THE AMOUNT OF pesticides detected in Irish drinking water supplies increased in the past year.

A total of 81 pesticide exceedances were detected by Ireland’s public water supply monitoring programme during 2020. This represents an increase of five incidences on the previous year.

MCPA remains the most commonly detected pesticide in drinking water sources. The powerful herbicide is an active substance present in many commonly used products for controlling the growth of thistles, docks and rushes. 

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Irish Water said there are six priority catchment areas of particular concern where  frequent pesticide exceedances have been detected.

These are:

• Longford Central, Co Longford (MCPA),
• Newcastlewest, Co Limerick (MCPA),
• Belturbet, Co Cavan (MCPA),
• Clonroche, Co Wexford (Bentazone),
• Newport, Co Mayo (Glyphosate/MCPA),
• Foynes Shannon Estuary, Co Limerick.

Irish Water urged the farming community, greens keepers, grounds keepers, and domestic users, to consider whether they need to use pesticides at all.

“Leaving areas unsprayed can help native flowering plant species to grow and support a range of insects including bees and other vital pollinators,” the utility company said.

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.

An exceedance for the pesticide 2,4-D was detected in Dublin city’s public drinking water supply in August last year.

Irish Water said today that, following consultation with the Health Service Executive (HSE), it 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,” Andrew Boylan, Irish Water’s Regional Drinking Water Compliance Specialist, said.

The water supply relies on raw water from the River Liffey, which is vulnerable to pesticide runoff from land.

The 2,4-D pesticide was one of the active ingredients in Agent Orange and has been shown to drift considerable distances from where it’s applied. Agent orange is infamous for its use by the US military during the Vietnam War to destroy crops and forest covers. 

Research has linked 2,4-D to endocrine disruption, disturbing estrogen, androgen and thyroid hormones. The International Agency for Research on Cancer also named the weed killer a possible human carcinogen.

Irish Water is asking users of any herbicide or pesticide products in the Liffey catchment to consider the vulnerability of the water supplies to contamination and the importance of this supply to the local homes and businesses in the community.