Fifteen exceedance for the pesticides MCPA and glyphosate were detected in the public drinking water supplies in Louisburgh and Newport in 2019 and 2020.
MCPA is an active substance present in many commonly used herbicide products used to control the growth of thistles, docks and rushes and remains the most commonly detected pesticide in Ireland. These exceedances were detected as part of Irish Water’s public water supply monitoring programme.
The Newport water supply abstracts raw water from the Newport River and the Louisburgh drinking water supply is abstracted from the Bunnahowen River both of which are vulnerable to runoff from land.
Irish Water is asking users of any herbicide or pesticide products in these catchments 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.
Irish Water, 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 at www.pollinators.ie 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, Irish Water’s Regional Drinking Water Compliance Specialist said: "In Mayo, the exceedances of the drinking water regulations for MCPA and glyphosate were noted in the Newport and Louisburgh public water supplies following routine sampling. What’s disappointing is that there were no exceedances in the Louisburgh catchment in 2019, however there were three in 2020.
"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."