The EPA new annual report on drinking water quality shows that 48 water supplies failed to meet standards for maximum pesticide residues at least once in 2017. This represents four more incidents than in 2016 and confirms the upward trend observed in the past six years.

Of these, four supplies showed "persistent failures" in Listowel, Co Kerry; Kilkenny city; Abbeyfeale, Co Limerick; and Longford central.

The EPA reported that Irish Water was investigating pesticides in 53 supplies serving over 660,000 people at the end of last year, down from 63 supplies affecting 900,000 at the end of 2016.

Almost 80% of all failures detected are of the herbicide MCPA

"Almost 80% of all failures detected are of the herbicide MCPA, commonly used to control rushes in grassland," the EPA found.

The overall increase in the number of drinking water quality failures in 2017 "was mainly due to an increase in the number of pesticide failures," the agency added.

Raising awareness

The National Pesticide and Drinking Water Action Group, led by the Department of Agriculture with representatives from Irish Water, local authorities, the farming community and pesticide manufacturers and suppliers, currently supports raising awareness in areas affected, including communicating responsible pesticide use to farmers through local media.

"However, a national pesticides strategy should be developed to include the actions that are to be taken, when communicating and working with pesticide users does not resolve the problem," the EPA warned.

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MCPA in 80% of drinking water pesticide contaminations

The Environmental Protection Agency (EPA) has called for a national pesticides strategy as multiple water supplies continue to exceed maximum residue standards.