THE ISSUE OF trihalomethane (THM) contamination has been raised by a group campaigning to have 380,000 consumers directly notified about the quality of the water they are drinking.

In a statement released today, Friends of the Irish Environment said Irish Water should directly inform the hundreds of thousands of customers affected by the contamination, which has been an issue for a number of years.

What are THMs?

Trihalomethanes are toxic compounds which occur as a result of a reaction between organic materials, like peaty soil, when chlorine is added as a disinfectant.

Long-term exposure to THMs has been linked to an increased risk of certain cancers as well as heart, lung, liver and kidney problems.

The last paper submitted to the EU identified supplies to approximately 380,000 households have exceeded the parametric limit for these toxins.

How can I find out if I’m affected?

The latest study by the Environmental Protection Agency (EPA) found that the majority of supplies impacted by this contamination were in Donegal, Kerry and Wicklow. The highest level of THMs was in a supply in Roscommon.

In response to a query from TheJournal.ie, Irish Water said full details of all drinking water parameters for all public supples are available on its website.

To check your supply, enter your address and scroll to the table at the bottom of the page. Here, you can see the results of the sample tests in the last two years, including those for THMs:

The EPA has also compiled a list of water supplies considered ‘at risk’ in terms of drinking quality. Irish Water points out that this does not mean the water is not safe to drink, but there may be deficiencies that need to be resolved.

The EPA updates its Remedial Action List every three months. The most recent list can be found here.

Friends of the Irish Environment recently appealed to the European Ombudsman Emily O’Reilly to compel Irish Water to directly inform consumers of contamination on their bills. However, she said that the European Commission could not force the company to do this.

The lobby group accepted that Irish Water points customers to the EPA’s list, mentioned above, but pointed out that this list omits supplies covering almost 150,000 of the affected consumers.

What is being done?

Firstly, the environmental lobby group is currently taking legal advice about consumer rights in its bid to push Irish Water to directly relay this information to its customers.

For its part, Irish Water pointed out that the World Health Organisation has said that adequate disinfection should never be compromised in attempting to meet guidelines for THMs.

Where the THM limit is exceeded, Irish Water must ensure that disinfection is not compromised. Inadequate disinfection of drinking water can lead to a range of illnesses, some of which could prove life threatening to customers, especially vulnerable customers.

It said the majority of water quality compliance issues in the country relate to a requirement for coagulation and filtration based processes for water treatment.

“The current and future capital investment plans by Irish Water will address long standing THM non-compliances by introducing the appropriate treatment technology.”