The pesticide MCPA has been detected at levels above the permitted amount in the public drinking water supplies in Glaslough and Emyvale, Co Monaghan for the second time in two months. MCPA is a commonly used herbicide present in many products used to control thistles, docks and rushes. The exceedances were noted following routine sampling of drinking water supplies. Three further exceedances were recorded in these schemes in 2019. 

These two supplies source their water from the Glaslough Tyholland Group Water Scheme which takes its water from Emy Lough. This lake is vulnerable to contamination from land and animal run-off and Irish Water is asking users of pesticide products in the Emy Lough catchment to consider the vulnerability of the water supplies to pesticide contamination and the importance of this supply to the local community.

Irish Water, working in partnership with a range of organisations involved in the National Pesticides and Drinking Water Action Group (NPDWAG), is providing advice and guidance to all users of pesticides including the farming community, greens keepers and grounds keepers and domestic users, to ensure that best practice measures to protect drinking waters 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 www.pcs.agriculture.gov.ie/sud/waterprotection

The efforts to reduce the incidence of these detections are being coordinated by the NPDWAG. This group is chaired by the Department of Agriculture, Food and the Marine (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. 

Dr Pat O’Sullivan, Irish Water’s Regional Drinking Water Compliance Specialist said: “In Co Monaghan, the exceedance of the drinking water regulations for MCPA was noted in the Glaslough and Emyvale public water supplies following routine sampling this month and last. While the HSE has advised that the levels seen do not represent a threat to public health, it is however undesirable and it is therefore imperative that users of pesticides are mindful of best practice when spraying their lands or looking after their gardens.

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 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 pesticides commonly used such as Bentazone, Glyphosate, MCPP, MCPA, Clopyralid and Fluroxypyr, are being detected more frequently.

Irish Water working in partnership with the National Pesticides and Drinking Water Action Group would like to remind farmers and professional users of pesticides to follow best practice in the application of pesticides on land, particularly near lakes and rivers used as drinking water sources.

If pesticides have to be used, the basic steps in reducing risks 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 spray if rain or strong wind 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
  • Never fill a sprayer directly from a water course or carry out mixing, loading or other handling operations beside a water course
  • 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.


A recently produced video on the correct use of MCPA can be viewed our Irish Water YouTube channel.

Information leaflets on pesticide use are also available to download from the Teagasc website.

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