampled wells due to poor control of animal wastes and poor siting of septic tanks, while high ammonia levels were found in Cavan, Donegal, Kerry, Leitrim, Limerick, Meath, Monaghan and Waterford.
"Irish bathing waters continued to show a generally very high standard during the period and they compare very favourably with the rest of Europe in terms of quality," the report says.
"The situation regarding toxic substances in Irish waters is also good."