BREACHES OF international limits for trihalomethanes (THMs) in Irish public water supplies are being analysed by the Environmental Protection Agency (EPA) as part of its supervisory role under the EU directive on drinking water.
In a statement yesterday responding to a warning by Friends of the Irish Environment that several water supplies were in breach of the limits for the carcinogenic chemicals, the agency said this research project would be completed by the end of 2011.
The project will assess a “sample number” of water supplies with THM exceedances, provide “expert comment” on solutions for resolving THM issues and prepare recommendations to deal with breaches of the limits as well as technical guidance for local authorities.
But while the EPA said “every effort possible” should be made to reduce concentrations of disinfection byproducts, including THMs – byproducts of chlorination that arise when water contains organic matter – it emphasised the health risks from such sources “are much less than the risk from consuming water that has not been disinfected”.
Each year, the EPA collects and analyses more than 250,000 local authority monitoring results for drinking water supplies and publishes a report assessing their safety and security. It also maintains a “remedial action list” (RAL) for supplies not in compliance.
“The population served by water supplies that are now safe and secure and have been removed from the RAL is over 500,000. However, the remaining supplies on the RAL collectively supply water to a population of 1,162,112 persons,” the agency said.
“These figures will be updated later this year as part of EPA’s annual drinking water reporting to the public.” But the agency said it was “the responsibility of local authorities to advise consumers in the event of a public health issue”, such as when E.coli is detected.
It recommended that anyone concerned about tapwater should contact the local authorities, which had the latest results and would make them available on request. Alternatively, results monitoring may be available directly from local authority websites.
