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Pesticides detected in South Leitrim drinking water supply

An exceedance for the pesticide MCPA has been detected in the South Leitrim Regional Water Supply Scheme. MCPA is an active substance present in many commonly used herbicide products used to control the growth of thistles, docks and rushes. The exceedance was detected as part of Uisce Éireann’s public water supply monitoring programme.

The South Leitrim Regional Water Supply Scheme abstracts raw water from the Shannon River which is vulnerable to runoff from land. Uisce Éireann is asking users of any herbicide or pesticide products in the Shannon River catchment to consider the vulnerability of the water supplies to pesticide contamination and the importance of this supply 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 www.pcs.agriculture.gov.ie/sud/waterprotection.

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.

Dr Pat O'Sullivan, Compliance Specialist for Uisce Éireann said: “In Co. Leitrim, the exceedance of the drinking water regulations for MCPA was noted in the South Leitrim regional public water supply following routine sampling in June. While our consultation with the HSE has concluded that the levels seen do not represent a threat to public health, it is however undesirable and therefore imperative that users of pesticides are mindful of best practice when using herbicides or pesticides and seek out alternatives.”

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 Uisce Éireann’s YouTube channel.
  • Information leaflets on pesticide use are also available to download from the Teagasc website.