Irish Water has appealed to farmers, ahead of the spraying season, after finding pesticides breaching EU levels in several public water supplies.
While there is no threat to public health from the exceedances, the utility said it’s important that farmers follow best practice in the handling, storage, and spraying of pesticides, so as to protect public drinking water sources and prevent breaches of the drinking water regulations.
Irish Water said exceedances in pesticides in public water supplies (PWS) are on the increase across Donegal, Cavan, Galway, Mayo, and Monaghan.
MCPA, which is used to kill rushes on wetland, is one of the most commonly found. It usually ends up in drinking water as a result of careless storage, handling, or improper application.
Cypermethrin, glyphosate, and fluroxypyr have also been found at levels above EU limits.
In Cork, Irish Water has found traces of MCPA above EU levels in the Glanmire, Glengarriff, and Macroom PWS, and an exceedance of the weedkiller 2,4-D in the Glanmire public water supply.
The regulations are so stringent that a single drop of pesticide is enough to breach the drinking water limit in a small stream for up to 30km.
Irish Water’s regional drinking water compliance specialist, Deirdre O’Loughlin, said 82% of the country’s drinking water supplies come from surface water sources (water from rivers, lakes, and streams).
Such supplies are vulnerable to contamination from land and animal run-off.
She said Irish Water said it is working with the National Pesticide and Drinking Water Action Group, chaired by the Department of Agriculture, to encourage farmers, and other users of pesticides, to follow best practice during spraying season.
Dr Aidan Moody, chair of the NPDWAG, said such a partnership approach is needed to reduce the risk posed by pesticides.
“Users of pesticides should make sure that they are aware of the best practice measures that should be followed to protect water quality,” he said.
Irish Water has produced an online video to help farmers reduce pesticide risks, including knowing how much pesticide to buy and use, how to store it safely, how to observe buffer zones, and advising them not to spray if rain or strong wind are forecast within 48 hours.
Advice is also available on the Teagasc website.