28-04-2025
Increase in presence of pesticides in water supplies
Pesticide users have been urged to be vigilant to protect drinking water supplies ahead of the warmer weather expected over the coming weeks and months.
It comes after there has been an increase in the number of drinking water supply samples that have exceeded the legal limits for pesticides.
Uisce Éireann's public water supply monitoring programme found that of the 34,000 samples tested last year, pesticide levels exceeded legal limits 66 times.
This figure is up from 52 exceedances in 2023. However, overall, the trend is down by more than 50% since 2017.
The River Dee in Co Louth runs through one of the areas where Uisce Éireann has detected recurring pesticide levels that are above the legal limit.
Uisce Éireann also announced that two other catchment areas have been identified where recurring pesticide exceedances have been detected.
These are Hacketstown, Co Carlow and Foynes Shannon Estuary in Co Limerick.
The utility has said while the pesticide levels detected in areas such as these do not pose a risk to public health, it is advising all stakeholders to stay vigilant to protect drinking water supplies.
As a result, catchment-based focus groups have been established in these areas to co-ordinate targeted actions at a local level and prioritise these areas for "further work" in 2025.
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.
A pesticide is a substance that prevents insects, weeds and other pests from harming plants. T
hey are used in many industries, including agriculture, forestry, transport, domestic gardens and amenities such as public parks and golf courses.
Most public drinking water supplies in Ireland come from surface water, for example rivers, lakes and streams.
The HSE National Drinking Water Group has said that pesticides can get in to surface water in a few different ways:
By direct spraying of rushes and other weeds with pesticides close to a river or stream
From pesticide run-off from land into a stream during heavy rain; and
Sprayed pesticide can drift in the wind onto a stream, river or lake
Pesticides can also get into drinking water through misuse or careless handling of containers during storage or disposal.
Therefore, the National Pesticides and Drinking Water Action Group is reminding users of herbicides and other pesticide products to always take account of the vulnerability of their local drinking water supplies.
The body, which works to achieve compliance with the EU Drinking Water Directive, is also asking pesticide users to be aware of how their actions could impact their community's drinking water.
Asset Strategy, Technical Lead with Uisce Éireann, Gareth O'Brien has said water supply samples taken from the Greenmount catchment area in Co Louth continue to exceed the legal limits for pesticides.
"The water flows through Ardee along the River Dee and is extracted about ten kilometres upstream at the Greenmount water supply.
"The water undergoes the water treatment process here and that is where we test the final treated water and that is where we are getting the pesticide exceedances.
"We're asking all pesticide users in the catchment area just to be mindful of the water supply and whenever using pesticides just follow best practices and advice," Mr O'Brien added.
Alan McEvoy is a 33-year-old agronomist and crop advisor living in the Ardee area.
His role involves carrying out farm inspections before providing advice to farmers on what pesticides should be applied and in what quantities to ensure such substances are used safely and also yield the greatest crop return.
Mr McEvoy has said that while farmers, greenkeepers and amenity owners must evaluate their use of pesticides, those at home also have a role to play.
"In the public eye, the main thing people see is a sprayer driving through a town or village and most people think, 'there's the fella or the woman that's basically polluting the water that I'm drinking'.
"Nine times out of ten, or even more, it's actually the home use of pesticides on hard surfaces that is really doing more damage than the farm.
"The farmer is usually trained to apply the pesticides, they are after getting professional advice, they're sticking to within their guidelines, including the limits within the buffer zones.
"If you're spraying at home, your garden with a lawn-care or the weeds around your house, there's usually more damage done with that because you're spraying onto a hardcore surface and there's nothing there to bind the pesticide and prevent run-off."
In the first instance, Uisce Éireann is advising farmers and landowners not to use pesticides if at all possible, or else consider using an alternative.
If pesticides must be used, the utility has said there are basic steps that can be taken to reduce the risks to drinking water sources and the aquatic environment.
These include using a pesticide correctly as directed by the product's label, not using pesticides if rain is forecast within the next 48 hours, and by being aware of the location of all nearby watercourses, including drains, wells and springs.
