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Pesticides detected in Cloneycavan drinking water supply

Uisce Éireann has detected the pesticide Clopyralid in the Cloneycavan water supply zone. The detection was recently found following an exceedance in the Navan Mid Meath public drinking water supply last year. Uisce Éireann is urging domestic gardeners, farmers, grounds keepers and other users of pesticide products to consider the environment and whether pesticide use is necessary in the first instance.

While the pesticide level detected in the Cloneycavan supply does not pose any immediate risk to health, it is imperative that users of pesticides and herbicides are mindful of best practice when spraying their lands. Clopyralid is is a selective herbicide used for control of broadleaf weeds, especially thistles and docks and often ends up in drinking water supplies. Uisce Éireann is asking users of any herbicide or pesticide products in Co Meath to consider the vulnerability of the water supplies to pesticide contamination and the importance of these supplies to the local homes and businesses in the community.

Uisce Éireann, working in partnership with a range of organisations involved in the National Pesticides and Drinking Water Action Group (NPDWAG), is asking the farming community, greens keepers, grounds keepers, and domestic users, to consider in each case whether they need to use pesticides at all. Minimising pesticide use not only helps to protect water quality but also has wider environmental benefits. For example, leaving areas unsprayed can help native flowering plant species to grow and support a range of insects including bees and other vital pollinators. One third of Ireland's bee species are threatened with extinction and by helping the bee population survive and thrive we are also helping to protect our precious water sources. For more information on practical ways to help bees and other pollinators, check out the All-Ireland Pollinator Plan.

Where pesticide use is considered necessary, the NPDWAG is working with the community to ensure that best practice measures to protect drinking water sources and biodiversity are always followed. Farmers and other landholders dealing with the challenge of tackling rushes should note that the Department of Agriculture, Food and the Marine (DAFM) has developed new guidance on the sustainable management of rushes. The new approach is based on the concepts of containment or suppression, and aims to minimise the use of pesticides. More information on this can be obtained from your local farm advisor or on

The efforts to reduce the incidence and level of these detections are being coordinated by the NPDWAG. This group is chaired by the DAFM. 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.

Andrew Boylan, Uisce Éireann's Regional Drinking Water Compliance Specialist said: "These are significantly challenging times for farmers and other essential workers managing land and we are asking everyone to continue to be mindful to protect our raw water sources. Uisce Éireann routinely tests for a wide range of pesticides and 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. In Ireland, the majority (82 per cent) of drinking water supplies come from surface water sources such as rivers, lakes and streams. Supplies such as Cloneycavan are vulnerable to contamination from land and animal run-off. Uisce Éireann asks users of pesticide products in the catchment to consider the vulnerability of the Meath drinking water supply to pesticide contamination and the importance of this supply to the local community."

Adding to this, Dr Aidan Moody, DAFM and Chair of NPDWAG commented: "The continued engagement of all stakeholders, working in partnership, is needed to tackle this issue. Users of pesticides should always consider alternatives in the first instance and if pesticides are essential make sure that they are aware of the best practice measures that should be followed to protect water quality."

Recent drinking water monitoring results for Ireland show that a number of active substances contained in herbicide products used in agriculture, amenity and gardens, such as 2,4-D, fluroxypyr, glyphosate, MCPA, mecoprop and triclopyr, are being regularly detected.

If pesticides have to be used, the basic steps to reduce risks to drinking water sources and the aquatic environment are:

  • Choose the right pesticide product (note that products containing MCPA are NOT approved for use in weed-wipers.)
  • Read and follow the product label
  • Determine the right amount to purchase and use
  • Don't use pesticides if rain is forecast in the next 48 hours
  • Make sure you are aware of the location of all nearby water courses
  • Comply with any buffer zone specified on the product label to protect the aquatic environment. Mark out the specified buffer zone from the edge of the river or lake or other water course and drainage ditches
  • Avoid spills, stay well back from open drains and rinse empty containers 3 times into the sprayer.
  • Store and dispose of pesticides and their containers properly.
  • Never fill a sprayer directly from a water course or carry out mixing, loading or other handling operations beside a water course

Further guidance:

  • A video on the best practice use and application of products containing MCPA can be viewed on our YouTube channel.
  • Information leaflets on pesticide use are also available to download from the Teagasc website.

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