Exceedances in pesticides have been detected in drinking water sources in Co Donegal, it has been confirmed.
Now Donegal County Council is appealing to farmers and other users of pesticides to follow the guidelines when applying these substances to their lands.
In Donegal the exceedances were noted in Killybegs, Carrigart-Downings and Donegal (Lough Eske) in 2017 as well as low-level detections in many other supplies.
The council says that while there is no threat to public health, it is imperative that users of pesticides are mindful of best practice when spraying their lands.
In Ireland, the majority (82 per cent) of 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.
In Donegal, no fewer than 11 different public water supplies across the county have seen the herbicide MCPA detected over the past two years, albeit mostly at very low levels. MCPA is used mainly for eradicating rushes, a problem for many years on Irish farms and one that looks like continuing for many more years. It is also found in other weed killer formulations used by gardeners and growers, so its use is quite widespread.
A spokesperson from Donegal County Council explained: “Spring is a time of year for new growth and many people are getting back out into their fields and gardens to assess the effects of winter and prepare for the year ahead.
“In many cases, they are finding that weeds of various kinds have taken over and action needs to be taken to leave space for the plants they want to grow. In the modern era, the use of pesticides has played a central role but the effects of this can be far reaching and more and more detections of pesticides in drinking water are being found across the country.”
MCPA, which is commonly used to kill rushes on wet land, is the main offender, and careless storage, handling and improper application means it ends up in our drinking water leading to breaches of the drinking water regulations.
A single drop of pesticide can breach the drinking water limit in a small stream for up to 30 kilometres. That’s the real and devastating threat that faces Ireland’s drinking water sources.
Drinking water monitoring results for Ireland show that a number of pesticides commonly used on grassland, such as MCPA, are being detected more frequently.
Donegal County Council would like to remind farmers and professional users of pesticides of the need to follow best practice in the application of pesticides such as MCPA on land, particularly near lakes and rivers used as drinking water sources.
The basic steps in reducing pesticide risks are –
· Choose the right pesticide product
· Read and follow the product label
· Determine the right amount to purchase and use
· Don’t spray if rain or strong wind is forecast in the next 48 hours
· Mark out a 5-metre buffer zone from the edge of the river or lake
· 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.
If there is no alternative to applying a pesticide, the weed wiping or licking method, using a tractor or quad, has the advantage of being applied primarily to the target plant – rushes or other tall weeds, and has been shown to use about 1/3 of the amount of pesticide, (compared to boom spraying) and produce much lower losses to waters.
A recently produced video on the correct use of MCPA can be viewed on the Teagasc and DAFM websites. Information leaflets on pesticide use are also available to download from the Teagasc website at www.teagasc.ie
Background
The term pesticides includes a wide range of chemicals used for the control of unwanted pests (most commonly weeds and vermin). While the amount of public water schemes with elevated levels of pesticides above the allowed standard is very small in Ireland, there is increasing evidence of pesticides in water sources as a result of run-off from weed control on hard surfaces, gardening, agriculture or forestry.
The presence of an individual pesticide at levels exceeding the allowed value tells us that there may have been careless or excessive use of a product in the source catchment or in the vicinity of treated water retaining infrastructure.
The highest incidences of pesticide exceedances encountered in Ireland’s drinking water is MCPA, a commonly used herbicide present in many products used to control thistle, dock and rush.
What risk does this pose and what is the response?
Pesticides do not pose any immediate risk to health.
Ensuring that pesticides do not enter drinking water supplies requires a strong protection plan for the water source and that the general public is informed of the correct and safe use of pesticides. A national group has been formed to take action to address pesticides and devise and deliver various educational campaigns. This group has members from numerous state bodies and organisations including the EPA, Department of Agriculture, Teagasc, Coillte, Local Authorities and Irish Water.
In the case of individual pesticide exceedances Irish Water engages with the relevant statutory authorities with responsibility for protecting the catchment in that area (e.g. Local Authority Environment Sections, EPA catchment units) to investigate the possible cause of the contamination and take any necessary remedial actions.
Teagasc provides useful advice on various treatment options available to farmers and this can be downloaded on www.teagasc.ie
