Limerick City drinking water supply exposed to potentially toxic chemical

Stock photo.

IT HAS been revealed that as many as 114,764 people living and working in Limerick City may have been exposed over a number of years to a toxic chemical in drinking water that is believed to be linked to cancer cases.

Uisce Éireann has said it is taking advice on whether it needs to warn more than 220,000 consumers countrywide that their drinking water contains a level of toxic chemicals called trihalomethanes (THMs) in excess of that permitted under European Union limits, according to a report in the Irish Times.

The chemical can be tackled relatively easily by installing a charcoal filter on the water supply at a cost of around €70, but for that to happen, households and businesses need to be alerted if they are affected, environmental campaigners say.

According to HSE advice, “short-term health effects of THMs in drinking water are rare. Therefore temporary raised levels of THMs in drinking water are unlikely to result in any risk to health”.

However, the health body continued, “some studies suggest a link between long term exposure to THMs (i.e. many years) and cancer and reproductive effects but the evidence is not conclusive”.

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“THMs are classified as ‘possibly carcinogenic’ to humans. This means that scientific evidence cannot conclude definitively whether or not THMs cause certain cancers in humans. There is some evidence that THMs cause cancer in animals.

“Some studies suggest that very long-term exposure (e.g. 35 years or more) to high levels of THMs may be linked to a slightly increased risk of some types of cancer in humans, in particular bladder and colon cancer.  The evidence, however, is not conclusive”.

Uisece Éireann has been working for some years to eliminate the chemical from the supply.

A European Court of Justice (ECJ) finding came against Ireland in recent weeks after a case was brought concerning THMs. In its ruling, the ECJ said there is “a potential danger to human health” from THMs.

Supply in Limerick City has been reported as one of those affected, with 114,764 people on the service. Other areas included parts of Kilkenny City, Listowel in County Kerry, and Castletownbere in County Cork,.

The Environmental Protection Agency published a remedial action list for affected areas on foot of that judgement, which has now been update to include supplies not named in the ECJ case which exceed the European Union’s limit for THMs of 100 microgrammes per litre.

Irish law dictates that where the water company and the HSE in consultation “considers that a supply of water intended for human consumption constitutes a potential danger to human health” those affected should be “informed promptly” and “given the necessary advice” to safely consume water.

Asked if it intended to do so, the utility company said: “We are taking the decision under advisement at this time.”

THMs can arise when chlorine is added during the water treatment and purification process.

Uisce Éireann said it had made good some 70 schemes named in the original ECJ case and “it is important to assure customers on the remaining schemes that water is safe to drink”.

Uisce Éireann said it took advice from the HSE concerning THMs and drinking water, and that the advice was that the “benefits of using chlorine to treat our drinking water are much greater than any possible health risk from THMs”.

This is also the World Health Organisation position, which states that adequate disinfection should never be compromised to control THMs.

Friends of the Irish Environment (FIE) first raised the issue and made the official complaint of THMs in drinking water in 2010, saying they are not trying to stop water being disinfected.

“What is required by the EU Drinking Water Directive is to eliminate the THMs,” said FIE director Tony Lowes.

“People could do this themselves with a €70 charcoal filter, but Uisce Éireann needs to warn consumers about that … There can no longer be any doubt since the ECJ decision, that consumers should be notified.”