Irish Water is warning that pesticides have been detected in drinking water supplies across Ireland – the water company is urging farmers and other users to use best practice when spraying pesticides.

Products for grassland weed control containing substances such as MCPA, fluroxypyr and 2,4-D, among others have been detected in drinking water supplies across Ireland - the detected levels sometimes exceed the legally permitted limit value for pesticides in drinking water.

MPCA is main offender

The majority (82 per cent) of drinking water supplies in Ireland come from surface water sources such as rivers, lakes and streams. 

MCPA, which is commonly used to kill rushes on wet land, is the main offender. However, Irish Water said other pesticides such as 2,4-D, fluroxypyr and MCPP (also known as mecoprop) are being detected more frequently than in previous years.

Careless storage, handling or improper application of any pesticide product can easily result in traces ending up in drinking water, leading to breaches of the drinking water regulations. Users of pesticides are being asked to carefully consider how these products may access water courses via rainwater drains, drainage channels or other means before application.

The water company is highlighting a number of areas where the pesticides have been detected, including:

Kilkenny

The Kilkenny City/Troyswood Water supply is on the action list and while the pesticide levels detected in the Kilkenny City/Troyswood Water supply do not pose any immediate risk to health, the water company said it is imperative that users of pesticides are mindful of best practice when spraying their lands.

There have been eight detections of pesticides in the Nore catchment in the past three weeks. The majority of these detections relate to the pesticide MCPA, but there have also been detections of the pesticide 2,4-D and 2,4-DB. Supplies such as the Kilkenny City/Troyswood Water Supply are vulnerable to contamination from land and animal run-off. Irish Water is asking users of pesticide products in the River Nore catchment to consider the vulnerability of the Kilkenny City/Troyswood water supply to pesticide contamination.

Galway

The pesticide MCPA has been detected in the Tully-Tullycross Public Water Supply in Co Galway following a year of clear sampling results. The Tully-Tullycross supply was on the Environmental Protection Agency’s (EPA’s) watch list for pesticides due to persistent exceedances for MCPA. However, following a year of clear sampling results, the file was removed, but the EPA has notified Irish Water that it will be put back on its watch list following the latest exceedance.

Limerick

There have been 20 detections of pesticides in the Deel catchment in the past three weeks, while the Feale catchment has seen six detections in the same period. The majority of the detections relate to the pesticide MCPA, but there have also been detections of the pesticide 2,4-D and 2,4-DB. The Deel and Feale river catchments are among eight priority catchment areas of particular concern around the country where exceedances of pesticides are persistent. All of these areas are being prioritised for action by members of the National Pesticides and Drinking Water Action Group (NPDWAG).

Meath

The Navan/Mid Meath drinking water supply in Co Meath which is covered by the River Blackwater and Boyne catchments is on the watch list. Fluoroxypyr and trichlopyr exceedances were recorded in the supply in June, the first exceedances in 2019 to date.

Louth

Ardee, Cavanhill and Tallanstown supplies in Louth are on the EPA watch list

Single drop of pesticide enough to breach drinking water limit in a small stream for up to 30 kilometres

Irish Water, working in partnership with a range of organisations involved in the National Pesticides and Drinking Water Action Group (NPDWAG) is appealing to all users of pesticides including the farming community, sporting organisations and domestic users, to ensure that best practice measures to protect drinking waters are always followed.

The water company is pointing out that the regulations are so stringent that a single drop of pesticide is enough to breach the drinking water limit in a small stream for up to 30 kilometres. This clearly highlights the level of care needed to protect drinking water sources, Irish Water said.

There are currently eight priority catchment areas of particular concern where exceedances of pesticides are persistent. The areas cover the Lough Forbes catchment in Co Longford, the River Deel and River Feale catchments in Limerick, the Clonroche Water Supply in Wexford, the River Nore in Kilkenny, Lough Acanon in Cavan, the River Erne in Cavan and Newport in Co Mayo. All of these areas are being prioritised for action by members of the NPDWAG.

Watch list currently comprising over 20 supplies

There is also a separate watch list, currently comprising over 20 supplies, which is also a focus for targeted actions, since the pattern of detections in these areas indicates a risk of persistent pesticide exceedances.

Efforts to reduce the incidence of detections are being coordinated by the NPDWAG which is chaired by the Department of Agriculture, Food and the Marine.

All of the key stakeholders are represented in this group and include other Government departments and agencies; local authorities; industry representative bodies; farming organisations; water sector organisations; and amenity sector organisations.

“Providing safe, clean drinking water for all is our first priority”

Commenting, Dr Pat O’Sullivan, Irish Water’s Regional Drinking Water Compliance Specialist, said:

“While MCPA accounted for the majority (75 per cent) of pesticide exceedances detected nationally in public water supplies during 2018, Irish Water routinely tests for a wide range of pesticides and is closely monitoring the situation for pesticides other than MCPA.”

“Irish Water is continuing its extensive investment programme to safeguard the water supply for homes, farms and businesses in Ireland. Providing safe, clean drinking water for all is our first priority.”

Dr Aidan Moody, Chair of the NPDWAG commented:

“A lot of good work has been done and progress has been made. The continued engagement of all stakeholders, working in partnership, is needed to make further progress. Users of pesticides should always consider in the first instance if there are alternative non-chemical weed/pest control methods that would be feasible. If pesticides have to be applied users must make sure that they are aware of and follow best practice measures to protect water quality.”