Public drinking water for nearly 240,000 people across the State currently contains toxins above EU safety levels, according to data from the Environmental Protection Agency (EPA).
The European Court of Justice ruled this week that Ireland failed to protect drinking water from toxic chemicals that have been linked in some studies to cancer.
The ruling, announced on Thursday, found Ireland failed to meet obligations to rid public and private water supplies of trihalomethanes (THMs).
EPA data shows drinking water in counties Clare, Cork, Donegal, Kerry, Kilkenny, Limerick, Longford, Meath, Offaly, Roscommon, Tipperary and Wicklow currently contain “elevated levels” of THMs.
These areas include Limerick city, where 114,764 people are exposed to the toxins; Listowel in Co Kerry, where 14,905 people are exposed; and parts of Kilkenny city, where more than 14,000 people are also exposed. Smaller areas such as Castletownbere in West Cork, Glenties-Ardara in Donegal and Aughrim in Wicklow are also affected.
THMs arise when chlorine used for disinfecting tap water mixes with natural organic matter – such as vegetation and leaves – in the water. At elevated levels, THMs have been associated with negative health effects such as cancer and adverse reproductive outcomes.
The Health Service Executive says there is “some evidence that THMs cause cancer in animals” and the chemicals are classified as “possibly carcinogenic” to humans.
However, it stresses: “The benefits of using chlorine to treat our drinking water are much greater than any possible health risk from THMs.”
The court found the concentration of THMs in many Irish public and private supplies exceeded EU safety levels.
It said Ireland had also failed to take measures “as quickly as possible” to restore the quality of drinking water in affected supplies “despite the seriousness of the situation and the potential danger it could do to human health”.
EPA programme manager Noel Byrne said there was no “short term” risk to people’s health when drinking water containing THMs but the situation should not be left “in the longer term”.
“The EU have limits set at the 100 microgrammes per litre and that is in line with the WHO standards,” Mr Byrne told RTÉ's Morning Ireland programme on Friday. “So, there maybe isn’t an acute risk in the short term, but you don’t want that there for the longer term. We need to see these supplies that have THM risks are brought into compliance with the drinking water standards.”
Some 23 of the 54 water supplies across the State, which are currently considering “at risk”, are contaminated by THMs, he said. Uisce Éireann had successfully increased surveillance of drinking water supplies and had identified new areas where THMs are present, he added. “Now they can look at options to correct this,” he said.
Complaints about THMs were made more than a decade ago by the environmental charity Friends of the Irish Environment, and Uisce Éireann was told in 2014 to ensure that the quality of drinking water met EU standards. But in May 2015, the commission told the Irish authorities they were not in compliance with an EU directive on water quality for human consumption.
In May 2020, the court issued a “reasoned opinion” reiterating that THM concentrations exceeded safe levels.
The court gave Ireland until September 2020 to fix the problem.
In response to the Court of Justice decision the Department of Housing issued a statement saying: “It is important to note that the court’s findings refer to the historical position in September 2020.”
It said “considerable progress has been made since then to the water supplies concerned in this case”.
The department said the ruling related to 30 drinking water supplies, nine of them private water group supplies, the remaining 21 provided by Uisce Éireann.
The department said 18 of these 30 water supplies “have already had capital upgrades completed to ensure that treatment levels are compliant with the requirements of the [EU] Drinking Water Directive”.
It said “the remainder are undergoing capital upgrades and improvements and are due to be completed by the end of 2026″.
In a statement on Thursday Uisce Éireann said just five public water supplies from an original list of 21 public supplies remain to be addressed and works are at an advanced stage to resolve these.
But it added its “enhanced testing and monitoring programme has also enabled the utility to identify a number of additional sites where THM risks exist”. In all these cases Uisce Éireann “is taking action to remove the risk of elevated levels of THMs forming in all public water supplies through a combination of plant upgrades and enhanced operational controls”, the utility said.
Tony Lowes, director of the Friends of the Irish Environment, said it has been more than 10 years since the charity first made a complaint to the European Commission in relation to THMs in Irish water. He said it believed the first formal complaint was submitted “in about 2010″, which is now 14 years ago.
“These are very dangerous toxins and they are in drinking water and the water in which people shower,” he said.
“While the situation has got better and better over the years, it’s nowhere near where it should be. And now, with this judgment in hand, if Ireland doesn’t complete the process of providing us with wholesome water we’ll be back to the courts for daily fines,” Mr Lowes told RTÉ's Morning Ireland programme.
“Irish Water needs to take this to the Government and say they must put in the remaining treatment plants that are required so that everybody in the country who is on a public water supply has clean and wholesome water.”
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