Public drinking water found to contain chemicals used to kill slugs and weeds

Irish Independent

28-04-2025

Uisce Éireann said the 66 'exceedances' detected were rare and small and posed no risk to human health.
However, the water utility and other agencies who make up the National Pesticides and Drinking Water Action Group said the aim must be to keep pesticides out of waterways and drinking supplies completely.
They appealed to farmers, landowners and gardeners to review their pesticide usage and to use alternative pest and weed control methods where possible.
'While the overall compliance rate remains very high, all stakeholders must make sustained efforts and be vigilant to protect drinking water quality,' the group said.
The 66 exceedances were detected in 34,000 samples – an increase on the 52 incidents in 2023, although the trend in recent years has been downward.
The affected supplies served populations totalling tens of thousands of people.
'A concerning trend is the number of exceedances outside the spraying ­season for certain plant protection products, particularly in winter,' said Dr Pat O'Sullivan, senior manager with Uisce Éireann.
'We want to remind users to be mindful of water sources when using pesticides, as one drop of pesticide can be detected in a stream up to 30km away.'
The 66 detections were in 22 ­public drinking water supplies, a number of which have had repeated incidents in recent years. The action group has now prioritised several of the affected catchment areas for action.
These include Hacketstown, Co Carlow, Greenmount, Co Louth, and Foynes/Shannon Estuary, Co Limerick.
Extra attention is also being paid to supplies in Clonroche, Co Wexford, and Lough Forbes, Co Longford.
'Similar targeted action in recent years in areas such as Belturbet, Co ­Cavan, and Newport, Co Mayo, has ­successfully eliminated pesticide exceedances in those water supplies,' the group said.
The most commonly found substance last year was MCPA, an ingredient in products used to control rushes, thistle and dock.
Specific advice is available from the Department of Agriculture on how to minimise pesticide use to manage rushes, which are common on wet soils that drain into waterways.
Other exceedances involved 2,4-D, a broad-leaf herbicide; glyphosate, the main ingredient in all-purpose Roundup; clopyralid, also a broad-leaf herbicide; and metaldehyde, used on slugs and snails.
Uisce Éireann has begun a pilot ­project with farmers in Cavan's Erne-Larah catchment area to improve understanding of the impacts of pesticide use on waterways and adopt alternative ways of pest control.
As well as affecting water quality and, potentially, human health, the action group is stressing the harm pesticides cause to flowering plants and the bees and other pollinators who depend on them.
Department of Agriculture official Dr Aidan Moody who chairs the action group said alternative pest-control methods should always be considered first.
'If pesticide application is considered essential, follow best practices to protect water quality,' he said.
'This approach is a win-win for ­water quality and biodiversity.'